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65 Cards in this Set
- Front
- Back
Arteries |
(Elastic and contractile, walls are thick) Carry blood away from heart |
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Arterioles |
Smaller in diameter; important in regulation of blood pressure; delivers blood to capillaries |
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Capillaries |
Microscopic vessels that connect arterioles to venules; permits exchange of gas nutrients and waste between blood and tissues; critical for homeostasis, main site of cardiovascular activity |
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Venules |
Small veins formed from the union of capillaries; they collect capillary blood and leads to veins |
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Veins |
Carry blood to heart |
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Tunica externa (tunica adventitia) |
(Thickest) Elastic and collagen fibers; stabilize and anchor blood vessels in surrounding tissue; top layer of vein |
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Tunica media (middle) |
Collagen fibers, elastic and smooth muscle fibers (external elastic membrane) middle layer of vein |
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Tunica interna (tunica intima - inner) |
Endothelium and basement membrane (internal elastic membrane) thinner than arteries; bottom layer of vein |
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Artery walls are _____ than veins |
Thicker |
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Artery tunica media contains more _____&_____ than veins do |
Smooth muscle and elastic fibers |
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What do artery walls do when they aren't being opposed by blood pressure? |
Recoil |
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Veins contain valves to prevent____? |
Backflow of blood |
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Elastic arteries (conducting arteries) |
Nearest the heart, largest diameter, help propel blood from heart when ventricles are relaxing, helps maintain blood pressure |
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Muscular arteries (distributing arteries) |
Medium-sized arteries, greater vasoconstriction and vasodilation, distribute blood to body, pressure points to reduce bleeding |
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Arteriosclerosis |
Thickening and toughening of arterial walls |
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Focal calcification |
Calcium salts deposited in tunica media, limbs and genital organs |
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Atherosclerosis |
Formation of lipid deposits in tunica media |
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Arteriosclerosis factors |
Lipid levels, cholesterol, smoking, hypertension, high LDL, diabetes, obesity, stress |
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Arteriosclerosis results |
Plaque formation and can lead to blood clots |
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Vasoconstriction |
Deceased blood flow, increased blood pressure |
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Vasodilation |
Increased blood flow, decreased blood pressure |
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What are the 3 types of capillaries |
Continuous, fenestrated, and sinusoid |
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Continuous capillaries |
Endothelium complete, found in all tissues except cartilage and epithelia, permit diffusion of water, small solutes, lipid soluble materials, prevent loss of blood and plasma protein |
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Fenestrated capillaries |
Pore-containing capillaries, allow rapid exchange of water and solute between blood plasma and IF |
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Sinusoid capillaries |
Capillaries with gaps between cells, permits free exchange of large solutes and water between blood and IF |
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Capillary beds |
Interconnected = 1 arteriole connected to dozens of capillaries |
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Capillary exchange |
Movement of substances between blood plasma and interstial fluid |
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Diffusion |
Movement of a substance down its concentration gradient (high to low) |
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Transcytosis |
Substances enter endothelium by endocytosis, move across cell and leave by exocytosis |
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Bulk flow |
Passive process where large numbers of ions, molecules or particles move together in the same direction (high pressure to low pressure) |
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Filtration |
Pressure-driven movement of fluid and solutes from capillaries into interstitial fluid |
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Reabsorbtion |
Pressure-driven movement from interstitial fluid into blood capillaries |
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Venuos valves |
Venous bp is low and can't overcome force of gravity, valves prevent blood backflow in veins, push blood to heart to improve venous return |
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Venous return |
Volume of blood flowing back to the heart |
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Skeletal muscle pump |
Standing/rest proximal valve closet to heart and distal valve are open; blood flows toward heart (leg muscle contraction compresses vein which pushes blood through proximal valve, distal valve closes, after muscle relaxation proximal valve closes and distal vein opens |
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Respiratory pump |
Alternating compression and decompression of veins during respiration |
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What happens if venous vein malfunctions (stretch/weaken)? |
Blood pools in veins and vessel distends |
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2 types of venous valve malfunction |
Varicose veins and hemorrhoids |
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Edema |
Filtration greatly exceeds reabsorbtion |
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Blood flow |
Volume of blood that flows through any tissue in a given period of time |
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Cardiac output (co) |
Co= hr x sv |
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What determines capillary blood flow? |
Pressure (P) and resistance (R) |
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What must the heart do to keep blood flowing? |
Generate pressure to overcome resistance to blood flow in circuits |
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Flow is proportional to___? |
Pressure |
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Flow is inversely proportional to___? |
Resistance |
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Higher blood viscosity from? |
Dehydration or polycythemia |
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Lower blood Viscosity from? |
Anemia or hemorrhage |
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Mabp |
Perfusion pressure in organs |
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Hypotension |
BP is to low |
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What are the 3 major mechanisms for control of bp? |
Autoregulation, neural mechanism, and endocrine mechanism |
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Autoregulation |
Ability of tissue to adjust blood flow to match metabolic needs in localized area |
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Neural mechanism |
Cardiovascular centers found in medulla oblongota |
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Baroreceptor reflex |
Pressure-sensitive sensory receptors in carotid arteries |
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Chemoreceptor reflexes |
Monitor chemical composition of blood |
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Endocrine mechanism |
Hormones that increase bp, provides short term and long term regulation of cardiovascular performance |
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Epinephrine and norepinephrine |
Stimulate cardiac output and peripheral vasoconstriction |
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Epo |
Increase in rbc's leads to increase in bp |
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Antidiuretic hormone (ADH) |
Increase blood volume |
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Angiotension 2 |
Responds to decreased pressure at kidneys |
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Atrial natriuretic peptide (ANP) |
Produced by cardiac muscle cells in right atrium wall in response to excessive stretching during diastole |
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Histamine |
Causes vasodilation of arterioles |
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What is cardiac output at rest? |
5.8liters/min |
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Maximum level of cardiac output during heavy exercise is ____? |
20-25L/min |
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Shock |
Failure of cardiovascular center to deliver enough oxygen and nutrients to meet metabolic needs of cells/tissues |
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In a capillary bed the bands of smooth muscle at the entrance to each capillary is called a |
Precapillary sphincter |