Transcript Document
Circulation & Respiration Chapter 42 Circulatory systems Closed circulatory system Vertebrates Blood Enclosed in blood vessels & heart Lymph Lymph system Interstitial fluid Functions 1. Transportation Substances needed for cellular respiration A. Respiratory – CO2 and O2 B. Nutritive – glucose C. Excretory – Metabolic wastes, ions, water Functions 2. Regulation – Hormones – Temperature regulation (Endotherms) 3. Protection – Clotting • Proteins, platelets – Immune defense • WBC, AB Components of the system Heart Blood vessels Blood Heart 4 chambered Separates systemic & pulmonary blood systems Systemic circulation: Blood flow in the body Pulmonary circulation: Blood flow between the heart & lungs Circulation Circulation Heart structure Atrium Small chambers Receive blood Ventricles Larger chambers Pump blood from heart Septum Separates chambers Septum Heart structure Valves Atrioventricular valves (AV) Between the atrium & ventricles Tricuspid---right Bicuspid or Mitral---left Semilumar valves Exits from the ventricles Aortic valve (L ventricle) Pulmonary valve (R ventricle) Valves Heart structure Heart sounds “lub-dub” -valves closing “lub” closing of the AV valves “dub” closing of the semilunar valves Murmur: Abnormal heart sound Heart structure Superior & inferior vena cava Brings blood to heart from body Pulmonary arteries Blood from right side of heart to lungs Pulmonary veins Returns blood from lungs to heart Aorta Blood goes from the heart to body Heart structure Coronary arteries First branches off the aorta Supply blood to the heart Coronary arteries Circulation Path of Blood Flow Blood flow Vena cava Right atrium Tricuspid valve (AV) Right ventricle Pulmonary valve (semilunar) Pulmonary artery Lungs Blood flow Pulmonary veins Left atrium Mitral valve (AV) Left ventricle Aortic valve (semilunar) Aorta Blood flow Blood flow Cardiac cycle: One cycle of heart filling & emptying Diastole Heart resting Heart filling with blood AV valves open Semilunar valves closed Diastole Blood flow Systole Ventricles contracting Pumping blood out of the heart AV valves closed Semilunar valves open Systole Blood pressure Measurement of pressure of blood in the arteries Systolic measures ventricular contraction Diastolic measures ventricular resting Sphygmomanometer or BP cuff Brachial artery 120/80 normal Blood pressure Cardiac output Volume of blood pumped by left ventricle to the body per minute 5 liters per minute Depends on heart rate Stroke volume Amount of pumped out per contraction (70 ml) Cardiac output Increases with exercise Increased HR Better stroke volume Blood pressure Cardiac output Flow resistance in the arteries Affect BP More constriction higher BP More dilation lower BP Baroreceptors Aorta & carotids Medulla oblongata Blood pressure Depends on blood volume Decreased volume Decreased cardiac output Decreased BP Conduction Depolarization of heart muscle stimulates contraction Heart contains autogenic cells Self stimulate SA node (sinoatrial) Pacemaker of the heart Located in R atrium wall Near the superior vena cava Conduction SA node Causes atrium to contract Sends signal to the AV node AV (atrioventricular) node Located in wall between R atrium & ventricle Sends signal to the bundle of His Contraction Bundle of His Sends signal to the Purkinje fibers Ventricles contract SA⇨AV⇨Bundle of His⇨Purkinje fibers Conduction Conduction EKG Electrocardiogram Records electrical impulses of the heart P-wave First wave-atrium contraction QRS-wave Ventricles contracting T-wave Heart re-polarization EKG or ECG Vessels Arteries, arterioles Veins, venules Capillaries arteries⇨arterioles⇨capillaries⇨venules⇨veins Capillaries Blood vessels Vessels Structure (except capillaries) Inner layer is endothelium Next is a layer of elastic fibers Smooth muscle layer Connective tissue Capillaries Endothelium only Arteries Carry oxygen rich blood away from heart Arterioles: Smaller arteries Larger the artery More elastic & recoil as blood is pumped Arteries Vasoconstriction: Contraction of smooth muscle in arterioles Decrease blood flow Vasodilation: Relaxation of smooth muscle Increase blood flow Precapillary sphincters: Regulate blood flow Veins Carry oxygen poor blood to heart Venules Smaller veins Less smooth muscle Skeletal muscles constrict Help flow of blood to heart Venous valves: Help blood flow to heart prevent backflow Capillaries Passage of oxygen & nutrients Into cells or extracellular fluids Passage of carbon dioxide & wastes From cells to blood Blood Blood Plasma (matrix) yellow Metabolites, wastes, hormones Ions Proteins Albumin (fluids), globulins (antibodies), fibrinogen (clots) Cells RBC, WBC, platelets Blood cells Blood formation RBC (erythrocyte) O2 & CO2 transport Hemoglobin (protein) Erythropoietin Hormone (Kidney ) Stimulates RBC production Erythropoiesis RBC production from stem cells Spleen, bone marrow & liver remove RBC Heme Hemoglobin RBC WBC (leukocyte) Larger than RBC Contain a nucleus Fights against infection & FB Interstitial fluid as well as blood Granulocytes: neutrophils, eosinophils, basophils Non-granulocytes: lymphocytes, monocytes WBC Platelets Megakaryocyte (bone marrow) Cell fragments Clotting First to site of injury Fibrin (protein that forms clot) Platelets Clotting Tissue damage Platelets arrive Cascade reactions start Prothrombin changes to Thrombin (enzyme) Changes fibrinogen to fibrin Forms clot Fibrin Blood More RBC than WBC Hematocrit Measurement of RBC’s in the blood RBC last about 120 days Lymph system Interstitial fluid Fluid from blood plasma that leaves the capillaries Surrounds the tissues Lymph: Returns to circulation via lymph system Lymph nodes, lymph vessels & organs (spleen & thymus) Edema Swelling of tissues Usually ankles or feet Interstitial fluid cannot be returned Low protein (albumin) Liver disease Heart disease Pregnancy Varicose veins Too much blood in legs Valves veins do not work MI Flutter Atherosclerosis Aneurysm Infarct Pacemaker VSD MVP