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Learn about the cardiovascular system's response to exercise, hemorrhaging, and blood circulation patterns. From light to heavy exercise, short-term and long-term responses to hemorrhaging, and an overview of the distribution of blood vessels. Explore the pulmonary and systemic circuits, arteries of the chest, limbs, head, neck, brain, and trunk. Understand special circulation in the brain, heart, and lungs. Figure illustrations included.
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Chapter 21, part 3 Blood Vessels and Circulation
Exercise and the Cardiovascular System • Light exercise results in • Extensive vasodilation • Increased venous return • A rise in cardiac output • Heavy exercise results in • Increased blood flow to skeletal muscles • Restriction of blood flow to nonessential organs
Cardiovascular response to hemorrhaging: short term • Carotid and aortic reflexes increase CO and peripheral vasoconstriction • Sympathetic nervous system elevates blood pressure • E and NE increase cardiac output and ADH enhances vasoconstriction
Cardiovascular response to hemorrhaging: long term • Decline in capillary blood pressure recalls fluids from interstitial spaces • Aldosterone and ADH promote fluid retention • Increased thirst promotes water absorption across the digestive tract • Erythropoietin ultimately increases blood volume and improves O2 delivery
Figure 21.18 Cardiovascular Responses to Hemorrhaging and Blood Loss Figure 21.18
Special circulation • The brain • Four arteries which anastomose insuring constant blood flow • The heart • Coronary arteries arising from the ascending aorta • The lungs • Pulmonary circuit, regulated by local responses to O2 levels • Opposite other tissues (declines in O2 cause vasodilation)
The distribution of blood: General functional patterns • Peripheral distribution of arteries and veins is generally symmetrical • Except near the heart • Single vessels may have several names as they cross anatomical boundaries • Arteries and corresponding veins usually travel together
Figure 21.20 An Overview of the Patterns of Circulation Figure 21.20
Pulmonary circuit consists of pulmonary vessels • Arteries which deliver blood to the lungs • Capillaries in the lungs where gas exchange occurs • Veins which deliver blood to the left atrium
Figure 21.21 The Pulmonary Circuit PLAY Animation: Cardiovascular System, Abdomen Figure 21.21
Systemic arteries • Ascending aorta • Right and left coronary arteries originate from base of aortic sinus • Aortic arch and branches • Brachiocephalic • Left common carotid • Left subclavian arteries • Descending aorta and its branches • Thoracic and abdominal aortas
Figure 21.22 An overview of the Major Systemic Arteries Figure 21.22
Figure 21.23 Arteries of the Chest and Upper Limb Figure 21.23a
Figure 21.23 Arteries of the Chest and Upper Limb Figure 21.23b
Figure 21.24 Arteries of the Head and Neck Figure 21.24
Figure 21.25 Arteries of the Brain Figure 21.25
Figure 21.26 Major Arteries of the Trunk Figure 21.26a
Figure 21.26 Major Arteries of the Trunk Figure 21.26b