4 November 2011 Properties of Blood Vessels Announcements & Reminders Test 2 on Monday Updates posted to Website Chapter questions posted to Website Photo-shoot Friday 1 pm Biology Suite

1QQ # 25 for 8:30 By what means can a person with a heart transplant increase their cardiac output while jogging? What are the effects of sympathetic stimulation on heart rate and stroke volume?

1QQ # 25 for 9:30 By what means is stroke volume decreased in a person who has just finished jogging and is now standing still and is no longer breathing as deeply as while jogging? What are the effects of parasympathetic stimulation on heart rate and stroke volume?

Properties of Blood Vessels All vessels and heart chambers lined with ENDOTHELIAL cells (simple squamous) Arteries Arterioles Capillaries Venules Veins Elastic, low compliance, large diameter, low resistance vessels Variable Resistance vessels Exchange Wall = simple squamous endothelium No smooth muscle; cannot change diameter Capacitance vessels, high compliance, low pressure, valves for unidirectional flow

Fig. 12.29 S 2 Aorta Brachial or Femoral artery Damage to artery vs vein Pusatile flow 12.29.jpg

S 3 Fig. 12.39b Analogy: river width and flow 12.39b.jpg

Fig. 12.30 S 4 Stretching elastic connective tissue Elastic recoil of stretched arterial walls during ventricular systole maintains arterial pressure during diastole as blood drains into arterioles. Atherosclerosis Recoil of elastic connective tissue 12.30.jpg Point of Confusion: Smooth muscles in arterial walls DO NOT rhythmically contract, do not pump!

Arteries and Arterial Pressure Mean Arterial Pressure Arteriole Arterioles have two main functions: 1) regulate flow to tissues and organs and 2) responsible for Total Peripheral Resistance which influences Blood Pressure. MAP = CO x TPR Poiseulle’s Equation

Mean Arterial Pressure Fig. 12.50 Cardiac Output Heart Arteries Mean Arterial Pressure Arterioles Totol Peripheral Resistance 12.50.jpg Kidneys CNS Gut Sk. Muscle Skin

S 7 Receptors for other ligands Alpha receptors more common except in skeletal muscle arterioles which have more B2 receptors

Fig. 12.36 S 8 No parasympathetic innervation of arterioles! Metabolic vasodilators No parasympathetic innervation of arterioles! Importance of sympathetic “tone.” 12.36.jpg Metabolic autoregulation, flow autoregulation, myogenic autoregulation