Anatomy and Physiology Essay

The primary goal of this lab is to learn the names of many blood vessels. You will use the models provided as well as pictures in your lab book. Microscopic Structure of Blood Vessels Tunica intima: lines the lumen of the blood vessel. Continuous with endocardium of heart. Is extremely smooth to decrease resistance to blood flow. (Made of epithelium) Tunica media: More bulky middle coat. Composed of smooth muscle and elastin. Regulation in the diameter of blood vessels, which alters peripheral resistance and blood pressure. Tunica externa (adventitia): Outermost tunic. Function is primarily supportive and protective (areolar and fibrous CT) Picture Generalized Structure of Arteries, Veins and Capillaries Types of Blood Vessels Elastic arteries: Contain much elastic tissue Larger arteries closer to the heart Must expand when heart pumps much blood into them and then passively recoil after blood passes by. Thus, must withstand pressure fluctuations Muscular arteries: Have less elastic tissue, but substantial muscle tissue Smaller arteries farther from heart Exposed to less extreme pressure fluctuations Veins: Far from heart Not subjected to pressure fluctuations Are low pressure vessels thus are thin walled Blood flows against gravity so 1. Have larger lumens 2. Have valves to prevent backflow 3. Skeletal muscle pump Capillaries: Tiniest vessels One cell layer thick: endothelium with underlying basal lamina (tunica intima) Thinnest for making exchanges between blood and tissue cells Activity One Observing a vein and an artery on a microscope slide. Major Systemic Arteries of the Body Activity Two Use the models provided to find arteries listed Use pictures on the following pages to assist Both models and pictures will be used on the test Major Systemic Veins of the Body Activity Three Use the models provided to find veins listed Use pictures on the following pages to assist Both models and pictures will be used on the test Special Circulations Pulmonary Circulation Does not serve metabolic needs of body tissues Function is to bring blood close to alveoli in order do gas exchange Pulmonary arteries are structurally similar to veins Create a low pressure bed in the lungs Carry deoxygenated blood from heart to lungs Pulmonary veins