CHAPTER © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 23 The Cardiovascular System

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Learning Outcomes 23.1Describe the structure of the heart and the function of each part. 23.2Trace the flow of blood through the heart. 23.3List the most common heart sounds and what events produce them. 23.4Explain how heart rate is controlled by the electrical conduction system of the heart.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Learning Outcomes (cont.) 23.5List the different types of blood vessels and describe the functions of each. 23.6Define blood pressure and tell how it is controlled. 23.7Trace the flow of blood through the pulmonary and systemic circulation. 23.8List the major arteries and veins of the body and describe their locations.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Learning Outcomes (cont.) 23.9List and describe the components of blood Give the functions of red blood cells, the different types of white blood cells, and platelets List the substances normally found in plasma Explain how bleeding is controlled Explain the differences among blood types A, B, AB, and O.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Learning Outcomes (cont.) 23.14Explain the difference between Rh-positive blood and Rh-negative blood Explain the importance of blood typing and tell which blood types are compatible Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the cardiovascular system.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Introduction The cardiovascular system consists of heart and blood vessels Sends blood to –Lungs for oxygen –Digestive system for nutrients Also circulates waste products to certain organ systems for removal from the blood

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Structures of the Heart Cone-shaped organ about the size of a loose fist In the mediastinum Extends from the level of the second rib to about the level of the sixth rib Slightly left of the midline

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Structures of the Heart (cont.)  Heart is bordered: Laterally by the lungs Posteriorly by the vertebral column Anteriorly by the sternum  Rests on the diaphragm inferiorly

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Structures of the Heart (cont.) Heart coverings –Pericardium Covers the heart and large blood vessels attached to the heart Visceral pericardium –Innermost layer –Directly on the heart Parietal pericardium –Layer on top of the visceral pericardium Heart walls: –Epicardium Outermost layer Fat to cushion heart –Myocardium Middle layer Primarily cardiac muscle –Endocardium Innermost layer Thin and smooth Stretches as the heart pumps Click for Larger View

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Back

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Structures of the Heart (cont.) Four chambers –Two atria Upper chambers Left and right Separated by interatrial septum –Two ventricles Lower chambers Left and right Separated by interventricular septum Click for View of Heart Atrioventricular septum separates the atria from the ventricles

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Structures of the Heart (cont.) Tricuspid valve – prevents blood from flowing back into the right atrium when the right ventricle contracts Bicuspid (mitral) valve – prevents blood from flowing back into the left atrium when the left ventricle contracts Pulmonary semilunar valve – prevents blood from flowing back into the right ventricle Aortic semilunar valve – prevents blood from flowing back into the left ventricle Click for View of Heart

© 2011 The McGraw-Hill Companies, Inc. All rights reserved The Heart Labeled Back

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Blood Flow Through the Heart Deoxygenated blood in from body Oxygenated blood in lungs Atria ContractVentricles Contract Deoxygenated blood out to lungs Oxygenated blood out to body

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Blood Flow Through the Heart (cont.) Right Atrium Right Ventricle Pulmonary Semilunar Valve Left Atrium Bicuspid Valve Left Ventricle Pulmonary Valve Tricuspid Valve Lungs Body Aortic Semilunar Valve

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Cardiac Cycle Right atrium contracts –Tricuspid valve opens –Blood fills right ventricle Right ventricle contracts –Tricuspid valve closes –Pulmonary semilunar valve opens –Blood flows into pulmonary artery Left atrium contracts –Bicuspid valve opens –Blood fills left ventricle Left ventricle contracts –Bicuspid valve closes –Aortic semilunar valve opens –Blood pushed into aorta  One heartbeat = one cardiac cycle Atria contract and relax Ventricles contract and relax

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Cardiac Cycle (cont.) Influenced by –Exercise –Parasympathetic nerves –Sympathetic nerves –Cardiac control center –Body temperature –Potassium ions –Calcium ions

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Heart Sounds One cardiac cycle – two heart sounds (lubb and dubb) when valves in the heart snap shut –Lubb – first sound When the ventricles contract, the tricuspid and bicuspid valves snap shut –Dubb – second sound When the atria contract and the pulmonary and aortic valves snap shut

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Cardiac Conduction System Group of structures that send electrical impulses through the heart Sinoatrial node (SA node) –Wall of right atrium –Generates impulse –Natural pacemaker –Sends impulse to AV node Atrioventricular node (AV node) –Between atria just above ventricles –Atria contract –Sends impulse to the bundle of His Bundle of His –Between ventricles –Two branches –Sends impulse to Purkinje fibers Purkinje fibers –Lateral walls of ventricles –Ventricles contract Click the i below for a Diagram

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Cardiac Conduction System Back

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Apply Your Knowledge Match the following: __ Tricuspid valveA.Two branches; sends impulse to Purkinje fibers __ Bicuspid valveB.Covering of the heart and aorta __ PericardiumC.Between the right atrium and the right ventricle __ SA nodeD.In the lateral walls of ventricles __ Bundle of HisE.Natural pacemaker __ Purkinje fibersF.Between the left atrium and the left ventricle D A E B F C ANSWER:

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Blood Vessels Closed pathway that carries blood from the heart to cells and back to the heart Types –Arteries –Arterioles –Veins –Venules –Capillaries

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Arteries and Arterioles Strongest of the blood vessels Carry blood away from the heart Under high pressure –Vasoconstriction –Vasodilation Arterioles –Small branches of arteries Aorta –Takes blood from the heart to the body Coronary arteries –Supply blood to heart muscle

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Veins and Venules Blood under no pressure in veins –Does not move very easily –Skeletal muscle contractions help move blood –Sympathetic nervous system also influences pressure Valves prevent backflow Venules –Small vessels formed when capillaries merge Superior and inferior vena cava –Largest veins –Carry blood into right atrium

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Capillaries Branches of arterioles Smallest type of blood vessel Connect arterioles to venules Only about one cell layer thick Oxygen and nutrients can pass out of a capillary into a body cell Carbon dioxide and other waste products pass out of a body cell into a capillary

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Apply Your Knowledge How do arteries control blood pressure? ANSWER: The muscular walls of arteries can constrict to increase blood pressure or dilate to decrease blood pressure.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Blood Pressure Force blood exerts on the inner walls of blood vessels –Highest in arteries –Lowest in veins Systolic pressure –Ventricles contract –Blood pressure in arteries is at its greatest Diastolic pressure –Ventricles relax –Blood pressure in arteries is at its lowest Reported as the systolic number over the diastolic number

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Blood Pressure (cont.) Control is based mainly on the amount of blood pumped out of the heart The amount of blood entering should equal the amount pumped from the heart Starling's law of the heart –Blood entering the left ventricle stretches the wall of the ventricle –The more the wall is stretched The harder it will contract and The more blood it will pump out

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Blood Pressure (cont.) Baroreceptors –Also help regulate blood pressure –Located in the aorta and carotid arteries –High blood pressure in aorta  message to cardiac center in brain  decreases heart rate  lowers blood pressure –Low blood pressure in aorta  message to cardiac center in the brain  increases heart rate  increases blood pressure

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Apply Your Knowledge What is the difference between the systolic pressure and diastolic pressure? ANSWER: Systolic pressure is the result of the contraction of the ventricles increasing the pressure in the arteries. Diastolic pressure is the result of the relaxation of the ventricles lowering the pressure in the arteries. Good Answer!

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Circulation Pulmonary circuit right atrium  right ventricle  pulmonary artery trunk  pulmonary arteries  lungs  pulmonary veins  heart (left atrium) Systemic circuit left atrium  left ventricle  aorta  arteries  arterioles  capillaries  venules  veins  vena cava  heart (right atrium)

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Circulation (cont.) Arterial system –Carries oxygen-rich blood away from the heart –Pulmonary arteries carry oxygen-poor blood –Paired – left and right artery of the same name

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Circulation (cont.) Venous system –Carries oxygen-poor blood toward the heart Except pulmonary veins –Most large veins have the same names as the arteries they are next to  Hepatic portal system Collection of veins carrying blood to the liver Click for Larger View

© 2011 The McGraw-Hill Companies, Inc. All rights reserved

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Apply Your Knowledge ARTERIES: Pulmonary arteries carry oxygen-poor blood. Do pulmonary arteries carry blood with high levels of oxygen or low levels of oxygen?

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Blood A type of connective tissue –Red blood cells (erythrocytes) –White blood cells (leukocytes) –Platelets – cell fragments –Plasma – fluid part of blood Average-sized adult has 4 to 6 liters of blood Amount depends on:  Size of person  Amount of adipose tissue  Concentrations of ions  Females have less than males Average-sized adult has 4 to 6 liters of blood Amount depends on:  Size of person  Amount of adipose tissue  Concentrations of ions  Females have less than males

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Blood Components Hematocrit –The percentage of red blood cells –Normal is about 45% White cells and platelets = 1% Plasma = 55% © Cre8tive StudiosAlamy RF

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Red Blood Cells Erythrocytes Transport oxygen throughout the body Small biconcave-shaped cells Hemoglobin is a pigment in RBCs –Oxyhemoglobin carries oxygen; bright red –Deoxyhemoglobin does not carry oxygen; darker red Carries carbon dioxide, so also called carboxyhemoglobin –Anemia – low RBC count Erythropoietin – regulates production of RBCs

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Red Blood Cells (cont.) © Cre8tive StudiosAlamy RF

© 2011 The McGraw-Hill Companies, Inc. All rights reserved White Blood Cells Granulocytes –Neutrophils (55%) –destroy bacteria, viruses, and toxins in the bloodstream (phagocytes) –Eosinophils (3%) – get rid of parasitic infections such as worm infections –Basophils (1%) – control inflammation and allergic reactions Agranulocytes –Monocytes (8%) – destroy bacteria, viruses, and toxins in blood –Lymphocytes (33%) – provide immunity for the body

© 2011 The McGraw-Hill Companies, Inc. All rights reserved White Blood Cells (cont.) WBC count normally 5000 to 10,000 cells per cubic millimeter of blood –Leukocytosis Elevated WBC count Usually due to infection –Leukopenia Low WBC count Some viral infections and other conditions

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Platelets Fragments of cells found in the bloodstream Also called thrombocytes Important in the clotting process of blood Normal count –130,000 to 360,000 platelets per cubic millimeter of blood

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Plasma Liquid portion of blood composed mostly of water Proteins –Albumins Smallest plasma proteins Pull water in to help maintain blood pressure –Globulins – transport lipids and fat-soluble vitamins –Fibrinogen – needed for blood clotting Nutrients –Amino acids –Glucose –Nucleotides –Lipids from the digestive tract Gases – oxygen, carbon dioxide, and nitrogen Electrolytes Waste products

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Bleeding Control Hemostasis – the control of bleeding Three processes of hemostasis –Blood vessel spasm –Platelet plug formation –Blood coagulation

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Platelet plug formation:

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Blood Types Types are distinguished by antigens and antibodies Agglutination –Clumping of red blood cells –Antigens on surface of RBCs bind to antibodies in plasma

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Blood Types (cont.) Blood TypeAntigen Present Antibody Present Blood That Can Be Received AABA and O BBAB and O AB NoneA, B, AB, and O ONoneA and BO

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Blood Types (cont.) Rh antigen – protein on RBCs Rh-positive –RBCs contain the Rh antigen Rh-negative –RBCs do not contain the Rh antigen Rh-positive blood is given to Rh-negative person –Antibodies form If Rh-negative person receives more Rh-positive blood –Antibodies bind to the donor cells –Agglutination occurs

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Apply Your Knowledge True or False: __ Hematocrit is the percentage of WBCs in the blood. __ Neutrophils destroy bacteria, viruses, and toxins in the bloodstream. __ Platelets are important to the clotting process. __ Albumin is a small plasma protein that pushes water out of the bloodstream. __ Hemostasis is the control of bleeding. __ A person with type AB blood can only receive type AB blood. __ Blood should be matched for Rh factor. pulls water into RBCs receive any type of blood T T F T F T F ANSWER:

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Chest Pain Cardiac –Myocardial infarction –Angina –Pericarditis –Coronary spasm Non-cardiac –Heartburn –Panic attacks –Pleurisy –Costochondritis –Pulmonary embolism –Sore muscles –Broken ribs Take all complaints of chest pain seriously!

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Chest Pain (cont.) Determine cause –Electrocardiogram –Stress tests –Blood tests –Chest x-ray –Nuclear scan –Coronary catheterization –Echocardiogram –Endoscopy

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Diseases and Disorders of the Cardiovascular System DiseaseDescription AnemiaThe blood does not have enough red blood cells or hemoglobin to carry an adequate amount of oxygen to the body’s cells AneurysmA ballooned, weakened arterial wall ArrhythmiasAbnormal heart rhythms CarditisInflammation of the heart EndocarditisInflammation of the innermost lining of the heart, including valves

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Diseases and Disorders of the Cardiovascular System (cont.) DiseaseDescription MyocarditisInflammation of the muscular layer of the heart PericarditisInflammation of the membranes that surround the heart (pericardium) Congestive heart failure Weakening of the heart over time; heart is unable to pump enough blood to meet body’s needs Coronary artery disease (CAD) Atherosclerosis; narrowing of coronary arteries caused by hardening of the fatty plaque deposits within the arteries

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Diseases and Disorders of the Cardiovascular System (cont.) DiseaseDescription HypertensionHigh blood pressure; consistent resting blood pressure equal to or greater than 140/90 mm Hg LeukemiaBone marrow produces a large number of abnormal WBCs MurmursAbnormal heart sounds Myocardial infarction Heart attack; damage to cardiac muscle due to a lack of blood supply

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Diseases and Disorders of the Cardiovascular System (cont.) DiseaseDescription Sickle cell anemia Abnormal hemoglobin causes RBCs to change to a sickle shape; abnormal cells stick in capillaries ThalassemiaInherited form of anemia; defective hemoglobin chain causes, small, pale, and short-lived RBCs Thrombophlebi tis Blood clots and inflammation develop in a vein Varicose veins Twisted, dilated veins

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Apply Your Knowledge ANSWER: Anemia is a condition in which a person does not have enough red blood cells or hemoglobin in the blood to carry an adequate amount of oxygen to body cells. The doctor has told your patient she has anemia. How would you explain this to her? Bravo!

© 2011 The McGraw-Hill Companies, Inc. All rights reserved In Summary 23.1The structures of the heart include the pericardium, epicardium, myocardium, and endocardium. –The chambers of the heart consist of the upper atria and the lower ventricles. –The septums are interatrial, interventricular, and atrioventricular. –The four valves within the heart are tricuspid, bicuspid, pulmonary semilunar valve, and the aortic semilunar valve.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved In Summary (cont.) 23.2 Superior and inferior vena cavae → right atrium → tricuspid valve → right ventricle → pulmonary semilunar valve → pulmonary trunk → right and left pulmonary arteries → the lungs → pulmonary veins → left atrium → bicuspid valve →left ventricle → aortic semilunar valve → aorta → body organs and tissues Heart sounds are described as lubb dubb. Lubb is created when the ventricles contact and the tricuspid and bicuspid valves snap shut. Dubb occurs when the atria contract and the pulmonary and aortic semilunar valves snap shut.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved In Summary (cont.) 23.4 The sinoatrial node generates an impulse to the atrioventricular node. The AV node then sends the impulse to the bundle of His. The bundle splits into the left and right bundle branches and sends the impulse to the Purkinje fibers in the ventricles The arterial system is composed of the aorta, arteries, and arterioles (largest to smallest) bring blood from the heart to the body. The capillaries act as the connectors between the arterioles and venules. From the venules, blood returns to the heart via the veins to the superior and inferior vena cavae.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved In Summary (cont.) 23.6 Blood pressure is the force exerted on the inner wall of blood vessels by blood as it flows through vessels. It is highest in arteries and lowest in veins. Clinically, BP refers to the force of blood within the arteries. Blood pressure is largely controlled by the amount of blood pumped out of the heart, but various other events may also raise and lower BP.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved In Summary (cont.) 23.7 Pulmonary circulation: right atrium→ tricuspid valve → right ventricle→pulmonary semilunar valve → pulmonary trunk→pulmonary arteries→lungs→pulmonary veins→left atrium. Systemic circulation: left atrium→bicuspid valve→left ventricle→aortic semilunar valve → aorta → arteries → arterioles→capillaries→venules→veins→vena cavae→right atrium.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved In Summary (cont.) 23.8 The largest artery in the body is the aorta. Other major arteries include lingual, facial, occipital, maxillary, ophthalmic, axillary, brachial, ulnar, radial, intercostals, lumbar, external iliac, common iliac, femoral, popliteal, and tibial. The largest veins in the body are the superior and inferior vena cavae. Other major veins are jugular, brachiocephalic, axillary, brachial, ulnar, radial, intercostals, azygos, gastric, splenic, mesenteric, hepatic portal, hepatic, iliac, femoral, popliteal, and saphenous.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved In Summary (cont.) 23.9 The components of blood are red blood cells (RBC), white blood cells (WBC), platelets, and plasma Red blood cells carry oxygen and carbon dioxide throughout the body. White blood cells are divided into two types: granulocytes and agranulocytes. Granulocytes include neutrophils, eosinophils, and basophils. Agranulocytes include lymphocytes and monocytes. Platelets are essential in the blood clotting process Plasma contains three major proteins: albumins, globulins, and fibrinogen.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved In Summary (cont.) 23.12Hemostasis is bleeding control. When a blood vessel breaks, the vessel wall spasms and reduces blood loss. Platelets stick to the broken area and to each other, forming a platelet plug. A blood clot occurs when fibrinogen converts to fibrin, which sticks to the damaged area of the blood vessel, creating a meshwork to trap blood cells and platelets, which will remain while tissues repair themselves.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved In Summary (cont.) 23.13Blood types are named for the antigen present on the cell surfaces. The “opposite” letter is the name of the antibody present. Blood type A has antigen A and antibody B; blood type B has antigen B and antibody A; blood type AB has antigens A and B and 0 (zero) antibodies; Blood type O has no antigens present and both A and B antibodies Rh-positive blood contains the Rh antigen on its RBCs. Rh-negative blood carries no such antigen.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved In Summary (cont.) 23.15Due to the antibodies present on different blood types, it is important for blood typing to be done prior to any transfusion. It is equally important to know if a patient’s blood type is positive or negative for the same reason. A negative blood type will “fight” the positive antigen found on a positive blood type. An Rh-negative woman carrying an Rh-positive fetus will develop antibodies against the child’s blood type.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved In Summary (cont.) 23.16Many different types of cardiac and blood diseases are described in this chapter. The signs, symptoms, and treatments are as varied as the diseases themselves. The Pathophysiology section of this chapter outlines the most common of these diseases, their signs and symptoms, as well as the treatments.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Your work is to discover your world and then with all your heart give yourself to it. ~ Buddha End of Chapter 23