Chapter 19 - The cardiovascular system: Blood vessels (part a). When you finish this chapter, you should: Describe the three layers that typically form the wall of a blood vessel, and state the function of each; define vasoconstriction and vasodilation; compare and contrast the structure and function of the three types of arteries;. | 19 The Cardiovascular System: Blood Vessels: Part A Blood Vessels Delivery system of dynamic structures that begins and ends at the heart Arteries: carry blood away from the heart; oxygenated except for pulmonary circulation and umbilical vessels of a fetus Capillaries: contact tissue cells and directly serve cellular needs Veins: carry blood toward the heart Figure Large veins (capacitance vessels) Large lymphatic vessels Arteriovenous anastomosis Lymphatic capillary Postcapillary venule Sinusoid Metarteriole Terminal arteriole Arterioles (resistance vessels) Muscular arteries (distributing vessels) Elastic arteries (conducting vessels) Small veins (capacitance vessels) Lymph node Capillaries (exchange vessels) Precapillary sphincter Thoroughfare channel Lymphatic system Venous system Arterial system Heart Structure of Blood Vessel Walls Arteries and veins Tunica intima, tunica media, and tunica externa Lumen Central blood-containing space Capillaries Endothelium with sparse basal lamina Figure Tunica media (smooth muscle and elastic fibers) Tunica externa (collagen fibers) Lumen Artery Lumen Vein Internal elastic lamina External elastic lamina Valve (b) Endothelial cells Basement membrane Capillary network Capillary Tunica intima • Endothelium • Subendothelial layer Tunics Tunica intima Endothelium lines the lumen of all vessels In vessels larger than 1 mm, a subendothelial connective tissue basement membrane is present Tunics Tunica media Smooth muscle and sheets of elastin Sympathetic vasomotor nerve fibers control vasoconstriction and vasodilation of vessels Tunics Tunica externa (tunica adventitia) Collagen fibers protect and reinforce Larger vessels contain vasa vasorum to nourish the external layer Table (1 of 2) Table (2 of 2) Elastic (Conducting) Arteries Large thick-walled arteries with elastin in all three tunics Aorta and its major branches Large lumen offers low-resistance Act as pressure reservoirs—expand and recoil as blood is . | 19 The Cardiovascular System: Blood Vessels: Part A Blood Vessels Delivery system of dynamic structures that begins and ends at the heart Arteries: carry blood away from the heart; oxygenated except for pulmonary circulation and umbilical vessels of a fetus Capillaries: contact tissue cells and directly serve cellular needs Veins: carry blood toward the heart Figure Large veins (capacitance vessels) Large lymphatic vessels Arteriovenous anastomosis Lymphatic capillary Postcapillary venule Sinusoid Metarteriole Terminal arteriole Arterioles (resistance vessels) Muscular arteries (distributing vessels) Elastic arteries (conducting vessels) Small veins (capacitance vessels) Lymph node Capillaries (exchange vessels) Precapillary sphincter Thoroughfare channel Lymphatic system Venous system Arterial system Heart Structure of Blood Vessel Walls Arteries and veins Tunica intima, tunica media, and tunica externa Lumen Central blood-containing space Capillaries Endothelium with sparse .
