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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 CO 2 and O 2
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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
Heart structure • Atrium • Small chambers • Receive blood • Ventricles • Larger chambers • Pump blood from heart • Septum • Separates chambers
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)
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
Blood flow E:\Chapter_42\A_PowerPoint_Lectures\42_Lecture_Presentation\42_06PathOfBloodFlow_A.html
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 • Cardiac cycle: • One cycle of heart filling & emptying • Diastole • Heart resting • Heart filling with blood • AV valves open • Semilunar valves closed
Blood flow • Systole • Ventricles contracting • Pumping blood out of the heart • AV valves closed • Semilunar valves open
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
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
EKG • Electrocardiogram • Records electrical impulses of the heart • P-wave • First wave-atrium contraction • QRS-wave • Ventricles contracting • T-wave • Heart re-polarization
Vessels • Arteries, arterioles • Veins, venules • Capillaries • arteries⇨arterioles⇨capillaries⇨venules⇨veins
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