10/1/2010 Objectives Overview of the vessels. Human Anatomy & Define the different type of blood vessels. Physiology BI 233 --ArteriesArteries --VeinsVeins Course Intro --CapillariesCapillaries Identify the tissue layers of blood vessels. Distinguish the different forms of arteries, veins and capillaries. Homework Preparations Function of the Blood Vessels Cardiac Flow in HW section (diagram) Transport blood to and from the heart. Need colored pencils or marker Due Wed I. Arteries deliver oxygenated blood to tissues. HW #1 Artery Labeling II Veins carry deoxygenated blood to the Due in lab (Thursday) heart. III Capillaries are the site of gas exchange for internal respiration. Venous system Arterial system Tunica intima Large veins Heart (capacitance • Endothelium Valve • Subendothelial layer vessels) Elastic arteries Large (conducting Internal elastic lamina lymphatic vessels) Tunica media vessels (smooth muscle and Lymph elastic fibers) node Muscular arteries (distributing External elastic lamina Lymphatic system vessels) Tunica externa Small veins (collagen fibers) Arteriovenous (capacitance anastomosis vessels) Lymphatic Sinusoid capillary Lumen Arterioles Lumen Capillary Vein (resistance vessels) Artery network Postcapillary Terminal arteriole Basement membrane venule Metarteriole Endothelial cells Thoroughfare Capillaries Precapillary sphincter channel (exchange vessels) (b) Capillary Copyright © 2010 Pearson Education, Inc. Copyright © 2010 Pearson Education, Inc. 1 10/1/2010 Tissue Layers of Vessels Tissue Layers of Vessels Tunica interna Tunica media Inner most layer (lining of lumen) Middle layer of blood vessels Endothelium Consists of smooth muscle Simple squamous cells Sheets of elastin (protein layer) for Selectively permeable variable constriction. Found in ALL vessel types Contain collagen ––givesgives strength Thickest in muscular arteries. circulation. Tissue Layers of Vessels Relative cross- sectional area of different vessels Tunica externa of the vascular bed Outermost layer Total area Composed of loose connective tissue (cm2) of the vascular Collagen reinforced bed Protection of vessel In large vessels contains tiny blood Velocity of vessels –– vas vasorum blood flow (cm/s) Aka Tunica adventitia Different forms of Arteries Capillaries I. Elastic Arteries Site of material exchange with the Nearest heart interstitial fluids. II. Muscular Arteries --BloodBlood gasses Deliver blood to specific organs --NutrientsNutrients III. Resistance arteries Associated terminology aka Arterioles (small) Capillary bed ––tortuoustortuous pathway. Regulate blood flow to capillaries. Precapillary sphincter ––circularcircular muscle Metarteriole ––vesselvessel running though capillary bed. that controls flow through bed. Main pathway for blood. 2 10/1/2010 Vascular shunt Precapillary Different forms of Capillaries sphincters Metarteriole Thoroughfare channel I. Continuous Abundant in skin & muscles True capillaries Terminal arteriole Postcapillary venule II.II. Fenestrated (a) Sphincters open —blood flows through true capillaries. Predominant in kidney & small intestine, very permeable. III. Sinusoidal Common in liver, bone marrow, Terminal arteriole Postcapillary venule lymphoid issue. (b) Sphincters closed —blood flows through metarteriole thoroughfare channel and bypasses true capillaries. Copyright © 2010 Pearson Education, Inc. Veins & Venules Vascular Anastomoses -- Carry deoxygenated blood back to the heart. A network of blood vessels that supply a region -- Said to join, merge & converge. of the body. -- 65% of the body’s blood supply in venous Occurs in & around: system. -- Joints -- Contain valves to prevent backflow. -- Abdominal organs Post capillary venules: -- Brain Porous -- Heart White blood cells & fluids easily move out Importance: Alternate pathways if traffic gets jammed or blocked. Preparation for next class Preparation for Lab Read Sections on Blood Vessels Prelab ––LookLook over conditions on page 741. Preview On lab day bring: Part II ––throughthrough Hypertension pg 706 -- Textbook 712 Lab Book Study Guide notes BI233 Recommended (cardiovascular section) Answer 6363--7070 in handouts on pg 1 &2 CP. Blood Pressure Cuff (if you have your own) 3.