Chapter 32: Circulation & Cardiovascular System

Human Heart: Values Values open & close to control blood flow through heart Atriventicular values Tricuspid……. Right Bicuspid………Left Semilunar Values Pulmonary Aortic Blood returning to heart from systemic circuit Enters right atrium Right atrium pumps through tricuspid value to right ventricle Right ventricle pump blood through pulmonary value to the pulmonary circuit Blood returning to heart from pulmonary circuit Enters left atrium Left atrium pumps though mitral value to left ventricle Left ventricle pumps blood through aortic value to the systemic circuit Oxygen poor blood never mixes with oxygen rich blood in humans Heartbeat Systole: Contraction of the heart chambers Diastole: Relaxation of heart chamber Pulse: Two-part pumping action that takes about a second Blood collect in atria, the atria contacts pushes blood through tricuspid & mitral values into the resting lower ventricles This phase (the longer of the two) is called diastolic Second part begins when ventricles fill Ventricles contract This is called systole After blood moves into the pulmonary artery & aorta the ventricles relax Stages in the Cardiac Cycle SA Nodes (Sinoatrial Nodes): keeps the heartbeat regular AV Nodes (Artioventricular node): signals ventricles to contract- Purkinje Fibers ECG (Electrocardiogram) : A recording of electrical changes that occurring in myocardium during cardiac cycle Branches of Ventricular Bundle: Parking Fibers: Ventricular Fibrillation: Rhymetic Contraction due to cardiac conduction system When SA node triggers an impulse the atrial fibers produce an electrical charge (p Wave) Human Cardiovascular System includes two major circular pathways: Takes oxygen poor blood to the lungs The beat of the heart supplies pressure that keeps blood moving in the arteries Systolic Pressure: result from blood forces into the arteries during ventricular systole Diastolic Pressure: is the pressure in the arties during ventricular diastole Skeletal muscle contraction pushes blood in the vein toward the heart Blood Pressure Normally measured with a sphygmomanometer on the brachial artery Expressed in form of systolic & diastolic Hypertension: High Blood Pressure Atherosclerosis: Accumulation of fatty material in inner lining of arties Stroke: Cranial arteriole bursts or is blocked by ab embolus Heart Attack: (Myocardial Infarction) coronary artery becomes partially blocked Angina Pectoris: Painful squeezing Transprt substances to and from capillaries for exchange with tissue fluid Guard against pathogen invasion regulated body temp Buffers body PH Maintains osmatic pressure Clots prevent blood loss Red Blood Cells Small, Biconcave disk Lack a nucleus & contains hemoglobin Hemoglobin contains 4 globin protein chains Each associated with an iron containing heme Manufactured continuously in bone marrow of skull, ribs, vertebrae & end of long bone Carry oxygen, nutrients, and waste White Blood Cells Most types larger than red blood cells Contain nucleus and lack hemoglobin Lymphocytes protect cells from infection WBC: Leukocytes RBC: Erythrocytes) Platelets Involved in coagulation Blood Clots consists of : Platelets Red Blood Cells Red Blood Cells Fiber Capillaries very narrow- Tiny RBC’s must go through single file Wall of capillaries are very thin to facilitate diffusion of nutrients, gases & waste Oxygen & nutrients exit a capillary near the atrial end Carbon Dioxide & waste molecules enter a capillary near the venous end Determined by the presence or absence of surface antigens (agglutinogens) Antigen A,B,& Rh(D) Antibodies in the plasma