Topic 4 Cardiovascular System PDF

# Topic 4 Cardiovascular System ## Fundamentals of Anatomy & Physiology ### Eleventh Edition, Global Edition ## Chapter 20 ### The Heart - Lecture Presentation By Lori Garrett, Parkland College **Why would a Biomedical Engineer Need To Know About The Cardiovascular System?** - Cardiovascular Sys...

# Topic 4 Cardiovascular System ## Fundamentals of Anatomy & Physiology ### Eleventh Edition, Global Edition ## Chapter 20 ### The Heart - Lecture Presentation By Lori Garrett, Parkland College **Why would a Biomedical Engineer Need To Know About The Cardiovascular System?** - Cardiovascular System - Delivers oxygen and nutrients to tissues - Equalizes temperature in the body ## Cardiovascular System - Functions 1. Circulates Oxygen (removes carbon dioxide) 2. Provides cells with nutrients 3. Removes waste or toxic products 4. Protects against disease & infection via antibodies 5. Control body temperature ## 1-3 Organ Systems ### Cardiovascular **Major Organs:** - Heart - Blood - Blood Vessels **Functions:** - Distributes Blood cells, water, nutrients, waste products, oxygen, and carbon dioxide - Distributes heat to control body temperature ## Homeostasis ### Body Temperature Falls - Blood vessels constrict so that heat is conserved. Sweat glands do not secrete fluid. Shivering (involuntary contraction of muscles) generates heat, which warms the body. ### Body Temperature Rises - Blood vessels dilate, resulting in heat loss to the environment. Sweat glands secrete fluid. As the fluid evaporates, heat is lost from the body. ## An Introduction to The Heart ### Cardiovascular System - Heart - Blood - Blood Vessels ### The Heart - Beats approximately 100,000 times each day - Pumps about 8000 liters of blood per day ## 20-1 Anatomy of the Heart ### Pulmonary Circuit - Carries blood to and from gas exchange surfaces of lungs ### Systemic Circuit - Carries blood to and from the rest of the body ### Each Circuit Begins And Ends at the Heart - Blood travels through these circuits in sequence ## 20-1 Anatomy of the Heart ### Types of Blood Vessels #### Arteries - Carry blood away from heart #### Veins - Return blood to heart #### Capillaries (Exchange Vessels) - Interconnect smallest arteries and smallest veins - Exchange dissolved gases, nutrients, and wastes between blood and surrounding tissues. ## 20-1 Anatomy of the Heart ### Four Chambers of the Heart #### Right Atrium - Receives deoxygenated blood from systemic circuit #### Right Ventricle - Pumps deoxygenated blood into pulmonary circuit #### Left Atrium - Receives oxygenated blood from pulmonary circuit #### Left Ventricle - Pumps oxygenated blood into systemic circuit ## Blood Flow Through Heart & Lungs **A diagrammatic sectional view of the heart.** ### 20 -1 Anatomy of the Heart ### Heart - Great vessels connect at base (superior) - Pointed tip is apex (inferior) - Bits between two pleural cavities in mediastinum ### 20-1 Anatomy of the Heart #### Types of Blood Vessels #### Arteries - Carry blood away from heart #### Veins - Return blood to heart #### Capillaries (exchange vessels) - Interconnect smallest arteries and smallest veins - Exchange dissolved gases, nutrients, and wastes between blood and surrounding tissues. ## 20-1 Anatomy of the Heart ### Four Chambers of the Heart #### Right Atrium - Receives deoxygenated blood from systemic circuit #### Right Ventricle - Pumps deoxygenated blood into pulmonary circuit #### Left Atrium - Receives oxygenated blood from pulmonary circuit #### Left Ventricle - Pumps oxygenated blood into systemic circuit ## Blood Flow Through Heart & Lungs **A diagrammatic sectional view of the heart.** ### 20 -1 Anatomy of the Heart ### Heart - Great vessels connect at base (superior) - Pointed tip is apex (inferior) - Sits between two pleural cavities in mediastinum ### 20-1 Anatomy of the Heart #### Internal Anatomy and Organization - Chambers of heart are separated by muscular partitions (septa) - Interatrial septum - Separates atria - Interventricular septum - Separates ventricles - Much thicker than interatrial septum ### 20-1 Anatomy of the Heart ### Heart Valves - Prevent backflow of blood - Atrioventricular (AV) valves - Between atria and ventricles - When ventricles contract - Blood pressure closes valves - Papillary muscles contract and tense chordae tendineae - Prevents regurgitation (backflow) of blood into atria. ## 20-1 Anatomy of the Heart ### Atrioventricular (AV) Valves - Tricuspid and mitral valves - Folds of fibrous tissue that extend into openings between atria and ventricles - Permit blood flow in one direction - From right atrium to right ventricle - From left atrium to left ventricle ## 20-1 Anatomy of the Heart ### Semilunar Valves - Pulmonary and aortic valves - Prevent backflow of blood into ventricles - No muscular braces - Valvular heart disease (VHD) - Deterioration of valve function - May develop after carditis (inflammation of heart) - May result from rheumatic fever (inflammatory autoimmune response to streptococcal bacteria) ## 20-1 Anatomy of the Heart ### Coronary Circulation - Supplies blood to muscle tissue of heart - Coronary arteries - Originate at aortic sinuses - Elevated blood pressure and elastic rebound of aorta maintain blood flow through coronary arteries. ## 20-1 Anatomy of the Heart ### Coronary Artery Disease - Usual cause is formation of a fatty deposit, or atherosclerotic plaque, in the wall of a coronary vessel. - The plaque, or an associated thrombus (clot), narrows passageway and reduces blood flow. - Spasms in smooth muscles of vessel wall can further decrease or stop blood flow ## 20-1 Anatomy of the Heart ### Angina Pectoris - Commonly one of the first symptoms of CAD - A temporary ischemia develops when workload of heart increases. - Individual may feel comfortable at rest. - Exertion or emotional stress can produce sensations of pressure, chest construction, and pain. - Pain may radiate from sternal area to arms, back, and neck. ## 20-1 Anatomy of the Heart ### Myocardial Infarction (MI), or heart attack - Part of Coronary circulation becomes blocked. - Cardiac muscle cells due from lack of oxygen - Death of affected tissue creates a nonfunctional area known as an infarct - Most commonly results from severe CAD - Coronary thrombosis - Thrombus formation at a plaque - Most common cause of an MI ## 20-1 Anatomy of the Heart ### Myocardial Infarction - Consequences depend on site and nature of circulatory blockage. - If near the start of one of the coronary arteries - Damage will be widespread and heart may stop beating. - If blockage involves small arterial branch - Individual may survive the immediate crisis. - But may have complications such as reduced contractility and cardiac arrhythmias. ## 20-1 Anatomy of the Heart ### Treatment of CAD and Myocardial Infarction - About 25 percent of MI patients die before obtaining medical assistance - 65 percent of MI deaths among people under age 50 occur within an hour ## 20-1 Anatomy of the Heart ### Risk Factor Modification - Stop smoking - Treat high blood pressure - Adjust diet to lower cholesterol and promote weight loss - Reduce stress - Increase physical activity ## 20-1 Anatomy of the Heart ### Noninvasive Surgery #### Atherectomy - Long, slender catheter is inserted into coronary artery to remote plaque #### Balloon Angioplasty - Tip of catheter contains inflatable balloon - Inflated balloon presses plaque against vessel walls - Plaques commonly redevelop - A stent may be inserted to hold vessel open ## 20-1 Anatomy of the Heart ### Coronary Artery Bypass Graft (CABG) - Small section of another vessel is removed. - Used to create detour around obstructed portion of coronary artery. - Up to four coronary arteries can be rerouted during a singe operation. - Single, double, triple, or quadruple coronary bypasses. # Chapter 21 ## Blood Vessels and Circulation - Lecture Presentation By Lori Garrett, Parkland College ## Introduction to Blood Vessels and Circulation ### Blood Vessels - Classified by size and histological organizations - Instrumental in overall cardiovascular regulation ### The Largest Blood Vessels Attach to the Heart - Pulmonary trunk - Carries blood from right ventricle to pulmonary circulation - Aorta - Carries blood from left ventricle to systemic circulation ## The Five Main Types of Blood Vessels - Arteries - Arterioles - Capillaries - Veins - Venules ## 21-1 Blood Vessels ### Arteries - Carry blood away from heart ### Arterioles - Smallest branches of arteries that lead to capillary beds ### Capillaries - Smallest blood vessels with thin walls - Location of exchange between blood and interstitial fluid ## 21-1 Blood Vessels ### Venules - Smallest branches of veins that collect blood from capillaries ### Veins - Return blood to heart ## 21-1 Blood Vessels ### Vessel Walls Have Three Layers 1. Tunica Intima 2. Tunica Media 3. Tunica Externa ## 21-1 Blood Vessels ### Tunica Intima (inner Layer) - Includes - The endothelial lining - Connective tissue layer - Internal elastic membrane (in arteries) - Elastic fibers in outer margin of tunica intima ## 21-1 Blood Vessels ### Tunica Media (middle layer) - Contains concentric sheets of smooth muscle in loose connective tissue. - Encircles the endothelium that lines the lumen. - Binds to inner and outer layers - External elastic membrane - Separates tunica media from tunica externa ## 21-1 Blood Vessels ### Tunica Externa (outer layer) - Anchors Vessel to adjacent tissues - Contains - Collagen fibers - Elastic fibers - Smooth muscle (in veins) ## 21-1 Arteries vs Veins ### Differences Between Arteries and Veins - Arteries have thicker walls and higher blood pressure than veins - A constricted artery has a small, round lumen - A vein has a large, irregular lumen - The endothelium of a constricted artery is folded - Arteries are more elastic than veins - Veins have valves ## 21-1 Structure and Function of Arteries ### Elastic Arteries (conducting arteries) - Large vessels (e.g., pulmonary trunk and aorta) - Tunica media has many elastic fibers and few muscle cells. - Elasticity evens out pulse force ## 21-1 Structure and Function of Arteries ### Muscular Arteries (distribution arteries) - Most arteries are medium-sized muscular arteries - Tunica media has many muscle cells. ### Arterioles (resistance vessels) - Small vessels - Have little or no tunica externa - Have thin or incomplete tunica media ## Arteries and Arterioles - No valves - High pressure oxygenated blood from the heart to the tissues - The largest artery in the body is the aorta ## 21-1 Structure and Function of Capillaries ### Capillaries - Smallest vessels with thin walls - Microscopic capillary networks permeate all active tissues ### Capillary function - Location of all exchange functions of cardiovascular system - Materials diffuse between blood and interstitial fluid ## Capillaries - Capillaries are the functional units of the vascular system. - Composed of a single layer of endothelial cells, they are just thin enough to allow red blood cells to squeeze through their wall. - No valves ## 21-1 Structure and Function of Capillaries ### Capillary Structure - Endothelial tube, inside thin basement membrane - No tunica media - No tunica externa - Diameter is similar to that of a red blood cell. ## 21-1 Structure and Function of Capillaries ### Capillary Beds (capillary plexus) - Connect one arteriole and one venule. - Precapillary sphincter - Guards entrance to each capillary - Opens and closes, causing capillary blood to flow in pulses. ### Thoroughfare Channels - Direct capillary connections between arterioles and venules ## 21-1 Structure and Function of Capillaries ### Collaterals - Multiple arteries that contribute to one capillary bed. - Allow circulation if one artery is blocked. - Arterial anastomosis - Fusion of two collateral arteries - Arteriovenous anastomoses - Direct connections between arterioles and venules - Bypass the capillary bed. ## 21-1 Structure and Function of Veins ### Veins - Collect blood from capillaries and return it to heart - Compared to arteries, veins have - Larger diameters - Thinner walls - Lower blood pressure - Valves to stop backflow ## 21-1 Structure and Function of Veins ### Large Veins - Have all three tunica layers. - Thick tunica externa - Thin tunica media ### Venous Valves - Folds of tunica intima. - Prevent blood from flowing backward - Compression of veins pushes blood toward heart - When walls of veins near the valves weaken, varicose veins or hemorrhoids may result. ## 21-1 Structure and Function of Veins ### Venules - Very small veins - Collect blood from capillaries ### Medium-Sized Veins - Thin tunica media and few smooth muscle cells - Tunica extrema contains longitudinal bundles of elastic fibers. ## 21-1 Arteries VS Veins ### Differences Between Arteries And Veins - Arteries have thicker walls and higher blood pressure than veins - A constricted artery has a small, round lumen. - A vein has a large, irregular lumen. - The endothelium of a constricted artery is folded - Arteries are more elastic than veins - Veins have valves ## 21-1 Structure and Function of Arteries ### Aneurysm - A bulge in an arterial wall - Caused by weak spot in elastic fibers - Pressure may rupture vessel. ## 21-1 Structure and Function of Arteries ### Arteries - Elasticity allows arteries to absorb pressure waves that come with each heartbeat. - Contractility - Arteries change diameter - Controlled by sympathetic division of ANS - Vascoconstriction - Contraction of arterial smooth muscle - Vasodilation - Relaxation of arterial smooth muscle - Enlarges the lumen ## 21-1 Structure and Function of Arteries ### Vasoconstriction and Vasodilation - Affect - Afterload on heart - Peripheral blood pressure - Capillary blood flow ## 21-2 Pressure and Resistance ### Vascular Resistance - Due to friction between blood and vessel walls - Depends on vessel length and vessel diameter - Adult vessel length is constant - Vessel diameter varies by vasodilation and vasoconstriction - R increases exponentially as vessel diameter decreases. ## 21-2 Pressure and Resistance ### Blood Viscosity - R caused by molecules and suspended materials in a liquid - Whole blood viscosity is about four times that of water ## 21-2 Pressure and Resistance ### Turbulence - Swirling action that disturbs smooth flow of liquid - Occurs in heart chambers and great vessels - Athersclerotic plaques cause abnormal turbulence ## 21-1 Blood Vessels ### Capacitance of a blood vessel - The ability to stretch. - Relationship between blood volume and pressure - Veins (capacitance vessels) stretch more than arteries. - Act as blood reservoirs ### Systemic veins constrict (venoconstriction) in response to blood loss - Increasing amount of blood in arterial system and capillaries. ## 21-1 Blood Pressure - Resistance to blood flow depends on only three variables: viscosity n, vessel length λ, and radius r. ## 21-5 Pulmonary and Systemic Circulation ### Three General Functional Patterns 1. Peripheral artery and vein distribution is the same on right and left, except near the heart. 2. The same vessel may have different names in different locations. 3. Tissues and organs usually have multiple arteries and veins. - Vessels may be interconnected with anastomoses. ## 21-1 Blood Vessels ### The distribution of blood - Heart, arteries, and capillaries. - 30-35 percent of blood volume - Venous system. - 65-70 percent - One-third of venous blood is in large venous networks of the liver, bone marrow, and skin. ## Pulmonary ad Systemic Circulation ### Pulmonary Circuit (Yellow Arrows) 6. Blood flows from the right atrium to the right ventricle and is then pumped into the pulmonary trunk. 7. The pulmonary trunk conducts deoxygenated blood into pulmonary arteries to the lungs. 8. The blood passes through smaller and smaller arteries before entering pulmonary capillaries for gas exchange. 9. Oxygenated blood exits the lung via a series of progressively larger veins that merge to form the pulmonary veins. 10. Pulmonary veins drain into the left atrium. 11. Blood enters the left ventricle from the left atrium. The cycle repeats. ### Systemic Circuit (Black Arrows) 1. Oxygenated blood is pumped form the left atrium to the left ventricle and then into the aorta. 2. Blood passes from the aorta into elastic arteries and then into muscular arteries before entering aterioles. 3. Blood in aterioles enters systemic capillaries for exchange of gases and nutrients. 4. Deoxygenated blood exits capillary beds into venules and then into veins. 5. Deoxygenated blood is conducted to either the superior or inferior vena cava and then enters the right atrium of the heart. ## 21-6 The Pulmonary Circuit ### Learning Outcome: Identify the major arteries and veins of the pulmonary circuit. - Deoxygenated blood arrives at heart from systemic circuit - Passes through right atrium and right ventricle - Enters pulmonary trunk - At the lungs - CO2 is removed. - O2 is added. - Oxygenated blood - Returns to the heart - Is distributed to systemic circuit ## 21-6 The Pulmonary Circuit ### Pulmonary Arteries - Carry deoxygenated blood. - Pulmonary trunk - Branches into left and right pulmonary arteries. - Pulmonary arteries - Branch into pulmonary arterioles. - Pulmonary arterioles - Branch into capillary networks that surround alveoli. ## 21-6 The Pulmonary Circuit ### Pulmonary Veins - Carry oxygenated blood - Capillary networks around alveoli - Join to form venules. - Venules - Join to form four pulmonary veins. - Pulmonary veins: - Empty into left atrium. ## 21-7 The Systemic Circuit ### The Systemic Circuit - Contains 84 percent of blood volume - Supplies entire body - Except for pulmonary circuit ### Systemic Arteries - Carry blood from left ventricle - Into ascending aorta - Coronary arteries - Branch from aortic sinus ## Branches of the Aortic Arch: Head and Neck Arteries - Bronches of common carotid arteries - Internal carotid arteries - External carotid arteries - Branches of the subclavian arteries - Left and right vertebral arteries - Internal carotids and vertebral arteries supply brain ## Veins of Head and Neck - Vertebral veins - Travel with vertebral artery through transverse foramina of cervicals - Drain cervicals, spinal cord, deep neck muscles ## Veins of the Shoulder and Upper Limb ### Deep Veins - Radial and ulnar veins (paired) - Brachial vein that connects with axillary vein ### Superficial Veins - Basilic vein (becomes axillary vein) - Cephalic vein - Axillary vein becomes subclavian vein beneath clavicle. ## Branches of the Aortic Arch: Arteries of Upper Limb and Shoulder - Three major arteries - Subclavian - Axillary - Brachial - Subclavian is posterior to clavicle - Axillary is within axillary region (armpit). - Brachial is within brachium (arm) ## Branches of the Descending Aorta: Arteries of the Abdominal Aorta - Three major branches (in order from superior to inferior along abdominal aorta.) - Celiac trunk - Superior mesenteric artery - Inferior mesenteric artery ## Veins of Abdomen and Pelvis - Left common iliac vein - Left external iliac vein - Left internal iliac vein - Left femoral vein ## Hepatic Portal System - Portal system - Begins and ends in capillaries - Heart not part of system - Hepatic portal system - Begins with viscera of gastrointestinal tract - Ends with liver ## Branches of The Descending Aorta: Pelvis and Lower Limb - Abdominal aorta divides into: - Common iliac arteries - Common iliac arteries divide into: - External iliac arteries - Internal iliac arteries - Popliteal artery - Anterior and posterior tibial arteries. ## Veins of Pelvis and Lower Limb ### Deep Veins - Anterior and posterior tibial veins - Popliteal vein - Femoral vein ### Superficial Veins - Great saphenous vein - External iliac vein - Internal iliac vein ## 21-9 Effects of Aging on the Cardiovascular System - Cardiovascular capabilities decline with age. ### Age-Related Changes Occur in - Blood - Heart - Blood Vessels ## 21-9 Effects of Aging on the Cardiovascular System ### Age-Related Changes in the Heart - Reduced maximum cardiac output - Changes in nodal and conducting cells - Reduced elasticity of cardiac (fibrous) skeleton - Progressive atherosclerosis - Replacement of damaged cardiac muscle cells by scar tissue ## 21-9 Effects Of Aging on the Cardiovascular System ### Age-Related Changes in Blood 1. Decreased hematocrit 2. Peripheral blockage by blood clot (thrombus) 3. Pooling of blood in legs. - Due to venous valve deterioration ## 21-9 Effects of Aging on the Cardiovascular System ### Age-Related Changes in Blood Vessels 1. Arteries become less elastic - Pressure change can cause aneurysm 2. Calcium deposits on vessel walls - Can cause stroke or infarction 3. Lipid deposits in tunica media, and calcium salts can form atherosclerotic plaques. 4. Thrombi can form at atherosclerotic plaques. ## 21-9 Cardiovascular System Integration - Disorders of the cardiovascular system my: - Affect many cells and systems - Be structural or functional - Result from disease or trauma ## Integration of the CARDIOVASCULAR System with other Body Systems **Integumentary system** - Trigger localized changes in blood flow and capillary permeability. **Skeletal system** - Provides calcium needed for normal cardiac muscle contraction and protects blood cells developing in red bone marrow. **Nervous system** - Controls patterns of circulation in peripheral tissues. **Endocrine system** - Produces erythropoietin, which regulates production of RBCs. **Muscular system** - Assists venous circulation through skeletal muscle contractions. **Cardiovascular system** - Carries vital substances like oxygen and nutrients to the rest of the body. ## Interaction of the circulatory system with other body systems - **Digestive system:** Absorbs nutrients and water. - **Endocrine system:** Delivers hormones. - **Integumentary system:** Carries clotting factors, platelets, and white blood cells. - **Lymphatic system:** Transports white blood cells and immunoglobulins. - **Muscular system:** Provides nutrients and oxygen. - **Nervous system:** Produces cerebrospinal fluid. - **Reproductive system:** Aids in erection of genitalia. - **Respiratory system:** Provides blood for gas exchange. - **Skeletal system:** Provides calcium and phosphate. - **Urinary system:** Delivers 20% of resting circulation to kidneys.