Notes
1
Glossary
- abdominopelvic cavity
Division of the anterior (ventral) cavity that houses the abdominal and pelvic viscera.
- abducens
Sixth cranial nerve; responsible for contraction of one of the extraocular muscles.
- abduction
Movement in the coronal plane that moves a limb laterally away from the body; spreading of the fingers.
- accommodation
(In vision) Changes in lens shape to affect refraction of incoming light rays.
- acetabulum
Large, cup-shaped cavity located on the lateral side of the hip bone; formed by the junction of the ilium, pubis, and ischium portions of the hip bone.
- acetylcholine
An important neurotransmitter.
- actin
Protein that makes up most of the thin myofilaments in a sarcomere muscle fibre.
- action potential
Change in voltage of a cell membrane in response to a stimulus that results in transmission of an electrical signal; unique to neurons and muscle fibres.
- active transport
Form of transport across the cell membrane that requires input of cellular energy.
- adduction
Movement in the coronal plane that moves a limb medially toward or across the midline of the body; bringing fingers together.
- adenosine diphosphate (ADP)
Lower energy form of ATP, containing two phosphate groups after the third phosphate group phosphorylated another molecule and transferring energy to it.
- adenosine triphosphate (ATP)
Nucleotide containing ribose and an adenine base that is essential in energy transfer.
- adipocyte
Lipid storage cells.
- adipose tissue
Specialized areolar tissue rich in stored fat.
- adrenal gland
Endocrine glands located at the top of each kidney that are important for the regulation of the stress response, blood pressure and blood volume, water homeostasis, and electrolyte levels.
- adrenal medulla
Inner layer of the adrenal glands that plays an important role in the stress response by producing epinephrine and norepinephrine.
- adrenergic
Synapse where norepinephrine is released, which binds to α- or β-adrenergic receptors.
- agonist
(Also, prime mover) muscle whose contraction is responsible for producing a particular motion.
- alkaline
An ionic solution with basic properties (pH >7).
- amacrine cell
Type of cell in the retina that connects to the bipolar cells near the outer synaptic layer and provides the basis for early image processing within the retina.
- amino
Chemical functional group NH2, a component of amino acids.
- amino acid
Building block of proteins; characterized by an amino and carboxyl functional groups and a variable side-chain.
- amphiarthrosis
Slightly mobile joint.
- amphipathic
Molecule that contains both hydrophilic and hydrophobic regions;.
- ampulla
In the ear, the structure at the base of a semicircular canal that contains the hair cells and cupula for transduction of rotational movement of the head.
- anabolic reaction
Reactions that build smaller molecules into larger molecules.
- anaerobic
Production of ATP in the absence of oxygen.
- anion
Atom with a negative charge.
- antagonist
Muscle that opposes the action of an agonist.
- antagonistic
Muscle that opposes the action of an agonist.
- antebrachial
Relating to the forearm.
- antebrachium
Lower arm, between elbow and wrist.
- anterior
Describes the front or direction toward the front of the body; also referred to as ventral.
- anterior cavity
See ventral cavity
- anterior horn
Gray matter of the spinal cord containing multipolar motor neurons, sometimes referred to as the ventral horn.
- antibody
(Also, immunoglobulin) antigen-specific protein secreted by plasma cells.
- aorta
Largest artery in the body, originating from the left ventricle and descending to the abdominal region where it bifurcates into the common iliac arteries at the level of the fourth lumbar vertebra; arteries originating from the aorta distribute blood to virtually all tissues of the body.
- apical
That part of a cell or tissue which, in general, faces an open space.
- apocrine sweat gland
Type of sweat gland that is associated with hair follicles in the armpits and genital regions.
- apoptosis
Programmed cell death.
- appendicular skeleton
All bones of the upper and lower limbs, plus the girdle bones that attach each limb to the axial skeleton.
- aqueous humour
Watery fluid that fills the anterior chamber containing the cornea, iris, ciliary body, and lens of the eye.
- arachnoid granulation
Outpocket of the arachnoid membrane into the dural sinuses that allows for reabsorption of CSF into the blood.
- arachnoid mater
Middle layer of the meninges named for the spider-web–like trabeculae that extend between it and the pia mater.
- arachnoid trabeculae
Filaments between the arachnoid and pia mater within the subarachnoid space.
- areolar connective tissue
A type of connective tissue proper that shows little specialization with cells dispersed in the matrix.
- arrector pili
Smooth muscle that is activated in response to external stimuli that pull on hair follicles and make the hair “stand up”.
- articular capsule
Connective tissue structure that encloses the joint cavity of a synovial joint.
- articular cartilage
Thin layer of cartilage covering an epiphysis; reduces friction and acts as a shock absorber.
- articular disc
Meniscus; a fibrocartilage structure found between the bones of some synovial joints; provides padding or smooths movements between the bones; strongly unites the bones together.
- ascending tract
Central nervous system fibers carrying sensory information from the spinal cord or periphery to the brain.
- atlas
First cervical (C1) vertebra.
- atom
The smallest unit of an element that retains the unique properties of that element.
- atomic number
Number of protons in the nucleus of an atom.
- auricle
Fleshy external structure of the ear.
- autonomic nervous system
Functional division of the nervous system that is responsible for homeostatic reflexes that coordinate control of cardiac and smooth muscle, as well as glandular tissue.
- avascular
Lacking blood vessels.
- axial skeleton
Central, vertical axis of the body, including the skull, vertebral column, and thoracic cage.
- axis
Second cervical (C2) vertebra.
- axon
Single process of the neuron that carries an electrical signal (action potential) away from the cell body toward a target cell.
- axon hillock
Tapering of the neuron cell body that gives rise to the axon.
- axon segment
Single stretch of the axon insulated by myelin and bounded by nodes of Ranvier at either end (except for the first, which is after the initial segment, and the last, which is followed by the axon terminal).
- axon terminal
End of the axon, where there are usually several branches extending toward the target cell.
- azygous vein
Originates in the lumbar region and passes through the diaphragm into the thoracic cavity on the right side of the vertebral column; drains blood from the intercostal veins, esophageal veins, bronchial veins, and other veins draining the mediastinal region; leads to the superior vena cava.
- ball-and-socket joint
Synovial joint at which the rounded portion of a bone rotates within a ring formed by a ligament and an articulating bone; functionally classified as uniaxial joint.
- basal
That part of a tissue close to underlying body structures.
- basal cell
Type of stem cell found in the stratum basale and in the hair matrix that continually undergoes cell division, producing the keratinocytes of the epidermis.
- basal lamina
Thin extracellular layer that lies underneath epithelial cells and separates them from other tissues.
- basal nuclei
Nuclei of the cerebrum (with a few components in the upper brain stem and diencephalon) that are responsible for assessing cortical movement commands and comparing them with the general state of the individual through broad modulatory activity of dopamine neurons; largely related to motor functions, as evidenced through the symptoms of Parkinson’s and Huntington’s diseases.
- basement membrane
In epithelial tissue, a thin layer of fibrous material that anchors the epithelial tissue to the underlying connective tissue; made up of the basal lamina and reticular lamina.
- basilar membrane
In the ear, the floor of the cochlear duct on which the organ of Corti sits.
- biaxial joint
Type of diarthrosis; a joint that allows for movements within two planes (two axes).
- biceps brachii
Two-headed muscle that crosses the shoulder and elbow joints to flex the forearm while assisting in supinating it and flexing the arm at the shoulder.
- biceps femoris
One of the hamstring muscles.
- bile
Alkaline solution produced by the liver and important for the emulsification of lipids.
- bipolar cell
Cell type in the retina that connects the photoreceptors to the ganglion cells.
- body (of a vertebra)
anterior portion of each vertebra that supports the body weight.
- body (of a vertebrae)
(Also, centrum) the anterior portion of each vertebra that supports the body weight.
- brachioradialis
Muscle that can flex the forearm quickly or help lift a load slowly.
- brachium
Upper arm, between shoulder and elbow.
- brevis
Short
- Brodmann’s areas
Mapping of regions of the cerebral cortex based on microscopic anatomy that relates specific areas to functional differences, as described by Brodmann in the early 1900s.
- buffer
A chemical system that resists change in pH of a solution by either accepting or releasing hydrogen ions in response to acids or bases, respectively.
- bulbous corpuscle
(Also, Ruffini corpuscle) Cutaneous receptors sensitive to skin stretch and sustained pressure.
- bursa
Connective tissue sac containing lubricating fluid that prevents friction between adjacent structures, such as skin and bone, tendons and bone, or between muscles.
- caecum
Beginning of the large intestine, forming a small pouch.
- calcaneus
Heel bone; posterior, inferior tarsal bone that forms the heel of the foot.
- calmodulin
Regulatory protein that facilitates contraction in smooth muscles.
- canaliculi
(Singular = canaliculus) channels within the bone matrix that house one of an osteocyte’s many cytoplasmic extensions that it uses to communicate and receive nutrients.
- cancellous bone
See spongy bone
- capillary
Smallest of the blood vessels where physical exchange occurs between the blood and tissue cells surrounded by interstitial fluid.
- carbohydrate
Class of organic compounds built from sugars, molecules containing carbon, hydrogen, and oxygen in a 1-2-1 ratio.
- carboxyl (COOH)
Chemical functional group consisting of COOH, an important part of organic acids.
- cardiac muscle
Heart muscle, under involuntary control, composed of striated cells that attach to form fibres, each cell contains a single nucleus, contracts autonomously.
- carotid sinus
One of a pair of small pockets near the base of the internal carotid arteries that are the locations of the baroreceptors and chemoreceptors that trigger a reflex that aids in the regulation of vascular homeostasis
- carpal
One of the eight small bones that form the wrist and base of the hand; these are grouped as a proximal row consisting of (from lateral to medial) the scaphoid, lunate, triquetrum, and pisiform bones, and a distal row containing (from lateral to medial) the trapezium, trapezoid, capitate, and hamate bones.
- carrier protein
Membrane-spanning protein that binds to substances it needs to transport, changes shape and moves the substance into or out of the cell (a form of facilitated diffusion, or active transport pumps when energy is required).
- cartilage
Semi-rigid connective tissue found on the skeleton in areas where flexibility and smooth surfaces support movement.
- cartilaginous joint
Joint at which the bones are united by hyaline cartilage (synchondrosis) or fibrocartilage (symphysis).
- catabolism
Chemical reaction that breaks down more complex organic molecules.
- cation
Ion with a positive charge.
- caudal
See inferior
- caveolae
Invaginations of the smooth muscle sarcolemma.
- cell cycle
Life cycle of a single cell, from its birth until its division into two new daughter cells.
- cell differentiation
Process by which unspecialized cells become more specialized in structure and function.
- cellular respiration
Production of ATP from glucose oxidation via glycolysis, the Krebs cycle, and oxidative phosphorylation.
- central
(In anatomy) describes a position towards the middle (centre) of a structure or organ system.
- central canal
(Also Haversian canal) longitudinal channel in the center of each osteon; contains blood vessels, nerves, and lymphatic vessels.
- central neuron
Specifically referring to the cell body of a neuron in the autonomic system that is located in the central nervous system, specifically the lateral horn of the spinal cord or a brain stem nucleus.
- cerebellum
Region of the adult brain connected primarily to the pons that developed from the metencephalon (along with the pons) and is largely responsible for comparing information from the cerebrum with sensory feedback from the periphery through the spinal cord.
- cerebral aqueduct
connection of the ventricular system between the third and fourth ventricles located in the midbrain.
- cerebral cortex
Outer gray matter covering the forebrain, marked by wrinkles and folds known as gyri and sulci.
- cerebral hemisphere
One half of the bilaterally symmetrical cerebrum.
- cerebrospinal fluid (CSF)
Circulatory medium within the CNS that is produced by ependymal cells in the choroid plexus filtering the blood.
- cerebrum
Region of the adult brain that develops from the telencephalon and is responsible for higher neurological functions such as memory, emotion, and consciousness.
- ceruminous gland
Wax producing gland in the ear canal.
- cervical
Neck
- cervical vertebrae
Seven vertebrae numbered as C1–C7 that are located in the neck region of the vertebral column.
- channel protein
Membrane-spanning protein that has an inner pore which allows the passage of one or more substances (a form of facilitated diffusion).
- chemoreceptor
Sensory receptor cell that is sensitive to chemical stimuli, such as in taste, smell, or pain.
- cholecystokinin
A hormone secreted by enteroendocrine cells of the duodenum in response amino acids, fatty acids and HCl. Stimulate gall bladder contraction (release of stored bile).
- cholesterol
Chemically, a type of steroid, cholesterol is a component of cell membranes and a precursor of some important vitamins and hormones.
- cholinergic
Synapse at which acetylcholine is released and binds to the nicotinic or muscarinic receptor.
- chondroblast
Cell responsible for forming new cartilage.
- chondrocyte
cartilage cells
- choroid
Highly vascular tissue in the wall of the eye that supplies the outer retina with blood.
- choroid plexus
Specialized structures containing ependymal cells lining blood capillaries that filter blood to produce CSF in the four ventricles of the brain.
- chromatin
Substance consisting of DNA and associated proteins.
- chromosome
A long DNA molecule, combined with proteins that contains a number of genes. The normal chromosome compliment is 23 pairs of homologous chromosomes, one each from mother and father.
- cilia
Small appendage on certain cells formed by microtubules and modified for movement of materials across the cellular surface (singular = cilium).
- ciliary body
Smooth muscle structure on the interior surface of the iris that controls the shape of the lens through the zonule fibres
- circumduction
Circular motion of the arm, thigh, hand, thumb, or finger that is produced by the sequential combination of flexion, abduction, extension, and adduction.
- clavicle
Collarbone; elongated bone that articulates with the manubrium of the sternum medially and the acromion of the scapula laterally.
- clotting factor
(Also, coagulation factors) group of 12 identified substances active in coagulation.
- coagulation factor
See clotting factor.
- coccyx
Lowest part of the vertebral column; 'tailbone'
- cochlea
Auditory portion of the inner ear containing structures to transduce sound stimuli.
- cochlear duct
(Also scala media) space within the auditory portion of the inner ear that contains the organ of Corti and is adjacent to the scala tympani and scala vestibuli on either side.
- collagen
The most abundant of three protein fibres found in the extracellular matrix of connective tissues.
- colon
Portion of the large intestine.
- compact bone
Dense osseous tissue that can withstand compressive forces.
- compound
A substance composed of two or more different elements joined by chemical bonds.
- concave
Hollowed or rounded inward, like the inside of a bowl. Opposite of convex.
- concentration gradient
Difference in the concentration of a substance between two regions.
- condyloid joint
Synovial joint in which the shallow depression at the end of one bone receives a rounded end from a second bone or a rounded structure formed by two bones; found at the metacarpophalangeal joints of the fingers or the radiocarpal joint of the wrist; functionally classified as a biaxial joint.
- cone
One of the two types of receptor cells in the retina that is specialized for color vision through the use of three photopigments distributed through three separate populations of cells.
- connective tissue
Type of tissue that serves to hold in place, connect, and integrate the body’s organs and systems.
- connective tissue proper
Connective tissue containing a viscous matrix, fibers, and cells.
- continuous conduction
Slow propagation of an action potential along an unmyelinated axon owing to voltage-gated Na+ channels located along the entire length of the cell membrane.
- contractility
Ability to shorten (contract) forcibly.
- contralateral
Opposite side of the body.
- control centre
Compares values to their normal range; deviations cause the activation of an effector.
- convex
Having an outline or surface curved like the outside of a circle or sphere.
- coracobrachialis
Muscle that abducts the arm.
- cornea
Fibrous covering of the anterior region of the eye that is transparent so that light can pass through it.
- coronal plane
See frontal plane
- costal cartilage
Hyaline cartilage structure attached to the anterior end of each rib that provides for either direct or indirect attachment of most ribs to the sternum.
- covalent bond
Chemical bond in which two atoms share electrons, thereby completing their valence shells.
- cranial
Referring to the head. Also see superior.
- cranial cavity
Division of the posterior (dorsal) cavity that houses the brain.
- cranial nerve
One of twelve nerves connected to the brain that are responsible for sensory or motor functions of the head and neck.
- craniosacral system
Alternate name for the parasympathetic division of the autonomic nervous system that is based on the anatomical location of central neurons in brain-stem nuclei and the lateral horn of the sacral spinal cord; also referred to as craniosacral outflow.
- creatine phosphate
Phosphagen used to store energy from ATP and transfer it to muscle.
- crista ampullaris
Sense organ that responds to rotational movement (dynamic equilibrium), contained in each ampulla.
- crus
The portion of the lower limb between the knee and the ankle.
- cupula
Specialized structure within the base of a semicircular canal that bends the stereocilia of hair cells when the head rotates by way of the relative movement of the enclosed fluid.
- cutaneous
Skin.
- cytoplasm
Internal material between the cell membrane and nucleus of a cell, mainly consisting of a water-based fluid called cytosol, within which are all the other organelles and cellular solute and suspended materials.
- cytosol
Clear, semi-fluid medium of the cytoplasm, made up mostly of water.
- decussate
Cross or intersect like an 'X'.
- deep
(In anatomy) describes a position farther from the surface of the body.
- dehydration synthesis
Chemical reaction in which reactants combine to form a new compound, with one reactant gives up an atom of hydrogen and another reactant gives up a hydroxyl group (OH).
- deltoid
Shoulder muscle that abducts the arm as well as flexes and medially rotates it, and extends and laterally rotates it.
- dendrite
One of many branchlike processes that extends from the neuron cell body and functions as a contact for incoming signals (synapses) from other neurons or sensory cells.
- dendritic cell
A monocyte-derived phagocytic cell, function as antigen-presenting cells in the immune system.
- dens
Bony projection (odontoid process) that extends upward from the body of the C2 (axis) vertebra.
- dense body
Sarcoplasmic structure that attaches to the sarcolemma and shortens the muscle as thin filaments slide past thick filaments.
- density
Mass per unit volume.
- deoxyribonucleic acid (DNA)
Deoxyribose-containing nucleic acid that stores genetic information.
- depolarization
Change in a cell membrane potential from rest toward zero.
- depression
Downward (inferior) motion of the scapula or mandible.
- dermal papilla
(Plural = dermal papillae) extension of the papillary layer of the dermis that increases surface contact between the epidermis and dermis.
- dermis
Layer of skin between the epidermis and hypodermis, composed mainly of connective tissue and containing blood vessels, hair follicles, sweat glands, and other structures.
- descending tract
Central nervous system fibers carrying motor commands from the brain to the spinal cord or periphery.
- desmosome
Cell structure that anchors the ends of cardiac muscle fibers to allow contraction to occur.
- diaphragm
Skeletal muscle that separates the thoracic and abdominal cavities and is dome-shaped at rest.
- diaphysis
Tubular shaft that runs between the proximal and distal ends of a long bone.
- diarthrosis
Freely mobile joint.
- diencephalon
Region of the adult brain that retains its name from embryonic development and includes the thalamus and hypothalamus.
- diffusion
Movement of a substance from an area of higher concentration to one of lower concentration.
- digit
Finger or toe.
- dilation
Becoming wider, larger or more open.
- diploë
Layer of spongy bone, that is sandwiched between two the layers of compact bone found in flat bones.
- dipole
Molecule with a negatively charged portion separated from a positively charged portion.
- disaccharide
Molecule formed of a pair of monosaccharides; important to human physiology are sucrose, lactose and maltose.
- dissipate
Scatter or break up.
- distal
Describes a position in a limb that is farther from the point of attachment or the trunk of the body.
- dorsal
See posterior
- dorsal cavity
Posterior body cavity that houses the brain and spinal cord; also referred to the posterior body cavity.
- dorsal root ganglion
Sensory ganglion attached to the posterior nerve root of a spinal nerve.
- dorsiflexion
Movement at the ankle that brings the top of the foot toward the anterior leg.
- dura mater
Tough, fibrous, outer layer of the meninges that is attached to the inner surface of the cranium and vertebral column and surrounds the entire CNS.
- dural sinus
Any of the venous structures surrounding the brain, enclosed within the dura mater, which drain blood from the CNS to the common venous return of the jugular veins.
- dynamic equilibrium
Modality of equilibrium relating to rotational movement of the head.
- ear ossicle
One of three small bones located in the middle ear cavity that serve to transmit sound vibrations to the inner ear.
- eccrine sweat gland
Type of sweat gland that is common throughout the skin surface; it produces a hypotonic sweat for thermoregulation.
- effector
Organ that can cause a change in a value.
- effort
The pulling or pushing force applied to a lever; in lever system in the body, the effort is a muscle with force applied at the insertion.
- effort arm
Distance measured from the fulcrum to the effort (e.g. muscle insertion).
- elastic cartilage
Type of cartilage, with elastin as the major protein, characterized by rigid support as well as elasticity.
- elastic fibre
Fibrous protein within connective tissue that contains a high percentage of the protein elastin that allows the fibers to stretch and return to original size.
- elasticity
Ability to stretch and rebound.
- elastin
One of three protein fibres found in connective tissues.
- electrocardiogram (ECG or EKG)
Surface recording of the electrical activity of the heart that can be used for diagnosis of irregular heart function.
- electrolyte
A solution containing ions; sometimes referring to ions themselves.
- electron
A subatomic particle having a negative charge and nearly no mass; found orbiting the atom’s nucleus.
- electron shell
Area of space a given distance from an atom’s nucleus in which electrons are grouped.
- electronegative
The tendency of an atom to attract electrons in a covalent bond.
- eleiden
Clear protein-bound lipid found in the stratum lucidum that is derived from keratohyalin and helps to prevent water loss.
- element
A substance that cannot be created or broken down by ordinary chemical means
- elevation
Upward (superior) motion of the scapula or mandible.
- ellipsoid joint
See condyloid joint
- embryo
Developing human during weeks 3–8.
- emulsify
Process of forming an emulsion.
- emulsion
Combination of two or more unmixable liquids where one liquid contains a dispersion of the other liquids (often as tiny droplets).
- encapsulated ending
Configuration of a sensory receptor neuron with dendrites surrounded by specialized structures to aid in transduction of a particular type of sensation, such as the lamellated corpuscles in the deep dermis and subcutaneous tissue.
- endochondral ossification
Process in which bone forms by replacing hyaline cartilage.
- endocrine
Tissue or organ that secretes hormones into the blood and lymph without ducts such that they may be transported to organs distant from the site of secretion.
- endocytosis
Import of material into the cell by formation of a membrane-bound vesicle.
- endolymph
Extracellular fluid of the inner ear, lying within the membranous labyrinth.
- endomembrane system
Set of cellular organelles that often work together to produce, package and export certain products.
- endomysium
Loose, and well-hydrated connective tissue covering each muscle fibre in a skeletal muscle.
- endoplasmic reticulum (ER)
Cellular organelle that consists of interconnected membrane-bound tubules, which may or may not be associated with ribosomes (rough type or smooth type, respectively).
- endosteum
Delicate membranous lining of a bone’s medullary cavity.
- endothelium
Layer of smooth, simple squamous epithelium that lines the endocardium and blood vessels.
- enteric nervous system
Neural tissue associated with the digestive system that is responsible for nervous control through autonomic connections.
- enzyme
Molecule (usually a protein) that catalyzes chemical reactions.
- ependymal cell
Glial cell type that filters blood at the choroid plexus.
- epidermis
outermost tissue layer of the skin
- epigastric region
Abdominopelvic region located in the central superior area below the xiphoid process.
- epimysium
Loose, and well-hydrated connective tissue covering each muscle fiber in a skeletal muscle.
- epinephrine
Signaling molecule released from the adrenal medulla into the bloodstream as part of the sympathetic response.
- epiphyseal line
completely ossified remnant of the epiphyseal plate
- epiphyseal plate
(Also, growth plate) sheet of hyaline cartilage in the metaphysis of an immature bone; replaced by bone tissue as the organ grows in length.
- epiphysis
Wide section at each end of a long bone; filled with spongy bone and red marrow.
- epithalamus
Region of the diecephalon containing the pineal gland.
- epithelial
Type of tissue that serves primarily as a covering or lining of body parts, protecting the body; it also functions in absorption, transport, and secretion.
- erector spinae group
Large muscle mass of the back; primary extensor of the vertebral column.
- erythrocyte
Red blood cell.
- ethmoid bone
Unpaired bone that forms the roof and upper, lateral walls of the nasal cavity, portions of the floor of the anterior cranial fossa and medial wall of orbit, and the upper portion of the nasal septum.
- eukaryotic
One of two major divisions of living things (or their cells) that have membrane-bound nuclei and other organelles, and can form large complex organisms (including all animals, plants, fungi). By contrast, bacteria are prokaryotic.
- Eustachian tube
(Also pharyngotympanic tube) tube linking the pharynx and middle ear, important for equalizing air pressure in the middle ear.
- eversion
Foot movement involving the intertarsal joints of the foot in which the bottom of the foot is turned laterally, away from the midline.
- excitability
ability to undergo neural stimulation
- excitation-contraction coupling
The sequence of events from motor neuron signaling to a skeletal muscle fiber to contraction of the fiber’s sarcomeres
- exocytosis
Export of a substance out of a cell by formation of a membrane-bound vesicle.
- extensibility
Ability to lengthen (extend).
- extension
Movement that increases the angle of a joint.
- external ear
Structures on the lateral surface of the head, including the auricle and the ear canal back to the tympanic membrane.
- external intercostal
Superficial intercostal muscles that raise the rib cage.
- external oblique
Superficial abdominal muscle with fascicles that extend inferiorly and medially.
- exteroceptor
Sensory receptor that is positioned to interpret stimuli from the external environment, such as photoreceptors in the eye or somatosensory receptors in the skin.
- extracellular fluid (ECF)
Fluid outside cells (plasma or interstitial fluid).
- extraocular
One of six muscles originating out of the bones of the orbit and inserting into the surface of the eye which are responsible for moving the eye.
- facial bones
Fourteen bones that support the facial structures and form the upper and lower jaws and the hard palate.
- facilitated diffusion
Diffusion of a substance with the aid of a membrane protein.
- fallopian tube
See uterine tube
- false ribs
Vertebrochondral ribs 8–12 whose costal cartilage either attaches indirectly to the sternum via the costal cartilage of the next higher rib or does not attach to the sternum at all.
- fascicle
Bundle of muscle fibres within a skeletal muscle
- fatty acid
Consisting of a carboxyl group (COOH) and an unbranched hydrocarbon chain. A non-polar component of all lipids.
- femur
Thigh bone; the single bone of the thigh.
- fetus
Developing human during the time from the end of the embryonic period (week 9) to birth.
- FG fibres
Muscle fibres that produce quick, strong contractions, primarily using anaerobic respiration.
- fibroblast
Most abundant cell type in connective tissue, secretes protein fibers and matrix into the extracellular space.
- fibrocartilage
Tough form of cartilage, made of thick bundles of collagen fibers embedded in chondroitin sulfate ground substance.
- fibrocyte
Mature, less active form of a fibroblast.
- fibrous connective tissue
Dense connective tissue (irregular or regular) consisting of a dense array of collagen and reticular fibres.
- fibrous joint
Joint where the articulating areas of the adjacent bones are connected by fibrous connective tissue.
- fibrous tunic
Outer layer of the eye primarily composed of connective tissue known as the sclera and cornea.
- fibula
Thin, non-weight-bearing bone found on the lateral side of the leg.
- first-class lever
A lever system in which the effort and resistance are applied on opposite sides of the fulcrum.
- fixator
Synergist that assists an agonist by preventing or reducing movement at another joint, thereby stabilizing the origin of the agonist.
- flexion
Movement that decreases the angle of a joint.
- floating ribs
Vertebral ribs 11–12 that do not attach to the sternum or to the costal cartilage of another rib.
- fontanelle
Expanded area of fibrous connective tissue that separates the brain case bones of the skull prior to birth and during the first year after birth.
- foramen
General anatomical term for a hole or opening (usually in bone. Plural = foramina
- fourth ventricle
The portion of the ventricular system that is in the region of the brain stem and opens into the subarachnoid space through the median and lateral apertures.
- fovea
Exact centre of the retina at which visual stimuli are focused for maximal acuity, where the retina is thinnest, at which there is nothing but photoreceptors.
- free nerve ending
Configuration of a sensory receptor neuron with dendrites in the connective tissue of the organ, such as in the dermis of the skin, that are most often sensitive to chemical, thermal, and mechanical stimuli.
- frontal bone
Unpaired bone that forms forehead, roof of orbit, and floor of anterior cranial fossa.
- frontal plane
Two-dimensional, vertical plane that divides the body or organ into anterior and posterior portions.
- fulcrum
The point around which a lever rotates.
- functional group
Group of atoms linked by strong covalent bonds that tends to behave as a distinct unit in chemical reactions with other atoms.
- G protein
Ubiquitous family of proteins that generally act as switches (turning on or off chemical processes) by transmitting signals from outside to inside cells.
- gamete
Haploid reproductive cell (egg or sperm in humans) that contributes genetic material to form an offspring.
- ganglion
Localized collection of neuron cell bodies in the peripheral nervous system.
- ganglion cell
Neuron of the retina that projects along the second cranial nerve.
- gap junction
Structures between cardiac muscle cells that form channels between adjacent cardiac muscle fibres that allow the depolarizing current to travel between adjacent cells.
- gastrocnemius
Most superficial muscle of the calf.
- germ cell
Cell that gives rise to a gamete.
- girdle
An encircling or confining structure; in anatomy, the pectoral or pelvic girdle.
- glenohumeral joint
Shoulder joint; formed by the articulation between the glenoid cavity of the scapula and the head of the humerus.
- glenoid cavity
(Also, glenoid fossa) shallow depression located on the lateral scapula, between the superior and lateral borders.
- glenoid fossa
See glenoid cavity
- glossopharyngeal nerve
Ninth cranial nerve; responsible for contraction of muscles in the tongue and throat and for part of the sense of taste, as well as causing saliva production.
- glucose
Monosaccharide commonly used as energy in the body (substrate for glycolysis).
- gluteal group
Muscle group that extends, flexes, rotates, adducts, and abducts the femur.
- gluteus maximus
Largest of the gluteus muscles that extends the femur.
- gluteus medius
Muscle deep to the gluteus maximus that abducts the femur at the hip.
- glycerol
Molecule that forms the 'backbone' of many lipids, including triglycerides.
- glycocalyx
Coating of carbohydrate molecules that surrounds the cell membrane.
- glycogen
Polysaccharide used as a storage form of glucose in the liver.
- glycolipid
A molecule composed of carbohydrate and lipid components.
- glycolysis
Series of metabolic reactions that breaks down glucose into pyruvate and produces ATP.
- glycoprotein
Protein that has one or more carbohydrates attached.
- Golgi apparatus
Cellular organelle formed by a series of flattened, membrane-bound sacs that functions in protein modification, tagging, packaging, and transport.
- gomphosis
Type of fibrous joint in which the root of a tooth is anchored into its bony jaw socket by strong periodontal ligaments.
- gracilis
Muscle that adducts the thigh and flexes the leg at the knee.
- graded potential
Change in the membrane potential that varies in size, depending on the size of the stimulus that elicits it.
- gray matter
Regions of the nervous system containing cell bodies of neurons with few or no myelinated axons; actually may be more pink or tan in color, but called gray in contrast to white matter.
- greater sciatic notch
Large, U-shaped indentation located on the posterior margin of the ilium, superior to the ischial spine.
- ground substance
Fluid or semi-fluid portion of the matrix.
- growth hormone (GH)
(Also, somatotropin) anterior pituitary hormone that promotes tissue building and influences nutrient metabolism.
- gustatory receptor cell
Sensory cells in the taste bud that transduce the chemical stimuli of gustation.
- gyrus
Ridge formed by convolutions on the surface of the cerebrum or cerebellum.
- hair bulb
Structure at the base of the hair root that surrounds the dermal papilla.
- hair cells
Mechanoreceptor cells found in the inner ear that transduce stimuli for the senses of hearing and balance.
- hair follicle
Cavity or sac from which hair originates.
- hair root
Part of hair that is below the epidermis anchored to the follicle.
- hallux
Big toe
- hamstring group
Three long muscles on the back of the upper leg.
- Haversian canal
See central canal
- Haversian system
See osteon
- Haversion system
See osteon
- helicotrema
Tip of the cochlea where the scale vestibuli meets the scala tympani.
- hematopoiesis
See hemopoeisis
- hemoglobin
Oxygen-carrying protein in erythrocytes (red blood cells).
- hemopoiesis
(Also, hematopoiesis) production of the formed elements of blood.
- hindbrain
Posterior region of the adult brain that develops from the rhombencephalon and includes the pons, medulla oblongata, and cerebellum.
- hinge joint
Synovial joint at which the convex surface of one bone articulates with the concave surface of a second bone; includes the elbow, knee, ankle, and interphalangeal joints; functionally classified as a uniaxial joint.
- histamine
Vasoactive (active on blood vessels) mediator in granules of mast cells and is the primary cause of allergies and anaphylactic shock.
- histology
Microscopic study of tissue architecture, organization, and function.
- homeostasis
Steady state of body systems that living organisms maintain.
- homogeneous
Condition in which solute molecules are distributed equally in a solution.
- hormone
Secretion of an endocrine organ that travels via the bloodstream or lymphatics to induce a response in target cells or tissues in another part of the body.
- host
(in immunology) referring to the organism in, or on, which a pathogen lives.
- humerus
Single bone of the upper arm.
- hyaline cartilage
Most common type of cartilage, smooth and made of short collagen fibers embedded in a chondroitin sulfate ground substance.
- hydrocarbon
Organic compound, or portion of a molecule, composed entirely of hydrogen and carbon atoms.
- hydrogen bond
Dipole-dipole bond in which a hydrogen atom covalently bonded to an electronegative atom is weakly attracted to a second electronegative atom.
- hydrolysis
Chemical reaction in which a molecule water is split into H and OPH, thereby breaking a bond and severing a compound.
- hydrophilic
"Water loving"; a molecule or portion thereof that is polar and therefore water soluble.
- hydrophobic
"Water hating"; a molecule or portion thereof that is nonpolar and therefore water insoluble.
- hydroxyapatite
A form of calcium phosphate mineral found in bones (also hydroxylapatite)
- hydroxyl
A functional group, OH, present in many organic compounds including alcohols.
- hyoid bone
Small, U-shaped bone located in upper neck that does not contact any other bone.
- hyperextension
Excessive extension of joint, beyond the normal range of movement.
- hyperflexion
Excessive flexion of joint, beyond the normal range of movement.
- hyperpolarization
Change in cell membrane potential below resting potential (<-70mV).
- hypertonic
Describes a solution concentration that is higher than a reference concentration.
- hypertrophy
Addition of structural proteins to muscle fibres.
- hypochondriac region
Abdominopelvic region (left or right) located under the lowest ribs in the superior corners of the abdominopelvic cavity.
- hypodermis
Connective tissue connecting the integument to the underlying bone and muscle.
- hypogastric region
Central inferior abdominopelvic region.
- hypothalamus
Region of the brain inferior to the thalamus that functions in neural and endocrine signaling, temperature regulation and control of the autonomic nervous system.
- hypotonic
Describes a solution concentration that is lower than a reference concentration.
- iliac region
Abdominopelvic region in the left or right inferior corners of the abdomen, below the hip bone.
- iliacus
Muscle that, along with the psoas major, makes up the iliopsoas.
- iliopsoas group
Muscle group consisting of iliacus and psoas major muscles, that flexes the thigh at the hip, rotates it laterally, and flexes the trunk of the body onto the hip.
- ilium
Superior portion of the hip bone.
- incus
Ossicle of the middle ear (popularly called the anvil) that connects the malleus to the stapes.
- inferior
Describes a position below or lower than another part of the body proper; near or toward the tail (in humans, the coccyx, or lowest part of the spinal column); also referred to as caudal.
- inferior articular process
Bony process that extends downward from the vertebral arch of a vertebra that articulates with the superior articular process of the next lower vertebra.
- inferior colliculus
Half of the midbrain tectum that is part of the brain stem auditory pathway.
- inferior vena cava
Large systemic vein that returns blood to the heart from the inferior portion of the body.
- infraspinatus
Muscle that laterally rotates the arm.
- inner ear
Structure within the temporal bone that contains the sensory apparati of hearing and balance.
- inner synaptic layer
Layer in the retina where bipolar cells connect to ganglion cells.
- innermost intercostal
The deepest intercostal muscles that draw the ribs together.
- inorganic compound
A substance that does not contain both carbon and hydrogen.
- insertion
End of a skeletal muscle that is attached to the structure (usually a bone) that is moved when the muscle contracts.
- insulin
Hormone that enhances the cellular uptake and utilization of glucose, thereby decreasing blood glucose levels.
- integral protein
Membrane-associated protein that spans the entire width of the lipid bilayer.
- integumentary system
Skin and its accessory structures.
- intermediate
Describes a position between a more medial and a more lateral structure.
- internal intercostal
Muscles the intermediate intercostal muscles that draw the ribs together.
- internal oblique
Flat, intermediate abdominal muscle with fascicles that run perpendicular to those of the external oblique.
- interoception
Sensation of stimuli from internal organs.
- interoceptor
Sensory receptor that is positioned to interpret stimuli from internal organs, such as stretch receptors in the wall of blood vessels.
- interosseous membrane
Wide sheet of fibrous connective tissue that fills the gap between two parallel bones, forming a syndesmosis; found between the radius and ulna of the forearm and between the tibia and fibula of the leg.
- interphalangeal joint
Articulation between adjacent phalanx bones of the hand or foot digits.
- interstitial fluid (IF)
Extracellular fluid in the small spaces between cells not contained within blood vessels.
- intervertebral disc
Structure located between the bodies of adjacent vertebrae that strongly joins the vertebrae; provides padding, weight bearing ability, and enables vertebral column movements.
- intracellular fluid (ICF)
Fluid inside cells.
- intramembranous ossification
Process by which bone forms directly from mesenchymal tissue.
- inversion
Foot movement involving the intertarsal joints of the foot in which the bottom of the foot is turned toward the midline.
- involuntary
(In physiology) though under nervous control (usually from the brain), control is not conscious.
- ion
Atom with an overall positive or negative charge. Many function as electrolytes.
- ionic bond
Attraction between an anion and a cation.
- iris
Coloured portion of the anterior eye that surrounds the pupil.
- ischial tuberosity
Large, roughened protuberance that forms the posteroinferior portion of the hip bone; weight-bearing region of the pelvis when sitting.
- ischium
Superior portion of the hip bone.
- isotonic
Describes a solution concentration that is the same as a reference concentration.
- joint
Site at which two or more bones or bone and cartilage come together (articulate).
- joint cavity
Space enclosed by the articular capsule of a synovial joint that is filled with synovial fluid and contains the articulating surfaces of the adjacent bones.
- jugular vein
One of a pair of major veins located in the neck region that flows parallel to the common carotid artery that is more or less its counterpart; primarily drains blood from the brain, receives the superficial facial vein, and empties into the subclavian vein.
- keratin
Type of structural protein that gives skin, hair, and nails its hard, water-resistant properties.
- keratinocyte
Cell that produces keratin and is the most predominant type of cell found in the epidermis.
- keratohyalin
Granulated protein found in the stratum granulosum.
- kinesthesia
Sense of body movement based on sensations in skeletal muscles, tendons, joints, and the skin.
- kinetic energy
Energy that matter possesses because of its motion.
- lacrimal duct
Duct in the medial corner of the orbit that drains tears into the nasal cavity.
- lacrimal gland
Gland lateral to the orbit that produces tears to wash across the surface of the eye.
- lactic acid
(Also, lactate) a three-carbon acid formed as a product of lactic acid fermentation, and used as a substrate in gluconeogenesis.
- lacuna
(Plural= lacunae) small spaces in bone or cartilage tissue that cells occupy.
- lamellae
Concentric rings of calcified matrix that form an osteon.
- lamellated corpuscle
Encapsulated mechanoreceptor cell found in the skin that responds to pressure and touch.
- Langerhans cell
Specialized dendritic cell found in the stratum spinosum that functions as a macrophage.
- larynx
cartilaginous structure that produces the voice, prevents food and beverages from entering the trachea, and regulates the volume of air that enters and leaves the lungs
- latch-bridge
Subset of a cross-bridge in which actin and myosin remain locked together.
- lateral
Describes the side or direction toward the side of the body.
- lateral geniculate nucleus
Thalamic target of the ganglion cells that projects to the visual cortex
- lateral horn
Region of the spinal cord gray matter in the thoracic, upper lumbar, and sacral regions that is the central component of the sympathetic division of the autonomic nervous system.
- lateral ventricles
Portions of the ventricular system that are in the region of the cerebrum.
- latissimus dorsi
Broad, triangular axial muscle located on the inferior part of the back.
- leakage channel
Ion channel (facilitated diffusion) that opens randomly and is not gated to a specific event, also known as a non-gated channel.
- lens
Component of the eye that focuses light on the retina.
- leukocyte
White blood cell.
- lever
Simple machine consisting of a beam or rigid rod (bone) pivoted at a fixed hinge, or fulcrum (joint).
- ligament
Strong connective tissue bands that hold the bones at a moveable joint together.
- ligand-gated channel
A channel protein (facilitated diffusion) that is activated (opens) when a molecule (such as a neurotransmitter) binds to it.
- limbic system
Structures at the edge (limit) of the boundary between the forebrain and hindbrain that are most associated with emotional behavior and memory formation.
- linea alba
Long, linear muscle that extends along the middle of the trunk.
- lipid
Class of nonpolar organic compounds built from hydrocarbons and distinguished by the fact that they are not soluble in water.
- load
see resistance
- longitudinal plane
See parasagittal plane
- longus
Long
- lumbar
Lower back, below the ribs.
- lumbar region
Left or right central abdominopelvic region.
- lumbar vertebrae
Five vertebrae numbered as L1–L5 that are located in lumbar region (lower back) of the vertebral column.
- lymph
Fluid contained within the lymphatic system, consisting of interstitial fluid, leukocytes (white blood cells), proteins (including antibodies) and fats.
- lymphocyte
White blood cell characterized by a large nucleus and small rim of cytoplasm.
- lysosome
Membrane-bound cellular organelle originating from the Golgi apparatus and containing digestive enzymes.
- macromolecule
large molecule formed by covalent bonding; classes of macromolecule discussed in this course include carbohydrates, lipids, proteins and nucleic acids.
- macrophage
Ameboid (irregular outline with peripheral projections) phagocyte found in several tissues throughout the body.
- macula
Enlargement at the base of a semicircular canal at which transduction of equilibrium stimuli takes place within the ampulla.
- macula lutea
A pigmented area in the middle of the retina, contains the fovea.
- malleus
Ossicle of the middle ear (popularly called the hammer) that is directly attached to the tympanic membrane.
- mammary gland
Milk producing gland in mammals.
- mandible
Unpaired bone that forms the lower jaw bone; the only moveable bone of the skull.
- manubrium
Expanded, superior portion of the sternum.
- mass number
Sum of the number of protons and neutrons in the nucleus of an atom.
- mast cell
Cell found in the skin and the lining of body cells that contains cytoplasmic granules with vasoactive mediators such as histamine.
- mastoid antrum
An air space in the tympanic bone, posterior to (and connected with) the middle ear.
- mastoid process
Large bony prominence on the inferior, lateral skull, just behind the earlobe.
- matrix
(In connective tissue) extracellular material which is produced by the cells embedded in it, containing ground substance and fibres.
- matter
Scientifically, a physical substance; that which occupies space and has mass
- maxilla
See maxillary bone
- maxillary bone
(Also, maxilla) paired bones that form the upper jaw and anterior portion of the hard palate.
- maximus
Largest
- mechanically gated channel
Ion channel protein (facilitated diffusion) that opens when a physical event directly affects the structure of the protein.
- mechanoreceptor
Receptor cell that transduces mechanical stimuli into an electrochemical signal.
- medial
Describes the middle or direction toward the middle of the body.
- mediastinum
A central compartment in the thoracic cavity located intermediate to the left and right pleural cavities.
- medulla oblongata
Lowest (most inferior) part of the brain, controlling many autonomic functions including heart rate, breathing, and digestion.
- medullary cavity
Hollow region of the diaphysis; filled with yellow marrow.
- Meissner corpuscle
(Also, tactile corpuscle) receptor in the skin that responds to light touch.
- melanin
Pigment that determines the color of hair and skin.
- melanocyte
Cell found in the stratum basale of the epidermis that produces the pigment melanin.
- membrane potential
Distribution of charge across the cell membrane, based on the charges of ions.
- meninges
Protective outer coverings of the CNS composed of connective tissue.
- meniscus
See articular disc
- Merkel cell
Receptor cell in the stratum basale of the epidermis that responds to the sense of touch.
- Merkel cells
Receptor cell in the stratum basale of the epidermis that responds to the sense of touch.
- merocrine gland
Gland whose secretions are excreted by exocytosis.
- mesenchyme
Embryonic tissue from which connective tissue cells derive.
- metabolism
Sum of all catabolic and anabolic reactions that take place in the body.
- metacarpal
One of the five long bones that form the palm of the hand; numbered 1–5, starting on the lateral (thumb) side of the hand.
- metatarsal
One of the five elongated bones that forms the anterior half of the foot; numbered 1–5, starting on the medial side of the foot.
- methyl
A chemical function group, CH3, a component of fatty acids.
- micturition
Also called urination or voiding.
- midbrain
Middle region of the adult brain that develops from the mesencephalon.
- middle ear
Space within the temporal bone between the ear canal and bony labyrinth where the ossicles amplify sound waves from the tympanic membrane to the oval window.
- midsagittal plane
A sagittal plane on the midline, dividing the body into equal left and right halves (also medial plane).
- mitochondrion
One of the cellular organelles bound by a double lipid bilayer that function primarily in the production of cellular energy (ATP).
- mitosis
Division of genetic material, during which the cell nucleus breaks down and two new, fully functional, nuclei are formed. Usually immediately followed by cytokinesis (cell division).
- molecule
Two or more atoms covalently bonded together.
- monocytes
Precursor to macrophages and dendritic cells seen in the blood.
- monomer
A molecule that can react with other similar monomers to form a polymer; e.g. amino acids combine to form proteins.
- monosaccharide
Five or six-carbon molecule that are monomers of carbohydrates; examples include glucose, fructose, galactose, ribose and deoxyribose.
- motor end-plate
The sarcolemma of muscle fibre at the neuromuscular junction, with receptors for the neurotransmitter acetylcholine.
- multiaxial
Type of diarthrosis; a joint that allows for movements within three planes (three axes).
- multiaxial joint
Type of diarthrosis; a joint that allows for movements within three planes (three axes).
- multicellular
Consisting of more than one cell (as opposed organisms such as bacteria which are unicellular).
- multipolar
Shape of a neuron that has multiple processes—the axon and two or more dendrites.
- multipotent
Describes the condition of being able to differentiate into different types of cells within a given cell lineage or small number of lineages, such as a red blood cell or white blood cell.
- muscle tone
Low levels of muscle contraction that occur when a muscle is not producing movement.
- myelin
Lipid-rich insulating substance surrounding the axons of many neurons, allowing for faster transmission of electrical signals.
- myelin sheath
Lipid-rich layer of insulation that surrounds an axon, formed by oligodendrocytes in the CNS and Schwann cells in the PNS; facilitates the transmission of electrical signals.
- myocyte
Muscle cell (also muscle fibre).
- myofibril
Long, cylindrical organelle that runs parallel within the muscle fibre and contains the sarcomeres.
- myosin
Protein that makes up most of the thick cylindrical myofilament within a sarcomere muscle fibre.
- NAD+
Electron acceptor that carries electrons from glycolysis and citric acid cycle to the electron transport chain (or supplies electrons during lactic acid fermentation). NADH is the higher energy form, carrying two electrons.
- negative feedback
Homeostatic mechanism that tends to stabilize an upset in the body’s physiological condition by preventing an excessive response to a stimulus, typically as the stimulus is removed.
- nerve
Cord-like bundle of axons located in the peripheral nervous system that transmits sensory input and response output to and from the central nervous system.
- neural tunic
Layer of the eye that contains nervous tissue, namely the retina.
- neuroglia
Supportive neural cells.
- neuromuscular junction
Synapse between the axon terminal of a motor neuron and the section of the membrane of a muscle fiber with receptors for the acetylcholine released by the terminal.
- neurons
Excitable neural cell that transfer nerve impulses.
- neurotransmitter
Chemical signal that is released from the synaptic end bulb of a neuron to cause a change in the target cell.
- neutron
A heavy subatomic particle having no electrical charge and found in the atom’s nucleus.
- nociception
Sensing pain.
- nociceptor
Receptor cell that senses pain stimuli.
- node of Ranvier
Gap between two myelinated regions of an axon, allowing for strengthening of the electrical signal as it propagates down the axon.
- nonpolar
Opposite of polar; molecule with electrons that are relatively equally shared in covalent bonds.
- norepinephrine
Signaling molecule released as a neurotransmitter by most postganglionic sympathetic fibres as part of the sympathetic response, or as a hormone into the bloodstream from the adrenal medulla.
- nuclear envelope
Membrane that surrounds the nucleus; consisting of a double lipid-bilayer.
- nuclear pore
One of the small, protein-lined openings found scattered throughout the nuclear envelope.
- nucleolus
Small region of the nucleus that functions in ribosome synthesis.
- nucleotide
Class of organic compounds composed of one or more phosphate groups, a pentose sugar, and a base.
- nucleus (cell)
Cell’s central organelle; contains the cell’s DNA.
- nucleus (nervous tissue)
(In nervous system) a localized collection of neuron cell bodies that are functionally related; a “center” of neural function (plural= nuclei).
- nutrient foramen
Small opening in the middle of the external surface of the diaphysis, through which an artery enters the bone to provide nourishment.
- oblique
At an angle.
- occipital
Unpaired bone that forms the posterior portions of the brain case and base of the skull.
- oculomotor nerve
Third cranial nerve; responsible for contraction of four of the extraocular muscles, the muscle in the upper eyelid, and pupillary constriction.
- olfaction
Referring to the sense of smell.
- olfactory bulb
Central target of the first cranial nerve; located on the ventral surface of the frontal lobe in the cerebrum.
- olfactory epithelium
Region of the nasal epithelium where olfactory neurons are located.
- olfactory sensory neuron
Receptor cell of the olfactory system, sensitive to the chemical stimuli of smell, the axons of which compose the first cranial nerve.
- oligodendrocyte
Glial cell type in the CNS that provides the myelin insulation for axons in tracts.
- opsin
Protein that contains the photosensitive cofactor retinal for phototransduction.
- optic chiasm
Intersect point in the visual system at which medial retina fibres cross to the other side of the brain.
- optic disc
Spot on the retina at which ganglion cell axons leave the eye and blood vessels of the inner retina pass.
- optic nerve
Second cranial nerve, which is responsible visual sensation.
- optic tract
Name for the fibre structure containing axons from the retina posterior to the optic chiasm representing their CNS location.
- orbit
(In anatomy), the openings for eyes in the skull.
- organ
An anatomically distinct structure of the body composed of two or more tissue types.
- organ of Corti
Structure in the cochlea in which hair cells transduce movements from sound waves into electrochemical signals.
- organ system
Group of organs that work together to carry out a particular function.
- organelle
Any of several different types of membrane-enclosed specialized structures in the cell that perform specific functions for the cell.
- organic compound
A substance that contains both carbon and hydrogen.
- organism
Living being that has a cellular structure and that can independently perform all physiologic functions necessary for life.
- origin
End of a skeletal muscle that is attached to another structure (usually a bone) in a fixed position.
- oris
Mouth
- osmoreceptor
Receptor cell that senses differences in the concentrations of bodily fluids on the basis of osmotic pressure.
- osmosis
Diffusion of water molecules down their concentration gradient across a selectively permeable membrane.
- ossicles
Three small bones in the middle ear.
- ossification
(Also, osteogenesis) bone formation.
- ossification centre
Cluster of osteoblasts found in the early stages of intramembranous ossification.
- osteoblast
Cell responsible for forming new bone.
- osteoclast
Cell responsible for resorbing bone.
- osteocyte
Primary cell in mature bone; responsible for maintaining the matrix.
- osteogenesis
See ossification
- osteogenic cell
Undifferentiated cell with high mitotic activity; the only bone cells that divide; they differentiate and develop into osteoblasts.
- osteoid
Uncalcified bone matrix secreted by osteoblasts.
- osteon
(Also, Haversian system) basic structural unit of compact bone; made of concentric layers of calcified matrix.
- otolithic membrane
Gelatinous substance in the utricle and saccule of the inner ear that contains calcium carbonate crystals and into which the stereocilia of hair cells are embedded.
- otoliths
Layer of calcium carbonate crystals located on top of the otolithic membrane.
- outer synaptic layer
Layer in the retina at which photoreceptors connect to bipolar cells.
- oval window
Membrane at the base of the cochlea where the stapes attaches, marking the beginning of the scala vestibuli.
- oviduct
See uterine tube
- oxytocin
Hormone stored in the posterior pituitary gland and important in stimulating uterine contractions in labor, milk ejection during breastfeeding, and feelings of attachment (also produced in males).
- palpebral conjunctiva
Membrane attached to the inner surface of the eyelids that covers the anterior surface of the cornea.
- papilla
For gustation, a bump-like projection on the surface of the tongue that contains taste buds.
- parasagittal plane
A sagittal plane that does not divide the body into equal left and right halves (also longitudinal section).
- parasympathetic division
Division of the autonomic nervous system responsible for restful and digestive functions.
- parenchyma
Functional cells of a gland or organ, in contrast with the supportive or connective tissue of a gland or organ.
- parietal
Facing the body wall.
- parietal bone
Paired bones that form the upper, lateral sides of the skull.
- passive transport
Form of transport across the cell membrane that does not require input of cellular energy.
- patella
Knee cap.
- patellar ligament
Extension of the quadriceps tendon below the patella.
- patellar tendon
See quadriceps tendon
- pathogen
An infectious agent that causes disease, typically a bacterium, virus, fungus, or microscopic parasite.
- pectoral girdle
Shoulder girdle; the set of bones, consisting of the scapula and clavicle, which attaches each upper limb to the axial skeleton.
- pectoralis major
Thick, fan-shaped axial muscle that covers much of the superior thorax.
- pelvic girdle
Hip girdle; consists of a single hip bone, which attaches a lower limb to the sacrum of the axial skeleton.
- peptide
As a molecule, a short chain of amino acids. Also refers to something related to proteins.
- peptide bond
A type of covalent bond occurring between amino acids.
- perforating canal
(Also, Volkmann’s canal) channel that branches off from the central canal and houses vessels and nerves that extend to the periosteum and endosteum.
- pericardial fluid
Fluid found in the pericardium.
- pericardium
Cavity surrounding the heart filled with a lubricating serous fluid that reduces friction as the heart contracts (also, pericardial cavity or cardiac sac).
- perichondrium
Layer of dense irregular connective tissue surrounding cartilage.
- perilymph
Extracellular fluid of the inner ear, lying between the membranous labyrinth and the bony labyrinth.
- perimysium
Connective tissue that bundles skeletal muscle fibres into fascicles within a skeletal muscle.
- periodic table of the elements
An arrangement of the elements in a table according to their atomic number; elements having similar properties because of their electron arrangements compose columns in the table, while elements having the same number of valence shells compose rows in the table. See Appendix I.
- periosteum
Fibrous membrane covering the outer surface of bone and continuous with ligaments.
- peripheral
Describes a position towards the outer edge (periphery) of a structure or organ system.
- peripheral protein
Membrane-associated protein that does not span the width of the lipid bilayer, but is attached peripherally to integral proteins, membrane lipids, or other components of the membrane.
- peristalsis
Muscular contractions and relaxations that propel food through the tubes like the GI tract.
- peritoneum
Serous membrane that lines the abdominopelvic cavity and covers the organs found there.
- phagocytosis
Cell process (a form of endocytosis) in which a cell engulfs and ingests another large particle or cell.
- phalanx
(plural = phalanges) one of the bones that form the fingers or toes.
- pharynx
Throat
- pheromone
A chemical, either secreted or excreted, that produces a social response in other individuals.
- phosphate
Chemical functional group, PO4-, a component of phospholipids and nucleic acids (including ATP).
- phospholipid
An amphipathic lipid molecule containing a phosphate head (polar) and two fatty acid tails (non-polar). The major molecule comprising plasma membranes.
- phosphorylation
addition of one or more phosphate groups to an organic compound
- photoisomerization
Chemical change in the retinal molecule that alters the bonding so that it switches from the 11-cis-retinal isomer to the all-trans-retinal isomer.
- photon
Individual “packet” of light.
- photoreceptor
Receptor cell specialized to respond to light stimuli.
- pia mater
Thin, innermost membrane of the meninges that directly covers the surface of the CNS.
- pinocytosis
Endocytosis of fluid.
- pituitary gland
Bean-sized organ suspended from the hypothalamus that produces, stores, and secretes hormones in response to hypothalamic stimulation (also called hypophysis).
- pivot joint
Synovial joint at which the rounded portion of a bone rotates within a ring formed by a ligament and an articulating bone; functionally classified as uniaxial joint.
- plane
(In anatomy) imaginary two-dimensional surface that passes through the body.
- plane joint
Synovial joint formed between the flattened articulating surfaces of adjacent bones; functionally classified as a multiaxial joint.
- plantar flexion
Foot movement at the ankle in which the heel is lifted off of the ground.
- plasma
An extracellular fluid, the fluid component of blood.
- plasma cell
Differentiated B cell that is actively secreting antibody.
- platelets
(Also, thrombocytes) one of the formed elements of blood that consists of cell fragments broken off from megakaryocytes.
- pleura
Serous membrane that lines the pleural cavity and covers the lungs.
- pleural cavity
The space between the visceral and parietal pleurae.
- pleural fluid
Substance that acts as a lubricant for the visceral and parietal layers of the pleura during the movement of breathing.
- polar
Molecule with regions that have opposite charges resulting from uneven numbers of electrons in the nuclei of the atoms participating in the covalent bond.
- polarity (neurons)
Information flow in one direction.
- pollex
Thumb
- polymer
A molecule formed of many monomers together forming a macromolecule.
- polypeptide
A chain of amino acids, typically fewer than 100.
- polysaccharide
A complex molecule formed of many (up to a thousand or more) monosaccharides; e.g. glycogen, starches, and cellulose.
- pons
Portion of the brainstem connecting the medulla oblongata with the midbrain. Serves as a connection to cerebellum, as well as functions including sleep cycles and the origin of some cranial nerves.
- popliteus
Back of the knee.
- positive feedback
Mechanism that intensifies a change in the body’s physiological condition in response to a stimulus.
- posterior
Describes the back or direction toward the back of the body; also referred to as dorsal.
- posterior cavity
See dorsal cavity
- posterior horn
Gray matter region of the spinal cord in which sensory input arrives, sometimes referred to as the dorsal horn.
- postganglionic fibre
Axon from a ganglionic neuron in the autonomic nervous system that projects to and synapses with the target effector; sometimes referred to as a postganglionic neuron.
- potential energy
Stored energy matter possesses because of the positioning or structure of its components.
- power lever
A lever system that can move a load/resistance with less effort (compared to moving the resistance without a lever system); by definition, the mechanical advantage is greater than one (effort arm > resistance arm).
- preganglionic fibre
Axon from a central neuron in the autonomic nervous system that projects to and synapses with a ganglionic neuron; sometimes referred to as a preganglionic neuron.
- primary active transport
Active transport using carrier proteins that use ATP (powered by the energy obtained through phosphorylation by ATP).
- primary ossification centre
Region, deep in the periosteal collar, where bone development starts during endochondral ossification.
- prime mover
See agonist
- process
In cells, an extension of a cell body; in the case of neurons, this includes the axon and dendrites.
- proliferative zone
Region of the epiphyseal plate that makes new chondrocytes to replace those that die at the diaphyseal end of the plate and contributes to longitudinal growth of the epiphyseal plate.
- pronated position
Forearm position in which the palm faces backward.
- pronation
Forearm motion that moves the palm of the hand from the palm forward to the palm backward position.
- prone
Face down position.
- proprioception
Sense of position and movement of the body.
- proprioceptor
Receptor cell that senses changes in the position and kinesthetic aspects of the body.
- proprioceptors.
Receptor cell that senses changes in the position and kinesthetic aspects of the body.
- protein
Class of organic compounds that are composed of many amino acids linked together by peptide bonds.
- proton
A heavy subatomic particle having a positive charge and found in the atom’s nucleus.
- protraction
Anterior motion of the scapula or mandible.
- proximal
Describes a position in a limb that is nearer to the point of attachment or the trunk of the body.
- pseudostratified columnar epithelium
Tissue that consists of a single layer of irregularly shaped and sized cells that give the appearance of multiple layers; found in ducts of certain glands and the upper respiratory tract.
- psoas major
Muscle that, along with the iliacus, makes up the iliopsoas.
- pubic symphysis
Joint formed by the articulation between the pubic bodies of the right and left hip bones.
- pubis
Anterior portion of the hip bone.
- pupil
Open hole at the center of the iris that light passes through into the eye.
- pyruvic acid
Series of metabolic reactions that breaks down glucose into pyruvate and produces ATP.
- quadriceps
Four muscles, that extend and stabilize the knee.
- quadriceps femoris
Muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip.
- quadriceps tendon
(Also, patellar tendon) tendon common to all four quadriceps muscles, inserts into the patella.
- radiocarpal joint
Wrist joint, located between the forearm and hand regions of the upper limb; articulation formed proximally by the distal end of the radius and the fibrocartilaginous pad that unites the distal radius and ulna bone, and distally by the scaphoid, lunate, and triquetrum carpal bones.
- radius
Bone located on the lateral side of the forearm.
- receptor
Protein molecule that contains a binding site for another specific molecule (called a ligand).
- receptor cell
Cell that transduces environmental stimuli into neural signals.
- receptor-mediated endocytosis
endocytosis of ligands attached to membrane-bound receptors
- rectus
Straight
- rectus abdominis
Long, linear muscle that extends along the middle of the trunk.
- rectus femoris
Quadricep muscle on the anterior aspect of the thigh.
- red marrow
Connective tissue in the interior cavity of a bone where hematopoiesis takes place.
- reflex arc
Circuit of a reflex that involves a sensory input and motor output, or an afferent branch and an efferent branch, and an integrating center to connect the two branches.
- refraction
The bending of light as it passes between mediums of different densities.
- refractory period
Time after the initiation of an action potential when another action potential cannot be generated.
- repolarization
Return of the membrane potential to its normally negative voltage at the end of the action potential.
- reserve zone
Region of the epiphyseal plate that anchors the plate to the osseous tissue of the epiphysis.
- resistance
(Also, load) The force opposing the action of a lever; in body systems, the resistance may be the mass of the limb (force of gravity acting on the bone) or a load being lifted or moved.
- resistance arm
Distance measured from the fulcrum to the resistance (centre of gravity or load being moved).
- resting membrane potential
The difference in voltage measured across a cell membrane under steady-state conditions, typically -70 mV.
- reticular
Fine fibrous protein, made of collagen subunits, which cross-link to form supporting “nets” within connective tissue.
- reticular formation
Diffuse region of gray matter throughout the brain stem that regulates sleep, wakefulness, and states of consciousness.
- reticular lamina
Matrix containing collagen and elastin secreted by connective tissue; a component of the basement membrane.
- retina
Nervous tissue of the eye at which phototransduction takes place.
- retinal
Cofactor in an opsin molecule that undergoes a biochemical change when struck by a photon (pronounced with a stress on the last syllable).
- retraction
Posterior motion of the scapula or mandible.
- rhodopsin
Photopigment molecule found in the rod photoreceptors.
- ribonucleic acid (RNA)
Ribose-containing nucleic acid that helps manifest the genetic code as protein.
- ribosome
Cellular organelle that functions in protein synthesis.
- rigor mortis
Stiffening of muscles that occurs after death.
- rod
One of the two types of receptor cells in the retina that is specialized for low-light vision
- rotation
Movement of a bone around a central axis (atlantoaxial joint) or around its long axis (proximal radioulnar joint; shoulder or hip joint); twisting of the vertebral column resulting from the summation of small motions between adjacent vertebrae.
- round window
Membrane that marks the end of the scala tympani.
- Ruffini corpuscle
See bulbous corpuscle
- saccule
Structure of the inner ear responsible for transducing linear acceleration in the vertical plane.
- sacral
Region of the sacrum, bone forming the back part of the pelvic cavity.
- sacrococcygeal curve
Anteriorly concave curvature formed by the sacrum and coccyx; a primary curve of the vertebral column.
- sacroiliac joint
Joint formed by the articulation between the auricular surfaces of the sacrum and ilium.
- sacrum
Single bone located near the inferior end of the adult vertebral column that is formed by the fusion of five sacral vertebrae; forms the posterior portion of the pelvis.
- saddle joint
Synovial joint in which the articulating ends of both bones are convex and concave in shape, such as at the first carpometacarpal joint at the base of the thumb; functionally classified as a biaxial joint.
- sagittal plane
Two-dimensional, vertical plane that divides the body or organ into right and left sides.
- saltatory conduction
Quick propagation of the action potential along a myelinated axon owing to voltage-gated Na+ channels being present only at the nodes of Ranvier.
- sarcolemma
Plasma membrane of a skeletal muscle fibre.
- sarcomere
longitudinally, repeating functional unit of skeletal muscle, with all of the contractile and associated proteins involved in contraction
- sarcopenia
Age-related muscle atrophy.
- sarcoplasm
Cytoplasm of a muscle cell.
- sarcoplasmic reticulum (SR)
Specialized smooth endoplasmic reticulum, which stores, releases, and retrieves Ca++.
- sartorius
Band-like muscle that flexes, abducts, and laterally rotates the leg at the hip.
- scala media
See cochlear duct
- scala tympani
Portion of the cochlea that extends from the apex to the round window.
- scala vestibuli
Portion of the cochlea that extends from the oval window to the apex.
- scapula
Shoulder blade bone located on the posterior side of the shoulder.
- Schwann cell
Glial cell type in the PNS that provides the myelin insulation for axons in nerves.
- sclera
White of the eye.
- sebaceous gland
Type of oil gland found in the dermis all over the body and helps to lubricate and waterproof the skin and hair by secreting sebum.
- second-class lever
A lever system in which the resistance is between the effort and the fulcrum; as the effort arm is always longer than the resistance arm, these are always power levers.
- secondary active transport
Active transport using pumps (carrier proteins) that are powered by the potential energy of a concentration gradient (usually of H+ or Na+).
- secondary ossification centre
Region of bone development in the epiphyses.
- selective permeability
Feature of any barrier that allows certain substances to cross but excludes others.
- semicircular canals
Structures within the inner ear responsible for transducing rotational movement information.
- semicircular ducts
Part of the membranous labyrinth contained in the semicircular canals.
- semimembranosus
The medial of the three muscles that comprise the hamstrings group.
- semitendinosus
The medial of the three muscles comprising the hamstring group.
- sensory modality
A particular system for interpreting and perceiving environmental stimuli by the nervous system.
- serosa
See serous membrane
- serous membrane
Membrane that covers organs and reduces friction; also referred to as serosa.
- sesamoid
A bone embedded in tendon; the only major sesamoid bone is the patella.
- set point
(In physiology) ideal value for a physiological parameter; the level or small range within which a physiological parameter such as blood pressure is stable and optimally healthful, that is, within its parameters of homeostasis.
- simple columnar epithelium
Tissue that consists of a single layer of column-like cells; promotes secretion and absorption in tissues and organs.
- simple cuboidal epithelium
Tissue that consists of a single layer of cube-shaped cells; promotes secretion and absorption in ducts and tubules.
- simple squamous epithelium
Tissue that consists of a single layer of flat scale-like cells; promotes diffusion and filtration across surface.
- skeletal muscle
Usually attached to bone, under voluntary control, each cell is a fiber that is multinucleated and striated.
- smooth muscle
Under involuntary control, moves internal organs, cells contain a single nucleus, are spindle-shaped, and do not appear striated; each cell is a fibre
- SO fibres
"Slow oxidative" muscle fibres that produce slower contractions, and primarily use aerobic respiration.
- soleus
Wide, flat muscle deep to the gastrocnemius.
- solute
Component of a solution, the substance dissolved in a solvent.
- solution
In chemistry, a homogeneous liquid mixture in which a solute is dissolved into molecules within a solvent.
- solvent
Component of a solution, the substance that dissolves the solute.
- soma
In neurons, that portion of the cell that contains the nucleus; the cell body, as opposed to the cell processes (axons and dendrites).
- somatic cell
A body cell, excluding germ cells. Normally diploid, each cell containing a complete set of genes.
- somatic nervous system
Functional division of the nervous system that is concerned with conscious perception, voluntary movement, and skeletal muscle reflexes.
- somatosensation
Sense of touch.
- somatotropin
See growth hormone (GH)
- special sense
Any sensory system associated with a specific organ structure, namely smell, taste, sight, hearing, and balance.
- speed lever
A lever system that can move a load/resistance with more effort and greater speed (compared to moving the resistance without a lever system); by definition, the mechanical advantage is less than one (effort arm < resistance arm).
- sphenoid bone
Unpaired bone that forms the central base of skull.
- sphincter
A ring-shaped smooth muscle that can open or close a passage in the body.
- spinal cavity
Division of the dorsal cavity that houses the spinal cord; also referred to as vertebral cavity.
- spinous process
Unpaired bony process that extends posteriorly from the vertebral arch of a vertebra.
- spiral ganglion
Location of neuronal cell bodies that transmit auditory information along the eighth cranial nerve.
- splanchnic nerves
Paired nerves that carry both autonomic and sensory fibres to the internal organs.
- spongy bone
(Also, cancellous bone) trabeculated osseous tissue that supports shifts in weight distribution.
- stapes
Ossicle of the middle ear (popularly called the stirrup) that is attached to the inner ear.
- static equilibrium
Modality of balance relating to position of the head with respect to gravity ("which way is up" and linear acceleration.
- stem cell
Cell that is oligo-, multi-, or pleuripotent that has the ability to produce additional stem cells rather than becoming further specialized.
- stereocilia
Array of apical membrane extensions in a hair cell that transduce movements when they are bent.
- sternocleidomastoid
Major muscle that laterally flexes and rotates the head.
- sternum
Flattened bone located at the center of the anterior chest.
- steroid
(Also, sterol) lipid compound composed of four hydrocarbon rings bonded to a variety of other atoms and molecules; not to be confused with anabolic steroids, a synthetic supplement
- sterol
See steroid
- stratified columnar epithelium
Tissue that consists of two or more layers of column-like cells, contains glands and is found in some ducts.
- stratified cuboidal epithelium
Tissue that consists of two or more layers of cube-shaped cells, found in some ducts.
- stratified squamous epithelium
Tissue that consists of multiple layers of cells with the most apical being flat scale-like cells; protects surfaces from abrasion.
- stratum basale
Deepest layer of the epidermis, made of epidermal stem cells.
- stratum corneum
Most superficial layer of the epidermis.
- stratum granulosum
Layer of the epidermis superficial to the stratum spinosum.
- stratum lucidum
Layer of the epidermis between the stratum granulosum and stratum corneum, found only in thick skin covering the palms, soles of the feet, and digits.
- stratum spinosum
Layer of the epidermis superficial to the stratum basale, characterized by the presence of desmosomes.
- stressor
(in physiology) Any stimulus that causes an imbalance in the internal environment.
- striation
Alignment of parallel actin and myosin filaments which form a banded pattern.
- subarachnoid space
Space between the arachnoid mater and pia mater that contains CSF and the fibrous connections of the arachnoid trabeculae.
- subscapularis
Muscle that originates on the anterior scapula and medially rotates the arm.
- subthalamus
Nucleus within the basal nuclei that is part of the indirect pathway.
- sudoriferous gland
Sweat gland.
- sulcus
Groove formed by convolutions in the surface of the cerebral cortex.
- superficial
Describes a position closer to the surface of the body.
- superior
Describes a position above or higher than another part of the body proper; also referred to as cranial.
- superior articular process
Bony process that extends upward from the vertebral arch of a vertebra that articulates with the inferior articular process of the next higher vertebra.
- superior colliculus
Half of the midbrain tectum that is responsible for aligning visual, auditory, and somatosensory spatial perceptions.
- supinated position
- supination
Forearm motion that moves the palm of the hand from the palm backward to the palm forward position.
- supine
Face up.
- supraspinatus
Muscle that abducts the arm.
- suspensory ligament
(Also zonule fibre) fibrous connections between the ciliary body and the lens.
- suture
Fibrous joint that connects the bones of the skull (except the mandible); an immobile joint (synarthrosis).
- sympathetic chain ganglia
Series of ganglia adjacent to the vertebral column that receive input from central sympathetic neurons.
- sympathetic division
Branch of the autonomic nervous system associated with emergency systems ("fight of flight").
- symphysis
Type of cartilaginous joint where the bones are joined by fibrocartilage.
- synapse
Narrow junction across which a chemical signal passes from neuron to the next, initiating a new electrical signal in the target cell.
- synaptic cleft
Small gap between cells in a chemical synapse where neurotransmitter diffuses from the presynaptic element to the postsynaptic element.
- synaptic end bulb
Swelling at the end of an axon where neurotransmitter molecules are released onto a target cell across a synapse.
- synarthrosis
Immobile or nearly immobile joint.
- synchondrosis
Type of cartilaginous joint where the bones are joined by hyaline cartilage.
- syncytium
A multinucleate cell formed by the fusion of multiple cells or the division of nuclei.
- syndesmosis
Type of fibrous joint in which two separated, parallel bones are connected by an interosseous membrane.
- synergist
Muscle whose contraction helps a prime mover in an action.
- synovial fluid
Thick, lubricating fluid that fills the interior of a synovial joint.
- synovial joint
Joint at which the articulating surfaces of the bones are located within a joint cavity formed by an articular capsule.
- synovial membrane
Thin layer that lines the inner surface of the joint cavity at a synovial joint; produces the synovial fluid.
- tactile corpuscle
(Also, Meissner corpuscle) receptor in the skin that responds to light touch.
- talus
Tarsal bone that articulates superiorly with the tibia and fibula at the ankle joint; also articulates inferiorly with the calcaneus bone and anteriorly with the navicular bone.
- tarsal
One of the seven bones that make up the posterior foot; includes the calcaneus, talus, navicular, cuboid, medial cuneiform, intermediate cuneiform, and lateral cuneiform bones.
- taste bud
Structures within a papilla on the tongue that contain gustatory receptor cells.
- tectorial membrane
Component of the organ of Corti that lays over the hair cells, into which the stereocilia are embedded.
- temporal bone
Paired bones that form the lateral, inferior portions of the skull, with squamous, mastoid, and petrous portions.
- tendon
Dense regular connective tissue that attaches skeletal muscle to bone.
- teres major
Muscle that extends the arm and assists in adduction and medial rotation of it.
- teres minor
Muscle that laterally rotates and extends the arm.
- thalamus
Major region of the diencephalon that is responsible for relaying information between the cerebrum and the hindbrain, spinal cord, and periphery.
- thermoreceptor
Sensory receptor specialized for temperature stimuli.
- third ventricle
Portion of the ventricular system that is in the region of the diencephalon.
- third-class lever
A lever system in which the effort is between the resistance and the fulcrum; the most common lever type in the bottom, these are always speed levers as the effort arm is always shorter than the resistance arm.
- thoracic
Mid-back, where ribs attach to vertebrae.
- thoracic cage
Consists of 12 pairs of ribs and sternum.
- thoracic cavity
Division of the anterior (ventral) cavity that houses the heart, lungs, esophagus, and trachea.
- thoracic curve
Anteriorly concave curvature of the thoracic vertebral column region; a primary curve of the vertebral column.
- thoracic duct
Major lymph vessel draining lymph into the circulatory system (blood) at the left subclavian vein.
- thoracic vertebrae
Twelve vertebrae numbered as T1–T12 that are located in the thoracic region (upper back) of the vertebral column.
- thoracolumbar system
Alternate name for the sympathetic division of the autonomic nervous system that is based on the anatomical location of central neurons in the lateral horn of the thoracic and upper lumbar spinal cord.
- tibia
Shin bone; the large, weight-bearing bone located on the medial side of the leg.
- tibialis anterior
Muscle located on the lateral surface of the tibia.
- tissue
Group of many similar cells (though sometimes composed of a few related types) that work together to perform a specific function.
- trabeculae
(Singular= trabecula) spikes or sections of the lattice-like matrix in spongy bone.
- trachea
Tube composed of cartilaginous rings and supporting tissue that connects the lung bronchi and the larynx; provides a route for air to enter and exit the lung.
- tract
Cord-like bundle of axons located in the peripheral nervous system that transmits sensory input and response output to and from the central nervous system.
- transduction
Process of changing an environmental stimulus into the electrochemical signals of the nervous system.
- transverse foramen
Paired bony processes that extends laterally from the vertebral arch of a vertebra.
- transverse plane
Two-dimensional, horizontal plane that divides the body or organ into superior and inferior portions.
- transverse process
Paired bony processes that extends laterally from the vertebral arch of a vertebra.
- transverse tubules
Projection of the sarcolemma into the interior of the cell.
- transversus abdominis
Deep layer of the abdomen that has fascicles arranged transversely around the abdomen.
- trapezius
Muscle that stabilizes the upper part of the back.
- triceps brachii
Three-headed muscle that extends the forearm.
- trochlear nerve
Fourth cranial nerve; responsible for contraction of one of the extraocular muscles.
- tropomyosin
Regulatory protein that covers myosin-binding sites to prevent actin from binding to myosin.
- troponin
Regulatory protein that binds to actin, tropomyosin, and calcium.
- true ribs
Vertebrosternal ribs 1–7 that attach via their costal cartilage directly to the sternum.
- tympanic membrane
Ear drum.
- ulna
Bone located on the medial side of the forearm.
- umbilical region
central abdominopelvic region including the belly button.
- uniaxial joint
Type of diarthrosis; joint that allows for motion within only one plane (one axis).
- uterine tube
(Also, fallopian tube or oviduct) duct that facilitates transport of an ovulated oocyte to the uterus.
- utricle
Structure of the inner ear responsible for transducing linear acceleration in the horizontal plane.
- vagus nerve
Tenth cranial nerve; responsible for the autonomic control of organs in the thoracic and upper abdominal cavities.
- valence shell
Outermost electron shell of an atom.
- vascular
Relating to circulation of blood.
- vascular tunic
Middle layer of the eye primarily composed of connective tissue with a rich blood supply.
- vasodilation
Opening up, or increasing interior (lumen) diameter of a blood vessel.
- ventral
See anterior
- ventral cavity
Larger body cavity located anterior to the posterior (dorsal) body cavity; includes the serous membrane-lined pleural cavities for the lungs, pericardial cavity for the heart, and peritoneal cavity for the abdominal and pelvic organs; also referred to as anterior body cavity.
- ventricle
Remnants of the hollow center of the neural tube that are spaces for cerebrospinal fluid to circulate through the brain.
- vertebra
Individual bone in the neck and back regions of the vertebral column.
- vertebral (spinal) canal
Bony passageway within the vertebral column for the spinal cord that is formed by the series of individual vertebral foramina.
- vertebral arch
Bony arch formed by the posterior portion of each vertebra that surrounds and protects the spinal cord.
- vertebral cavity
See spinal cavity
- vertebral column
Entire sequence of bones that extend from the skull to the tailbone.
- vertebral foramen
Opening associated with each vertebra defined by the vertebral arch that provides passage for the spinal cord.
- vesicle
Membrane-bound structure that contains materials within or outside of the cell.
- vestibular ganglion
Location of neuronal cell bodies that transmit equilibrium information along the eighth cranial nerve.
- vestibular membrane
Membrane separating the cochlear duct from the scala vestibuli.
- vestibule
In the ear, the portion of the inner ear responsible for the sense of equilibrium.
- vestibulocochlear nerve
Eighth cranial nerve; responsible for the sensations of hearing and balance.
- visceral
Facing the organs (opposite of parietal).
- viscous
Thick consistency between solid and liquid.
- visual acuity
Property of vision related to the sharpness of focus, which varies in relation to retinal position.
- vitamin
Organic compound required by the body to perform biochemical reactions like metabolism and bone, cell, and tissue growth.
- vitreous humour
Viscous fluid that fills the posterior chamber of the eye.
- Volkmann's canal
See perforating canal
- voltage-gated channel
Ion channel that opens because of a change in the charge distributed across the membrane where it is located.
- voluntary
(In physiology) under conscious control of the brain.
- white matter
Regions of the nervous system containing mostly myelinated axons, making the tissue appear white because of the high lipid content of myelin.
- xiphoid process
Small process that forms the inferior tip of the sternum.
- yellow marrow
Connective tissue in the interior cavity of a bone where fat is stored.
- Z-disc
(Also Z-line) structure at the end of sarcomeres to which actin is anchored.
- Z-line
See Z-disc
- zone of calcified matrix
Region of the epiphyseal plate closest to the diaphyseal end; functions to connect the epiphyseal plate to the diaphysis.
- zone of maturation and hypertrophy
Region of the epiphyseal plate where chondrocytes from the proliferative zone grow and mature and contribute to the longitudinal growth of the epiphyseal plate.
- zonule fibre
See suspensory ligament