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Fig. 13.5 Copyright © McGraw-Hill Education. Permission required for reproduction or display. CO 2 O 2 Brain Circulation to brain and tissues of head Aorta Circulation to upper limbs CO2 Pulmonary arteries O2 Pulmonary trunk Pulmonary vein O2 CO2 Heart Pulmonary circulation Digestive tract circulation Liver circulation Kidney Renal circulation Circulation to lower limbs CO2 O2
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Fig. 13.1-2 Tunica adventitia Tunica media (elastic tissue
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Tunica adventitia Tunica media (elastic tissue and smooth muscle) Connective tissue Tunica intima Endothelium and basement membrane (a) Elastic arteries. The tunica media is mostly elastic connective tissue. Elastic arteries recoil when stretched, which prevents blood pressure from falling rapidly. Tunica adventitia Elastic connective tissue Tunica media Smooth muscle Elastic connective tissue Connective tissue Tunica intima Endothelium and basement membrane (b) Muscular arteries. The tunica media is a thick layer of smooth muscle. Muscular arteries regulate blood flow to different regions of the body.
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Atherosclerotic plaque
Fig Copyright © McGraw-Hill Education. Permission required for reproduction or display. Endothelium Vessel wall Atherosclerotic plaque
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Fig Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Tunica adventitia Tunica media (elastic tissue and smooth muscle) Connective tissue Tunica intima Endothelium and basement membrane (a) Elastic arteries. The tunica media is mostly elastic connective tissue. Elastic arteries recoil when stretched, which prevents blood pressure from falling rapidly. Tunica adventitia Elastic connective tissue Tunica media Smooth muscle Elastic connective tissue Connective tissue Tunica intima Endothelium and basement membrane (b) Muscular arteries. The tunica media is a thick layer of smooth muscle. Muscular arteries regulate blood flow to different regions of the body. Tunica adventitia Tunica media Tunica intima (c) Arterioles. All three tunics are present; the tunica media consists of only one or two layers of circular smooth muscle cells. Endothelium (d) Capillaries. Walls consist of only a simple endothelium surrounded by delicate loose connective tissue.
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Arteriole Precapillary sphincters Capillaries Capillary network Venule
Fig. 13.3 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Arteriole Precapillary sphincters Capillaries Capillary network Venule
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Fig. 13.1 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Tunica adventitia Tunica adventitia Tunica media (elastic tissue and smooth muscle) Tunica media Connective tissue Tunica intima Connective tissue Endothelium and basement membrane Tunica intima Endothelium and basement membrane (a) Elastic arteries. The tunica media is mostly elastic connective tissue. Elastic arteries recoil when stretched, which prevents blood pressure from falling rapidly. (g) Large veins. All three tunics are present. The tunica media is thin but can regulate vessel diameter because blood pressure in the venous system is low. The predominant layer is the tunica adventitia. Tunica adventitia Elastic connective tissue Tunica media Tunica adventitia Smooth muscle Elastic connective tissue Tunica media Connective tissue Tunica intima Connective tissue Endothelium and basement membrane Tunica intima Endothelium and basement membrane (b) Muscular arteries. The tunica media is a thick layer of smooth muscle. Muscular arteries regulate blood flow to different regions of the body. (f) Small and medium veins. All three tunics are present. Tunica adventitia Tunica intima Tunica media Tunica intima (c) Arterioles. All three tunics are present; the tunica media consists of only one or two layers of circular smooth muscle cells. (e) Venules. Only the tunica intima resting on a delicate layer of dense connective tissue is present. Endothelium (d) Capillaries. Walls consist of only a simple endothelium surrounded by delicate loose connective tissue.
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©Ed Reschke/Photolibrary/Getty Images
Fig. 13.2 Copyright © McGraw-Hill Education. Permission required for reproduction or display. V V A A LM 250x Tunica intima Tunica media Tunica adventitia ©Ed Reschke/Photolibrary/Getty Images
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Valve closed Vein Valve open Direction of blood flow Fig. 13.4
Copyright © McGraw-Hill Education. Permission required for reproduction or display. Valve closed Vein Valve open Direction of blood flow
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Fig. 13.21 1 When the cuff pressure is high
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1 When the cuff pressure is high enough to keep the brachial artery closed, no blood flows through it, and no sound is heard. Degree to which brachial artery is open during: 300 Systole Diastole 250 2 When cuff pressure decreases and is no longer able to keep the brachial artery closed, blood is pushed through the partially opened brachial artery, producing turbulent blood flow and a sound. Systolic pressure is the pressure at which a sound is first heard. No sound 1 Blocked 200 2 Sound is first heard. 150 Blocked or partially open Systolic pressure (120 mm Hg) Korotkoff sounds 100 3 Diastolic pressure (80 mm Hg) 3 As cuff pressure continues to decrease, the brachial artery opens even more during systole. At first, the artery is closed during diastole, but as cuff pressure continues to partially opens during diastole. Turbulent blood flow during systole produces Korotkoff sounds, although the pitch of the sounds changes as the artery becomes more open. Sound disappears. 50 4 Arm No sound Open 4 Eventually, cuff pressure decreases below the pressure in the brachial artery, and it remains open during systole and diastole. Nonturbulent flow is reestablished, and no sounds are heard. Diastolic pressure is the pressure at which the sound disappears. Pressure cuff Elbow
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Venules, veins, and venae cavae
Fig Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 140 120 Systolic pressure Mean blood pressure Pulse pressure 100 80 Pressure (mm Hg) Diastolic pressure 60 40 20 Aorta Venules, veins, and venae cavae Arteries Arterioles Capillaries
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Fig. 13.24 1 At the arterial end of the capillary, the movement of
Copyright © McGraw-Hill Education. Permission required for reproduction or display. 1 At the arterial end of the capillary, the movement of fluid out of the capillary due to blood pressure is greater than the movement of fluid into the capillary due to osmosis. One-tenth volume passes into lymphatic capillaries. 3 Nine-tenths volume returns to capillary. Net movement of fluid out of the capillary into the interstitial space Net movement of fluid into the capillary from the interstitial space Outward movement of fluid due to blood pressure Inward movement of fluid due to osmosis 2 At the venous end of the capillary, the movement of fluid into the capillary due to osmosis is greater than the movement of fluid out of the capillary due to blood pressure. Inward movement of fluid due to osmosis Outward movement of fluid due to blood pressure 1 2 3 Approximately nine-tenths of the fluid that leaves the capillary at its arterial end reenters the capillary at its venous end. About one-tenth of the fluid passes into the lymphatic capillaries. Blood flow Arterial end Venous end
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Arteriole Precapillary sphincters Capillaries Capillary network Venule
Fig. 13.3 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Arteriole Precapillary sphincters Capillaries Capillary network Venule
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Fig. 13.25 Blood flow increases Blood flow decreases 1 2
Copyright © McGraw-Hill Education. Permission required for reproduction or display. Blood flow increases Blood flow decreases 1 2 Smooth muscle of precapillary sphincter relaxes. Smooth muscle of precapillary sphincter contracts. Blood flow Blood flow 1 Relaxation of precapillary sphincters. Precapillary sphincters relax as the tissue concentration of O2 and nutrients, such as glucose, amino acids, and fatty acids, decreases. The precapillary sphincters also relax as CO2 concentration increases and pH decreases. 2 Contraction of precapillary sphincters. Precapillary sphincters contract as the tissue concentration of O2 and nutrients, such as glucose, amino acids, and fatty acids, increases. The precapillary sphincters also contract as the CO2 concentration decreases and pH increases.
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Vasomotor center in medulla oblongata Spinal cord Sympathetic
Fig Copyright © McGraw-Hill Education. Permission required for reproduction or display. Vasomotor center in medulla oblongata Spinal cord Sympathetic nerve fibers Blood vessels Sympathetic chain
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Fig. 13.27 Carotid sinus baroreceptors 1 Baroreceptors in the carotid
Copyright © McGraw-Hill Education. Permission required for reproduction or display. Carotid sinus baroreceptors 1 Baroreceptors in the carotid sinus and aortic arch monitor blood pressure. 1 Aortic arch baroreceptors 2 Sensory nerves conduct action potentials to the cardioregulatory and vasomotor centers in the medulla oblongata. Sensory nerve fiber 3 2 3 Increased parasympathetic stimulation of the heart decreases the heart rate. Vagus nerve (parasympathetic) 4 Increased sympathetic stimulation of the heart increases the heart rate and stroke volume. Cardioregulatory and vasomotor centers in the medulla oblongata 4 Sympathetic nerves 5 Increased sympathetic stimulation of blood vessels increases vasoconstriction. Sympathetic chain 5 Blood vessels
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Fig Copyright © McGraw-Hill Education. Permission required for reproduction or display. 3 4 Actions Reactions Baroreceptors in the carotid arteries and aorta detect an increase in blood pressure. Effectors Respond: Heart rate and stroke volume decrease; blood vessels dilate. The cardioregulatory center and the vasomotor center in the brain alter activity of the heart and blood vessels (baroreceptor reflex), and the adrenal medulla decreases secretion of epinephrine. 2 Homeostasis Disturbed: Blood pressure increases. Homeostas is Restored: Blood pressure decreases. 5 Blood pressure (normal range) 1 Start here Blood pressure (normal range) 6 Homeostasis Disturbed: Blood pressure decreases. Homeostasis Restored: Blood pressure increases. Actions Reactions Baroreceptors in the carotid arteries and aorta detect a decrease in blood pressure. Effectors Respond: Heart rate and stroke volume increase; blood vessels constrict. The cardioregulatory center and the vasomotor center in the brain alter activity of the heart and blood vessels (baroreceptor reflex), and the adrenal medulla increases secretion of epinephrine (adrenal medullary mechanism).
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Fig. 13.29 1 Chemoreceptors in the carotid and aortic bodies
Copyright © McGraw-Hill Education. Permission required for reproduction or display. 1 Chemoreceptors in the carotid and aortic bodies monitor blood O2, CO2, and pH. Carotid body chemoreceptors 1 Aortic body chemoreceptors Sensory nerves 2 Chemoreceptors in the medulla oblongata monitor blood CO2 and pH. Sensory nerves 3 3 Decreased blood O2, increased CO2, and decreased pH decrease parasympathetic stimulation of the heart, which increases the heart rate. 2 Chemoreceptors in the medulla oblongata Vagus nerve (parasympathetic) 4 4 Decreased blood O2, increased CO2, and decreased pH increase sympathetic stimulation of the heart, which increases the heart rate and stroke volume. Cardioregulatory and vasomotor centers in the medulla oblongata Sympathetic nerves 5 Decreased blood O2, increased CO2, and decreased pH increase sympathetic stimulation of blood vessels, which increases vasoconstriction. Sympathetic chain 5
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Fig. 13.30 1 Increased stimulation 1
Copyright © McGraw-Hill Education. Permission required for reproduction or display. 1 Increased stimulation 1 The same stimuli that increase sympathetic stimulation of the heart and blood vessels cause action potentials to be carried to the medulla oblongata. Medulla oblongata 2 Epinephrine and norepinephrine 2 Descending pathways from the medulla oblongata to the spinal cord increase sympathetic stimulation of the adrenal medulla, resulting in secretion of epinephrine and some norepinephrine. Spinal cord Sympathetic nerve fiber Adrenal medulla Sympathetic chain
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Fig Copyright © McGraw-Hill Education. Permission required for reproduction or display. Decreased blood pressure Liver 1 The kidneys detect decreased blood pressure, resulting in increased renin secretion. 1 Angiotensinogen Renin 2 2 Renin converts angiotensinogen, a protein secreted from the liver, to angiotensin I. Kidney Angiotensin I 6 3 Angiotensin-converting enzyme in lung capillaries 3 Angiotensin-converting enzyme in the lungs converts angiotensin I to angiotensin II. Aldosterone 4 Angiotensin II is a potent vasoconstrictor, resulting in increased blood pressure. 5 Angiotensin II Adrenal cortex 4 5 Angiotensin II stimulates the adrenal cortex to secrete aldosterone. Vasoconstriction 6 Aldosterone acts on the kidneys to increase Na+ reabsorption. As a result, urine volume decreases and blood volume increases, resulting in increased blood pressure. Increases water reabsorption and decreases urine volume Increased blood pressure
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Fig. 13.32 Baroreceptors (aortic arch, carotid sinus) detect decreased
Copyright © McGraw-Hill Education. Permission required for reproduction or display. Baroreceptors (aortic arch, carotid sinus) detect decreased blood pressure. Hypothalamic nerve cells detect increased osmotic pressure. Hypothalamic nerve cell Posterior pituitary ADH Increased reabsorption of water Blood vessel Kidney Vasoconstriction Increased blood volume Increased blood pressure
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pressure in right atrium
Fig Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Increased blood pressure in right atrium ANH Kidney Increased Na+ excretion and increased water loss result in decreased BP. ANH secretion
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Fig Copyright © McGraw-Hill Education. Permission required for reproduction or display. 3 4 A ctions R eactions Atrial natriuretic mechanism: Cardiac muscle cells detect increased atrial blood pressure; secretion of atrial natriuretic hormone increases. Effectors Respond: Vasodilation decreases peripheral resistance to blood flow. More Na+ and water are lost in the urine, decreasing blood volume. Renin-angiotensin-aldosterone mechanism: The kidneys detect increased blood pressure; production of angiotensin II and secretion of aldosterone from the adrenal cortex decrease. 2 Homeostasis Disturbed: Blood pressure increases. 5 Homeostasis Restored: Blood pressure decreases. Blood pressure (normal range) 1 Start here Blood pressure (normal range) 6 Homeostasis Disturbed: Blood pressure decreases. Homeostasis Restored: Blood pressure increases. Actions Reactions Renin-angiotensin-aldosterone mechanism: The kidneys detect decreased blood pressure; production of angiotensin II and secretion of aldosterone from the adrenal cortex increase. Effectors Respond: Vasoconstriction increases peripheral resistance to blood flow. Less Na+ and water are lost in the urine, increasing blood volume. ADH (vasopressin) mechanism: Baroreceptors detect decreased blood pressure, resulting in decreased stimulation of the hypothalamus and increased ADH secretion by the posterior pituitary.
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Atherosclerotic plaque
Fig Copyright © McGraw-Hill Education. Permission required for reproduction or display. Endothelium Vessel wall Atherosclerotic plaque
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