The Cardiovascular System: Blood Vessels and Circulation

The Structure of Blood Vessels Blood Vessel Review Arteries carry blood away from the heart Pulmonary trunk to lungs Aorta to everything else Microcirculation is where exchange occurs Arterioles to feed the capillaries Capillaries exchange with the tissues Venules to receive capillary blood Veins bring it back to the heart Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

The Structure of Blood Vessels A Comparison of a Typical Artery and a Typical Vein Figure 13-1

The Structure of Blood Vessels Arteries and Veins Have Three Layers Tunica interna Innermost layer (endothelium) in contact with blood Tunica media Middle layer of smooth muscle Vasoconstrict or vasodilate Tunica externa Outer layer of loose connective tissue Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

The Structure of Blood Vessels X Types of Arteries Elastic arteries Largest Closest to heart Stretch during systole Recoil during diastole Muscular arteries Arterioles Tiny branches of small arteries Feeders of capillary networks Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

The Structure of Blood Vessels X The Structure of the Various Types of Blood Vessels Figure 13-2

The Structure of Blood Vessels Properties of Capillaries Where exchange between blood and cells takes place Organized into interconnected capillary beds Precapillary sphincters (bands of smooth muscle) controls flow

The Structure of Blood Vessels Figure 13-4(a) The Organization of a Capillary Bed

The Structure of Blood Vessels The Organization of a Capillary Bed Figure 13-4(b)

The Structure of Blood Vessels Properties of Veins Collect blood from capillaries Merge into medium-sized veins Merge then into large veins Blood pressure is low here Valves keep blood flowing toward the heart Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

The Structure of Blood Vessels The Function of Valves in the Venous System Figure 13-5

Circulatory Physiology Factors Affecting Blood Flow Pressure Flow goes up as pressure difference goes up Flow goes from higher to lower pressure Regulated by nervous and endocrine systems Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Circulatory Physiology Factors Affecting Blood Flow Peripheral resistance Flow goes down as resistance goes up Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Circulatory Physiology Control of Peripheral Resistance Consists of three components: Vascular resistance Goes up as diameter is reduced Arteriole diameter dominates Viscosity of blood Depends on hematocrit Turbulence Cause of pathological sounds Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Circulatory Physiology Pressures in the Systemic Circuit Arterial pressure Overcomes peripheral resistance to maintain flow to the organs Capillary pressure Excessive pressure causes edema Venous pressure Low pressure that drives venous return Affects cardiac output and peripheral flow Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Circulatory Physiology Arterial Pressure Rises during ventricular systole Falls during ventricular diastole Pulse pressure is difference between systolic pressure and diastolic pressure Lessens with distance from heart Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Circulatory Physiology Pressures Within the Circulatory System Figure 13-6

Circulatory Physiology Checking the Pulse and Blood Pressure Figure 13-8(a)

Circulatory Physiology Checking the Pulse and Blood Pressure Figure 13-8(b)

Circulatory Physiology Functions of Capillary Exchange Maintain communication between plasma and interstitial fluid Speed the distribution of nutrients, hormones, and dissolved gases Flush antigens to lymphoid tissue Aid movement of proteins Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Circulatory Physiology Dynamics of Capillary Exchange Small molecules diffuse across endothelium Water follows osmotically Balance of forces determines direction of filtration Capillary pressure forces fluid out Protein osmotic pressure pulls fluid in Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Circulatory Physiology Figure 13-7 Forces Acting Across Capillary Walls

Circulatory Physiology Factors Assisting Venous Return Low venous resistance Valves in veins Compression of veins by muscular contraction Respiratory pump pulls blood into thorax Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Circulatory Physiology Key Note Blood flow is the goal. Total peripheral blood flow is equal to cardiac output. Blood pressure is needed to overcome friction to sustain blood flow. If blood pressure is too low, vessels collapse, blood flow stops, and tissues die; if too high, vessel walls stiffen and capillary beds may rupture. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Cardiovascular Regulation Factors Affecting Tissue Blood Flow Cardiac output Peripheral resistance Blood pressure Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Cardiovascular Regulation Homeostasis of Tissue Perfusion Autoregulation Local control of pre-capillary sphincters CNS control Responds to blood pressure, blood gases Hormone control Short-term adjustments Blood pressure Peripheral resistance Long-term adjustments Blood volume Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Cardiovascular Regulation Local, Neural, and Endocrine Adjustments That Maintain Blood Pressure and Blood Flow Figure 13-9

Cardiovascular Regulation Neural Control of Blood Flow and Pressure Baroreceptor reflexes Adjust cardiac output and peripheral resistance to maintain normal blood pressure Driven by baroreceptors Aortic sinus Carotid sinus Atrial baroreceptors Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Cardiovascular Regulation Neural Control of Blood Flow and Pressure Chemoreceptor reflexes Respond to changes in CO 2, O 2 and pH Sense blood and cerebrospinal fluid Impact cardioacceleratory, cardioinhibitory and vasomotor centers Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Figure of 12 Blood pressure reduced Decreased cardiac output Vasodilation occurs HOMEOSTASIS RESTORED HOMEOSTASIS DISTURBED Blood pressure rises above normal range Vasomotor centers inhibited Cardioinhibitory centers stimulated Cardioacceleratory centers inhibited REFLEX RESPONSE Baroreceptors stimulated Inhibition REFLEX RESPONSE Baroreceptors inhibited HOMEOSTASIS DISTURBED Blood pressure falls below normal range HOMEOSTASIS Normal range of blood pressure HOMEOSTASIS RESTORED Vasomotor centers stimulated Cardioinhibitory centers inhibited Cardioacceleratory centers stimulated Vasoconstriction occurs Increased cardiac output Blood pressure elevated

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure of 12 HOMEOSTASIS DISTURBED Blood pressure rises above normal range HOMEOSTASIS Normal range of blood pressure

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure of 12 HOMEOSTASIS DISTURBED Blood pressure rises above normal range Cardioinhibitory centers stimulated Cardioacceleratory centers inhibited REFLEX RESPONSE Baroreceptors stimulated Inhibition HOMEOSTASIS Normal range of blood pressure

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure of 12 Decreased cardiac output HOMEOSTASIS DISTURBED Blood pressure rises above normal range Cardioinhibitory centers stimulated Cardioacceleratory centers inhibited REFLEX RESPONSE Baroreceptors stimulated Inhibition HOMEOSTASIS Normal range of blood pressure

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure of 12 Decreased cardiac output Vasodilation occurs HOMEOSTASIS DISTURBED Blood pressure rises above normal range Vasomotor centers inhibited Cardioinhibitory centers stimulated Cardioacceleratory centers inhibited REFLEX RESPONSE Baroreceptors stimulated Inhibition HOMEOSTASIS Normal range of blood pressure

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure of 12 Blood pressure reduced Decreased cardiac output Vasodilation occurs HOMEOSTASIS RESTORED HOMEOSTASIS DISTURBED Blood pressure rises above normal range Vasomotor centers inhibited Cardioinhibitory centers stimulated Cardioacceleratory centers inhibited REFLEX RESPONSE Baroreceptors stimulated Inhibition HOMEOSTASIS Normal range of blood pressure

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure of 12 HOMEOSTASIS DISTURBED HOMEOSTASIS Normal range of blood pressure Blood pressure falls below normal range

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure of 12 HOMEOSTASIS DISTURBED Cardioinhibitory centers inhibited Cardioacceleratory centers stimulated REFLEX RESPONSE Baroreceptors inhibited Inhibition HOMEOSTASIS Normal range of blood pressure Blood pressure falls below normal range

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure of 12 Increased cardiac output HOMEOSTASIS DISTURBED Cardioinhibitory centers inhibited Cardioacceleratory centers stimulated REFLEX RESPONSE Baroreceptors inhibited Inhibition HOMEOSTASIS Normal range of blood pressure Blood pressure falls below normal range

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure of 12 Increased cardiac output Vasoconstriction occurs HOMEOSTASIS DISTURBED Vasomotor centers stimulated Cardioinhibitory centers inhibited Cardioacceleratory centers stimulated REFLEX RESPONSE Baroreceptors inhibited Inhibition HOMEOSTASIS Normal range of blood pressure Blood pressure falls below normal range

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure of 12 Blood pressure elevated Increased cardiac output Vasoconstriction occurs HOMEOSTASIS RESTORED HOMEOSTASIS DISTURBED Vasomotor centers stimulated Cardioinhibitory centers inhibited Cardioacceleratory centers stimulated REFLEX RESPONSE Baroreceptors inhibited Inhibition HOMEOSTASIS Normal range of blood pressure Blood pressure falls below normal range

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure of 12 Blood pressure reduced Decreased cardiac output Vasodilation occurs HOMEOSTASIS RESTORED HOMEOSTASIS DISTURBED Blood pressure rises above normal range Vasomotor centers inhibited Cardioinhibitory centers stimulated Cardioacceleratory centers inhibited REFLEX RESPONSE Baroreceptors stimulated Inhibition REFLEX RESPONSE Baroreceptors inhibited HOMEOSTASIS DISTURBED Blood pressure falls below normal range HOMEOSTASIS Normal range of blood pressure HOMEOSTASIS RESTORED Vasomotor centers stimulated Cardioinhibitory centers inhibited Cardioacceleratory centers stimulated Vasoconstriction occurs Increased cardiac output Blood pressure elevated

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings HOMEOSTASIS DISTURBED Decreased pH and O 2 levels, elevated CO 2 levels in blood and CSF HOMEOSTASIS Normal pH, O 2, and CO 2 levels in blood and CSF REFLEX RESPONSE Chemoreceptors stimulated Cardioacceleratory centers stimulated Cardioinhibitory centers inhibited Vasomotor centers stimulated Increased cardiac output and blood pressure Vasoconstriction occurs Increased pH and O 2 levels, decreased CO 2 levels in blood HOMEOSTASIS RESTORED Inhibition Respiratory centers stimulated Respiratory rate increases Figure of 6

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings HOMEOSTASIS DISTURBED Decreased pH and O 2 levels, elevated CO 2 levels in blood and CSF HOMEOSTASIS Normal pH, O 2, and CO 2 levels in blood and CSF Figure of 6

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings HOMEOSTASIS DISTURBED Decreased pH and O 2 levels, elevated CO 2 levels in blood and CSF HOMEOSTASIS Normal pH, O 2, and CO 2 levels in blood and CSF REFLEX RESPONSE Chemoreceptors stimulated Cardioacceleratory centers stimulated Cardioinhibitory centers inhibited Inhibition Figure of 6

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings HOMEOSTASIS DISTURBED Decreased pH and O 2 levels, elevated CO 2 levels in blood and CSF HOMEOSTASIS Normal pH, O 2, and CO 2 levels in blood and CSF REFLEX RESPONSE Chemoreceptors stimulated Cardioacceleratory centers stimulated Cardioinhibitory centers inhibited Vasomotor centers stimulated Increased cardiac output and blood pressure Vasoconstriction occurs Inhibition Figure of 6

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings HOMEOSTASIS DISTURBED Decreased pH and O 2 levels, elevated CO 2 levels in blood and CSF HOMEOSTASIS Normal pH, O 2, and CO 2 levels in blood and CSF REFLEX RESPONSE Chemoreceptors stimulated Cardioacceleratory centers stimulated Cardioinhibitory centers inhibited Vasomotor centers stimulated Increased cardiac output and blood pressure Vasoconstriction occurs Inhibition Respiratory centers stimulated Respiratory rate increases Figure of 6

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings HOMEOSTASIS DISTURBED Decreased pH and O 2 levels, elevated CO 2 levels in blood and CSF HOMEOSTASIS Normal pH, O 2, and CO 2 levels in blood and CSF REFLEX RESPONSE Chemoreceptors stimulated Cardioacceleratory centers stimulated Cardioinhibitory centers inhibited Vasomotor centers stimulated Increased cardiac output and blood pressure Vasoconstriction occurs Increased pH and O 2 levels, decreased CO 2 levels in blood HOMEOSTASIS RESTORED Inhibition Respiratory centers stimulated Respiratory rate increases Figure of 6

Cardiovascular Regulation The Hormonal Regulation of Blood Pressure and Blood Volume Figure 13-12(a)

Cardiovascular Regulation Figure 13-12(b) The Hormonal Regulation of Blood Pressure and Blood Volume

Cardiovascular Regulation X Hormonal CV Regulation Short-term regulation Epinephrine from adrenal medulla Cardiac output and peripheral resistance Long-term regulation Antidiuretic Hormone (ADH) Angiotensin II Erythropoietin (EPO) Atrial natriuretic peptide (ANP) Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Cardiovascular Regulation X Hormone Effects on CV Regulation ADH, angiotensin II promote vasoconstriction ADH, aldosterone promote water, salt retention EPO stimulates RBC production ANP promotes sodium, water loss Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Cardiovascular Regulation Key Note Cardiac output cannot be increased indefinitely, and so blood flow to active tissues must be increased and flow to inactive tissue reduced. A combination of autoregulation, neural regulation, and hormone release accomplish this. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Patterns of CV Response Exercise and the Cardiovascular System Cardiac output rises Blood flow to skeletal muscle increases Flow to non-essential organs falls Exercise produces long-term benefits Larger stroke volumes Slower resting heart rates Greater cardiac reserves Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Patterns of CV Response X Response to Hemorrhage (Blood Loss) Increase in cardiac output Mobilization of venous reserves Peripheral vasoconstriction Release of hormones that defend blood volume Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

The Blood Vessels Vessels of the Pulmonary Circuit Pulmonary trunk From right ventricle to lungs Pulmonary arteries (left and right) Pulmonary veins (left and right) To left atrium Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

The Blood Vessels An Overview of the Pattern of Circulation Figure 13-13

The Blood Vessels Figure The Pulmonary Circuit

The Blood Vessels The Systemic Circulation Ascending aorta From left ventricle Feeds coronary circulation Aortic arch Feeds shoulders, neck, head Descending aorta Feeds inferior body regions Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

The Blood Vessels An Overview of the Arterial System Figure 13-15

The Blood Vessels Arteries of the Chest and Upper Limb Figure 13-16

The Blood Vessels A Flow Chart Showing the Arterial Distribution to the Head, Chest, and Upper Limbs Figure 13-17

The Blood Vessels Arteries of the Neck, Head, and Brain Figure 13-18

The Blood Vessels Figure 13-19(a) Major Arteries of the Trunk

The Blood Vessels Figure 13-19(b) Major Arteries of the Trunk

The Blood Vessels X Anatomy of Arterial Supply Contrasts with Venous Drainage Major arteries in neck and limbs all lie deep Major veins form a dual-venous drainage Are either superficial or deep Serves temperature control needs Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

The Blood Vessels Anatomy of Venous Drainage Superior vena cava Drains head, neck, shoulders, arms, chest Inferior vena cava Drains most of body below diaphragm Hepatic portal vein Carries blood draining the digestive system to the liver for purification and storage of absorbed nutrients Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

The Blood Vessels An Overview of the Venous System Figure 13-20

The Blood Vessels Major Veins of the Head and Neck Figure 13-21

The Blood Vessels The Venous Drainage of the Abdomen and Chest Figure 13-22

The Blood Vessels A Flow Chart of the Circulation to the Superior and Inferior Venae Cavae Figure 13-23(a)

The Blood Vessels A Flow Chart of the Circulation to the Superior and Inferior Venae Cavae Figure 13-23(b)

The Blood Vessels The Hepatic Portal System Figure 13-24

The Blood Vessels Fetal Circulation Placenta Receives two umbilical arteries from fetus Drained by one umbilical vein to the fetus Joins ductus venosus in liver Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

The Blood Vessels Fetal Circulation Pulmonary bypass Lets blood flow skip the lungs Foramen ovale Between atria in interatrial septum Becomes fossa ovalis in adult Ductus arteriosus Between pulmonary trunk and aorta Both pathways close after birth Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

The Blood Vessels Fetal Circulation Figure 13-25(a)

The Blood Vessels Fetal Circulation Figure 13-25(b)

Aging and the CV System Age Related Changes in the Blood Decreased hematocrit Vessel blockage by a thrombus (blood clot) Pooling in the legs resulting from faulty valves Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Aging and the CV System Age Related Changes in the Heart Reduction in maximal cardiac output Impaired nodal and conduction function Stiffening of cardiac skeleton Retricted coronary flow due to atherosclerosis Fibrous replacement of damaged myocardium Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Aging and the CV System Age Related Changes in Blood Vessels Embrittlement of arterial walls by arteriosclerosis Increased risk of aneurism Calcium deposits in lumen Increased risk of thrombus Thrombus formation at atherosclerotic plaques Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

The Cardiovascular System in Perspective FIGURE Functional Relationships Between the Cardiovascular System and Other Systems Figure of 11 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Figure of 11 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Stimulation of mast cells produces localized changes in blood flow and capillary permeability Delivers immune system cells to injury sites; clotting response seals breaks in skin surface; carries away toxins from sites of infection; provides heat The Integumentary System

Figure of 11 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Skeletal System Provides calcium needed for normal cardiac muscle contraction; protects blood cells developing in bone marrow Provides calcium and phosphate for bone deposition; delivers EPO to bone marrow, parathyroid hormone, and calcitonin to osteoblasts and osteoclasts

Figure of 11 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Muscular System Skeletal muscle contractions assist in moving blood through veins; protects superficial blood vessels, especially in neck and limbs Delivers oxygen and nutrients, removes carbon dioxide, lactic acid, and heat during skeletal muscle activity

Figure of 11 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Nervous System Controls patterns of circulation in peripheral tissues; modifies heart rate and regulates blood pressure; releases ADH Endothelial cells maintain blood-brain barrier; help generate CSF

Figure of 11 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Endocrine System Erythropoietin regulates production of RBCs; several hormones elevate blood pressure; epinephrine stimulates cardiac muscle, elevating heart rate and contractile force Distributes hormones throughout the body; heart secretes ANP

Figure of 11 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Lymphatic System Defends against pathogens or toxins in blood; fights infections of cardiovascular organs; returns tissue fluid to circulation Distributes WBCs; carries antibodies that attack pathogens; clotting response assists in restricting spread of pathogens; granulocytes and lymphocytes produced in bone marrow

Figure of 11 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Respiratory System Provides oxygen to cardiovascular organs and removes carbon dioxide RBCs transport oxygen and carbon dioxide between lungs and peripheral tissues

Figure of 11 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Digestive System Provides nutrients to cardiovascular organs; absorbs water and ions essential to maintenance of normal blood volume Distributes digestive tract hormones; carries nutrients, water, and ions away from sites of absorption; delivers nutrients and toxins to liver

Figure of 11 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Urinary System Releases renin to elevate blood pressure and erythropoietin to accelerate red blood cell production Delivers blood to capillaries, where filtration occurs; accepts fluids and solutes reabsorbed during urine production

Figure of 11 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Reproductive System Sex hormones maintain healthy vessels, estrogen slows development of atherosclerosis Distributes reproductive hormones; provides nutrients, oxygen, and waste removal for developing fetus; local blood pressure changes responsible for physical changes during sexual arousal