Blood Vessels Chapter 21

Functions of Blood Vessels Carry blood away from the heart - arteries Transport blood to tissues - capillaries Return blood to the heart – veins

Walls of Blood Vessels 3 layers Inner layer is endothelium = tunica intima Middle layer = tunica media Outer layer = tunica externa Vasa vasorum are the vessels that supply the larger blood vessels

Atherosclerosis

Arteries Elastic arteries are the large arteries Muscular arteries are the smaller arteries Arterioles are very small, <0.5mm in diameter Capable of vasoconstriction and vasodilation

Systemic Arterial System FG22_10.JPG Title: An Overview of the Systemic Arterial System Notes: Figure 22-10 is an overview of the arterial system. This figure indicates the relative locations of major systemic arteries. Keywords: arterial system, systemic, carotid, aorta, subclavian, axillary, renal, mesenteric, iliac, femoral, genicular, popliteal, brachial, celiac, brachiocephalic, vertebral, palmar, plantar

Major Arteries of the Trunk FG22_16.JPG Title: Major Arteries of the Trunk Notes: Diagrammatic view of the major arteries of the trunk. Keywords: arteries, trunk, abdominal aorta, gonadal, mesenteric, splenic, gastric, celiac, phrenic, hepatic, suprarenal, renal, lumbar, iliac, thoracic aorta, pericardials, esophageals, bronchials, mediastinals, intercostals, subclavian, vertebral thyrocervical

Arteries of the Chest and Upper Extremity FG22_12A.JPG Title: Arteries of the Chest and Upper Extremity Notes: (a) Arteries originating along the aortic arch shown branching into the chest and upper arm. (b)Anterior view of forearm. (c)Anterior view of axillary region. (d)Flow chart showing arterial distribution from the aortic arch. Keywords: arteries, chest, upper extremity, aortic arch, carotid, brachiocephalic, ascending, descending, thoracic, abdominal, ulnar, brachial, subscapular, brachial, humeral, thyrocervical, vertebral, suprascapular, axillary, intercostals, radial, palmar

Capillaries All blood-tissue exchange occurs here Tissue = tunica intima Three types Continuous Fenestrated Sinusoids

Capillary Bed with Precapillary Sphincters

Veins Venules Medium-sized veins Large veins Very small Contain only tunica intima and tunica externa Medium-sized veins Large veins contain the same 3 layers as arteries Tunica media is much thinner Tuna externa is the thickest layer

Veins with Valves Some veins contain valves – prevent blood from flowing backwards

Varicose Veins www.sirweb.org/patPub/varicoseVeinMain.shtml www.veinhelp.com/varicoseVeins.htm

Systemic Venous System FG22_21.JPG Title: An Overview of the Systemic Venous System Notes: All of the systemic veins (except the cardiac veins) drain into either the superior vena cava or the inferior vena cava. The superior vena cava (SVC) receives blood from the tissues and organs of the head, neck, chest, shoulders, and upper extremities. Keywords: systemic venous system, overview, jugular, vertebral, subclavian, axillary, cephalic, brachial, basilic, hepatic, cubital, radial, antebrachial, ulnar, palmar, digital, saphenous, popliteal, peroneal, tibial, plantar, femoral, iliac, lumbar, gonadal

Venous System of the Trunk and Upper Limb FG22_23.JPG Title: The Venous Drainage of the Trunk and Upper Limb Notes: A diagrammatic view of the venous drainage of the trunk and upper limb. Keywords: venous drainage, upper extremities, chest, abdomen, vertebral, jugular, subclavian, brachiocephalic, vena cava, axillary, cephalic, hemiazygos, brachial, basilic, phrenics, suprarenals, radial, iliac, lumbars, gonadals, renals, hepatics, mediastinals