AH 2330 Lecture Notes - Lecture 11: Skeletal Muscle, Muscle Tone, Arteriole
Document Summary
Law of la place: tension is proportional to radius. More tension on walls of very large vessels. Aneurisms (cid:523)(cid:498)swelling of bv(cid:499)(cid:524) tend to occur in large vessels. Much higher proportion of muscle cells and no elastin in all 3 tunics. Extra layer of smooth muscle gives ability to vasocontrict or change radius to change lumen, or vasodilate. Most arteries are muscular: elastic arteries: largest of the arteries bc they contain elastin in all three tunics. Pulmonary + aorta arteries are elastic (igh compliance bc of elasticity measures how easy it is to stretch a vessel. distribute blood: lumen of arteries offer relatively little blood flow i. pressure reservoir: characteristic of elastic arteries: when left ventricle contracts, ejects a stroke volume only 1/3rd leaves through arteries pressure never goes to 0 like ventricular pressure does. Rest will continue to flow out of the arteries during diastole (relaxation)
