Chapter 12 The Circulatory System Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Welcome to Unit 2 Project Reminder Slide 2 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 3 HEART Location, size, and position Triangular organ located in mediastinum with two thirds of the mass to the left of the body midline and one third to the right; the apex on the diaphragm; shape and size of a closed fist (Figure 12-1) Cardiopulmonary resuscitation (CPR)the heart lies between the sternum in front and the bodies of the thoracic vertebrae behind; rhythmic compression of the heart between the sternum and vertebrae can maintain blood flow during cardiac arrest; if combined with artificial respiration procedure, it can be life saving Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 4 1 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 5 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 6 HEART Anatomy Heart chambers (Figure 12-2) Two upper chambers called atria (receiving chambers) right and left atria Two upper chambers called atria (receiving chambers) right and left atria Two lower chambers called ventricles (discharging chambers)right and left ventricles Two lower chambers called ventricles (discharging chambers)right and left ventricles Covering sac, or pericardium Pericardium is a two-layered fibrous sac with a lubricated space between the two layers Pericardium is a two-layered fibrous sac with a lubricated space between the two layers Inner layer called visceral pericardium or epicardium Inner layer called visceral pericardium or epicardium Outer layer called parietal pericardium Outer layer called parietal pericardium Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. What is the cardiac muscle tissue called? Each chamber is lined by a thin layer of tissue called __________? What is inflammation of that lining referred to? Slide 7 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Wall of each heart chamber is composed of cardiac muscle tissue called myocardium Wall of each heart chamber is composed of cardiac muscle tissue called myocardium Endocardiumsmooth lining of heart chambersinflammation of endocardium called endocarditis Endocardiumsmooth lining of heart chambersinflammation of endocardium called endocarditis Slide 8 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 9 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. What is contraction of the heart called? What is relaxation called? Slide 10 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Heart action Contraction of the heart is called systole Contraction of the heart is called systole Relaxation is called diastole Relaxation is called diastole Slide 11 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 12 HEART Anatomy Heart valves (Figure 12-3) Valves keep blood flowing through the heart and prevent backflow Valves keep blood flowing through the heart and prevent backflow Consist of two atrioventricular, or AV, and two semilunar (SL) valves Consist of two atrioventricular, or AV, and two semilunar (SL) valves Tricuspidat the opening of the right atrium into the ventricle Bicuspid (mitral)at the opening of the left atrium into the ventricle Pulmonary semilunarat the beginning of the pulmonary artery Aortic semilunarat the beginning of the aorta Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 13 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. What are the two heart sounds? Slide 14 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 15 HEART Heart sounds Two distinct heart sounds in every heartbeat or cyclelub-dub First sound (lub) is caused by the vibration and closure of AV valves during contraction of the ventricles Second sound (dub) is caused by the closure of the semilunar valves during relaxation of the ventricles Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 16 HEART Blood flow through the heart (Figure 12-4) The heart acts as two separate pumpsthe right atrium and ventricle performing different functions from the left atrium and ventricle Sequence of blood flow: venous blood enters the right atrium through the superior and inferior venae cavae passes from the right atrium through the tricuspid valve to the right ventricle; from the right ventricle it passes through the pulmonary semilunar valve to the pulmonary artery to the lungsblood moves from the lungs to the left atrium, passing through the bicuspid (mitral) valve to the left ventricle; blood in the left ventricle is pumped through the aortic semilunar valve into the aorta and is distributed to the body as a whole Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 17 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 18 HEART Blood supply to the heart muscle Blood, which supplies oxygen and nutrients to the myocardium of the heart, flows through the right and left coronary arteries (Figure 12-5); called coronary circulation Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 19 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. What is a heart attack called? What causes a heart attack? What is the term used to describe the chest pain? Slide 20 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Blockage of blood flow through the coronary arteries is called myocardial infarction (heart attack) Angina pectorischest pain caused by inadequate oxygen to the heart Coronary bypass surgeryveins from other parts of the body are used to bypass blockages in coronary arteries (Figure 12-6) Slide 21 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 22 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 23 HEART Cardiac cycle Heartbeat is regular and rhythmiceach complete beat is called a cardiac cycleaverage is about 72 beats per minute Each cycle, about 0.8 seconds long, is subdivided into systole (contraction phase) and diastole (relaxation phase) Stroke volumevolume of blood ejected from one ventricle with each beat Cardiac outputamount of blood that one ventricle can pump each minute; average is about 5 L per minute at rest Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 24 HEART Conduction system of the heart (Figure 12-7) Intercalated disks are electrical connectors that join all the cardiac muscle fibers in a region together so that they receive their impulse, and thus contract, at about the same time SA (sinoatrial) node, the pacemakerlocated in the wall of the right atrium near the opening of the superior vena cava AV (atrioventricular) nodelocated in the right atrium along the lower part of the interatrial septum AV bundle (bundle of His)located in the septum of the ventricle Purkinje fiberslocated in the walls of the ventricles Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 25 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 26 HEART Electrocardiogram (Figure 12-8) Specialized conduction system structures generate and transmit the electrical impulses that result in contraction of the heart These tiny electrical impulses can be picked up on the surface of the body and transformed into visible tracings by a machine called an electrocardiograph The visible tracing of these electrical signals is called an electrocardiogram, or ECG The normal ECG has three deflections or waves P waveassociated with depolarization of the atria P waveassociated with depolarization of the atria QRS complexassociated with depolarization of the ventricles QRS complexassociated with depolarization of the ventricles T waveassociated with repolarization of the ventricles T waveassociated with repolarization of the ventricles Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 27 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 28 BLOOD VESSELS Types Arteries Veins Capillariescarry blood from the arterioles to the venules Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 29 BLOOD VESSELS Types Arteriescarry blood away from the heart Veinscarry blood toward the heart Capillariescarry blood from the arterioles to the venules Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 30 BLOOD VESSELS Structure (Figure 12-9) Arteries Tunica intimainner layer of endothelial cells Tunica intimainner layer of endothelial cells Tunica mediasmooth muscle with some elastic tissue, thick in arteries; important in blood pressure regulation Tunica mediasmooth muscle with some elastic tissue, thick in arteries; important in blood pressure regulation Tunica externathin layer of fibrous elastic connective tissue Tunica externathin layer of fibrous elastic connective tissue Capillariesmicroscopic vessels with only one layer tunica intima Veins Tunica intimainner layer; valves prevent retrograde movement of blood Tunica intimainner layer; valves prevent retrograde movement of blood Tunica mediasmooth muscle; thin in veins Tunica mediasmooth muscle; thin in veins Tunica externaheavy layer of fibrous connective tissue in many veins Tunica externaheavy layer of fibrous connective tissue in many veins Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 31 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 32 BLOOD VESSELS Functions Arteriesdistribution of nutrients, gases, etc., with movement of blood under high pressure; assist in maintaining the arterial blood pressure Capillariesserve as exchange vessels for nutrients, wastes, and fluids Veinscollect blood for return to the heart; low pressure vessels Names of main arteriessee Figure and Table 12-1 Names of main veinssee Figures and and Table 12-2 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 33 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 34 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 35 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 36 CIRCULATION Systemic and pulmonary circulationrefers to the blood flow through the vessels arranged to form a circuit or circular pattern (Figure 12-13) Systemic circulation Carries blood throughout the body Carries blood throughout the body Path goes from left ventricle through aorta, smaller arteries, arterioles, capillaries, venules, venae cavae, to right atrium Path goes from left ventricle through aorta, smaller arteries, arterioles, capillaries, venules, venae cavae, to right atrium Pulmonary circulation Carries blood to and from the lungs; arteries deliver deoxygenated blood to the lungs for gas exchange Carries blood to and from the lungs; arteries deliver deoxygenated blood to the lungs for gas exchange Path goes from right ventricle through pulmonary arteries, lungs, pulmonary veins, to left atrium Path goes from right ventricle through pulmonary arteries, lungs, pulmonary veins, to left atrium Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 37 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 38 CIRCULATION Hepatic portal circulation (Figure 12-14) Unique blood route through the liver Vein (hepatic portal vein) exists between two capillary beds Assists with homeostasis of blood glucose levels Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 39 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 40 CIRCULATION Fetal circulation (Figure 12-15) Refers to circulation before birth Modifications required for fetus to efficiently secure oxygen and nutrients from the maternal blood Unique structures include the placenta, umbilical arteries and vein, ductus venosus, ductus arteriosus, and foramen ovale Have you ever heard of a baby being born with a hole in his heart? Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 41 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 42 BLOOD PRESSURE Defining blood pressurepush, or force, of blood in the blood vessels Highest in arteries, lowest in veins (Figure ) Blood pressure gradient causes blood to circulateliquids can flow only from the area where pressure is higher to where it is lower Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 43 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 44 BLOOD PRESSURE Factors that influence blood pressure (Figure 12-17) Blood volume Strength of contractions Blood viscosity Resistance to blood flow Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 45 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 46 BLOOD PRESSURE Fluctuations in blood pressure Blood pressure varies within normal range Normal average arterial blood pressure is 120/80 Venous blood pressure within right atrium called central venous pressure Venous return of blood to the heart depends on five mechanismsa strongly beating heart, adequate arterial blood pressure, valves in the veins, pumping action of skeletal muscles as they contract, and changing pressures in the chest cavity caused by breathing Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 47 PULSE Definitionalternate expansion and recoil of the blood vessel wall Nine major "pulse points" named after arteries over which they are felt (Figure 12-18) Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 48 Elsevier items and derived items 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Questions? Slide 49