Measurable Outcomes

• Visually identify major components, vessels, and structures of a dissected heart.
• Determine the anatomical structures of the heart on available models.
• Determine the pathway of blood flow through the heart.
• List and accurately classify the distinct types of blood cells from histological slides.
• Recognize the features of cardiac tissue under a microscope.
• Identify the major blood vessels required for this lab.
• Distinguish between arterial and venous flow.

Background

The cardiovascular system is responsible for the circulation of blood and transport of nutrients.  Large multicellular organisms developed such a system as a means of actively transporting nutrients to the cells of the body. The heart is the organ of focus in this lab. It is divided into four distinct chambers, which in concert work to circulate blood. When the heart beats, it pumps blood into two different circuits: pulmonary and systemic. Pulmonary circulation carries blood from the right side of the heart to the alveoli of the lungs and back to the left side of the heart, while the systemic circulation carries blood from the left side of the heart to all the organs and tissues of the body, then back to the right side of the heart. If it were possible to stretch out all of the blood vessels in the body, they would measure 60,000 to 100,000 miles, enough circle the earth roughly four times. The heart is an incredible organ capable, on average, of circulating roughly 2,000 gallons worth of blood each day. Furthermore, the heart is one of the few organs capable of operating entirely apart from the central nervous system which makes it one of the hardest working organs.

Blood is classified as liquid connective tissue and is vital in its roles of transportation, regulation, and protection. It is made of distinct types of cells, mostly derived from bone marrow, and helps maintain homeostasis. Plasma and cellular elements are the two main components of blood, where plasma makes up 55% of blood and cellular elements make up 45%. Plasma is mostly water but contains proteins and other solutes as well. The vast majority of cell elements are erythrocytes with less than 1% comprising of leukocytes and platelets.

In this lab we will focus on the major blood vessels of the cardiovascular system. Arteries are blood vessels that always carry blood away from the heart; the blood they carry is oxygenated (exception: pulmonary arteries). They generally have thicker walls than veins, the other major blood vessels in the cardiovascular system. Veins carry blood toward the heart and carry deoxygenated blood (exception: pulmonary veins). Both vessel types are formed by the tunica intima, tunica media, and tunica adventitia.

Vocabulary for the Cardiovascular System can be found on page(s) 163-165 .