BIOL 2021 Lecture Notes - Lecture 13: Cardiac Muscle, Teres Major Muscle, Cervical Vertebrae
24 Aug 2016
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Document Summary
Composed of three layers called tunics: tunica interna (intima) composed of simple squamous epithelium (endothelium), is in intimate contact with blood, tunica media sheets of smooth muscle, elastic connective tissue and collagen. Relaxation vasodilation: tunica externa composed of connective tissue. Lumen central, blood-filled space of a blood vessel. Types of arteries: elastic (conducting) arteries largest arteries, range in diameter from 1-2. 5cm. High elastin content dampens the surge of blood pressure: muscular (distributing) arteries lie distal to elastic arteries. Unique features include internal and external elastic laminae: arterioles smallest arteries, range in diameter from 10 m to 0. 3mm. Diameter is controlled by local factors in the tissue and the sympathetic nervous system. Capillaries: smallest blood vessels, renew and refresh surrounding tissue fluid, deliver oxygen and nutrients and remove carbon dioxide and wastes, diameter is very small, rbcs pass through in single file, site-specific functions of capillaries: Lungs oxygen enters blood, carbon dioxide leaves. Capillary beds: network of capillaries running through tissues.
