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Includes transport of: 1. oxygen 2. carbon dioxide 3 nutrients 4. water 5. ions 6. hormones 7. antibodies 8. metabolic wastes Functions of Human Circulatory System Chp. 8
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The Human Circulatory System 4 chambered heart Arteries Capillaries Veins
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Arteries muscular vessels carrying blood away from heart carry oxygenated blood –Exception- pulmonary artery (to lungs)
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Capillaries thin walled (one cell layer) vessels arise from arterioles (tiny arteries) form capillary beds all exchange between blood & cells occurs here
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Veins Venules receive blood from the capillaries Low oxygenated blood transferred to veins Veins carry low O2 blood to heart –Exception- pulmonary vein carries oxygenated blood Thin walled & flattened Nearer to body surface than arteries
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Circulation Through Human Heart Body blood enters RIGHT SIDE of HEART Right atrium ----> right ventricle ----> Pulmonary artery ----> alveoli in lungs----> oxygenated blood --> Pulmonary Veins ----> Left Atrium. ----> Left Ventricle ----> blood leaves through Aorta (first artery) ---> flows to body
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Control of the Heart 1.Extrinsic (outside) 2.Intrinsic (within)
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Extrinsic (outside) control of heart beat autonomic nervous system adrenal hormone epinephrine heart itself can secrete regulatory hormones when changes in blood pressure in the atria are detected.
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Intrinsic (within) control Origin of heart beat –Sinoatrial (SA) node ( pacemaker) May be influenced by autonomic nervous system
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Human Circulatory System Circuits 1.Hepatic Portal Circuit 2.Renal Circuit 3.Cardiac Circuit 4.Systemic Circuit
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Capillaries composed of interlocking cells one cell thick nutrients, ions, water, & oxygen diffuse here Blood moves from capillary to a venule, picks up: ions Water carbon dioxide metabolic wastes nutrients from intestine Materials leave capillaries by three mechanisms: 1. Diffusion 2. Hydrostatic pressure 3. Pinocytosis
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Veins Entering blood volume equals that leaving arteries blood pressure is much lower than in arteries
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Movement through veins assisted by: 1)one way flap-like valves allow blood to move in one direction (toward heart) 2)some smooth muscle around larger veins that contracts and moves blood 3)limb and breathing movements literally massages veins and squeezes blood along
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Arterioles and Capillaries Figure 8.2
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Capillary Structure Figure 8.4
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Function: maintain blood volume; also functions in immune system Structure –Blind-ended capillaries –Lymphatic vessels –Lymph Lymphatic System
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The Heart Figure 8.8
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Structure Layers; epicardium, myocardium, endocardium Chambers: two atrias, two ventricles Valves –Two atrioventricular valves: tricuspid and bicuspid (mitral) –Two semilunar valves: pulmonary and aortic The Heart
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–Deoxygenated blood through the vena cava to the right atrium –Deoxygenated blood through the right atrioventricular valve to the right ventricle –Deoxygenated blood through the pulmonary semilunar valve to the pulmonary trunk and the lungs –Oxygenated blood through the pulmonary veins to the left atrium –Oxygenated blood through the left atrioventricular valve to the left ventricle Pulmonary Circuit: Oxygenation of Blood
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–Oxygenated blood through the aortic semilunar valve to the aorta –Oxygenated blood through branching arteries and arterioles to the tissues –Oxygenated blood through the arterioles to capillaries –Deoxygenated blood from capillaries into venules and veins –Ultimately to the vena cava and into the right atrium Systemic Circuit: Delivery of Oxygenated Blood to Tissues and Return of Blood to the Heart
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Cardiac Cycle Figure 8.12
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Lub-dub Heart murmurs Heart Sounds and Heart Valves
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Cardiac Conduction System Coordinates Contraction SA node: cardiac pacemaker AV node: relay impulse AV bundle and Purkinje fibers: carry impulse to ventricles Figure 8.14
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Three formations –P wave: impulse across atria –QRS complex: spread of impulse down septum, around ventricles in Purkinje fibers –T wave: end of electrical activity in ventricles Arrythmias, ventricular fibrillation Electrocardiograms (EKG/ECG)
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Electrocardiograms (EKG/ECG) (cont.) Figure 8.15B, C
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Definitions: “normal” –Systolic pressure –Diastolic pressure Measurement: sphygmomanometer Blood Pressure
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Hypertension: high blood pressure –Definition –The silent killer –Risk factors Hypertension: blood pressure too low –Clinical signs: dizziness, fainting –Causes: orthostatic, severe burns, blood loss Blood Pressure
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Baroreceptors: pressure receptors in aorta and carotid arteries Steps in mechanism –Blood pressure rises, vessels stretched –Signals sent to brain in the cardiovascular center –Heart signaled to lower heart rate and force of contraction –Arterioles vasodilate, increasing blood flow to tissues –Combined effect lowers blood pressure Regulation of the Cardiovascular System: Baroreceptors
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Medulla oblongata signals –Sympathetic nerves: constrict blood vessels, raising blood pressure –Parasympathetic nerves: dilate blood vessels, lowering blood pressure Hormones: epinephrine (adrenaline) Local requirements dictate local blood flow Regulation of the Cardiovascular System: Nervous and Endocrine Factors
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Angina pectoris: A warning Myocardial infarction/heart attack: permanent cardiac damage Congestive heart failure: decrease in pumping efficiency Embolism: blockage of blood vessels Stroke: impaired blood flow to the brain Cardiovascular Disorders
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Smoking: Don’t Blood lipids: monitor cholesterol levels Exercise: regular and moderate Blood pressure: treat hypertension Weight: being overweight increases risk of heart attack and stroke Control of Diabetes Mellitus: early diagnosis and treatment delays onset of related problems Stress: avoid chronic stress Reducing the Risk of Cardiovascular Disease
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Cardiac Anatomy Quiz Test Yourself, page 172 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
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Blood Connective tissue plasma matrix + 3 types cells Plasma = 90% water + 10% plasma solids. Solids include: urea amino acids glucose hormones ions fats proteins
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The 3 Major Blood Proteins albumins - large proteins that bind impurities & some toxins, aid in transport of hormones, fatty acids and ions, help maintain osmotic balance. globins - include antibodies (immunoglobins) fibrinogen - important in blood clotting
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Blood Cells A)Erythrocytes B)Leukocytes C)Platelets
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Erythrocytes (red blood cells) 1.small, disk-like shape 2.no nucleus 3.cannot reproduce 4.last 4 months then rupture 5.produced by red bone marrow 6.contain hemoglobin 7.carry oxygen
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Leukocytes (white blood cells) Nucleus present Active in immune system most are neutrophils that engulf microorganisms Basophils Eosinophils lymphocytes
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Platelets (thrombocytes) tiny numerous cell fragments aid blood clotting
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Circulatory system + lymphatic system = Proper Osmotic Conditions
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Three Fluid Regions Of Body 1) fluid of blood and lymph 2) interstitial fluid - watery fluid between and among cells 3) intracellular fluid
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