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46 Cards in this Set
- Front
- Back
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compare/contrast the 3 layers found in artery and vein walls |
ARTERY: round & thick wall -intima: rippled with elastic membrane -media: thick muscle cells, elastic fibers, external elastic membrane -externa: collagen and elastic fibers
VEIN: flat & thin wall -intima: smooth with no elastic membrane -media: thin smooth muscle cells & collagen fibers -externa: has collagen, elastic fibers and smooth muscle |
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Define elasticity |
allows arteries to absorb pressure waves that come with a heartbeat |
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Define contractility |
when arteries change diameter because of the sympathetic division |
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Define vasoconstriction |
contraction of arterial smooth muscle cells by the ANS (makes vessel smaller) |
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Define vasodilation |
relaxation of arterial smooth muscle & the lumen is enlarged |
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What are the major characteristics of arteries? |
thick walls, higher blood pressure, elastic, more muscle, small lumen |
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Compare/contrast the three categories of arteries |
ELASTIC: large vessels, many elastic fibers & few muscle cells, also called conducting arteries MUSCULAR: medium-sized, many muscle cells, also called distribution arteries ARTERIOLE: small, no tunica externa & thin media, also called resistance vessels |
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Define aneurysm |
abnormal widening of a portion of an artery due to weakness in the wall of the vessel |
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Define arteriosclerosis |
hardening of the arteries when fat, cholesterol, and other substances build up & form plaque and the lumen is partially or fully blocked by the plaque buildup |
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What's coronary artery disease? |
the narrowing of the small blood vessels that supply oxygen & blood to the heart |
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Describe the structure of a capillary wall |
only consists of tunica intima (endothelium) & lumen. they have no smooth muscle |
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Compare/contrast continuous & fenestrated capillaries |
CONTINUOUS: only allows water & ions through membrane, uninterrupted wall lining with tight junctions (for water/ions to get through) FENESTRATED: allow small molecules & proteins to get through membrane, which is porous with fibrils (to get across) |
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why is the structure important to capillaries? |
the small networks allow to permeate all active tissues throughout the body |
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what's a pre-capillary sphincter & what does it do? |
It's a sphincter that contracts & relaxes alternately to exchange bloodflow through capillary beds. It can keep blood from circulating by closing the capillaries. |
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describe the structure & function of veins and venules |
MEDIUM-SIZED VEINS: externa is very elastic & media is thin with few muscle cells LARGE VEINS: have all 3 layers. externa's thick & media's thin ***medium & large veins function is to convey blood through the body/to other veins*** VENULES: very small veins that collect blood from capillaries & exchange fluids |
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why do veins have valves? |
because they prevent blood from flowing backwards/keep it going in one direction |
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what are varicose veins? |
swollen, twisted veins with an abnormal collection of blood, can sometimes be painful |
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what are hemorrhoids? |
painful, swollen veins in rectum or anal because of increased pressure against the vein |
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how's blood distributed in different vessel types? |
heart, arteries & capillaries: 30-35% of blood volume
venous system: 60-65% (1/3 of that is found in liver, bone marrow & skin) |
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what's the venous reserve? |
storage of blood from the venous system in liver, bone marrow & skin. is about 20% of blood |
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define blood pressure |
the pressure of blood in the vessels |
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define resistance |
the force that opposes blood flow |
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define stroke volume |
the amount of blood pumped out of the heart with each contraction |
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define heart rate |
the speed of heartbeats per minute |
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what are the four factors that influence cardiac output? |
1. heart rate (higher HR=higher CO) 2. stroke volume (higher SV=higher CO) 3. blood pressure 4. resistance |
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which vessels provide the most resistance & why? |
smaller because of vasoconstriction. includes arterioles, capillaries, venules |
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define systolic pressure & diastolic pressure |
SYSTOLIC: peak arterial pressure during ventricular systole DIASTOLIC: minimum arterial pressure during diastole
BP = systolic/diastolic pressure |
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what are some problems involved with hypotension & hypertension |
HYPOTENSION: not as serious & can be normal for some people. can be caused by pregnancy, heart problems, endocrine problems, dehydration, blood loss, infections, etc. HYPERTENSION: stroke, heart attack, heart failure, renal disease, etc. |
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what's hypertension & hypotension? |
HYPERTENSION: abnormally high blood pressure (greater than 140/90) HYPOTENSION: abnormally low blood pressure (lower than 120/80) |
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what's capillary exchange? |
the movement of oxygen, carbon dioxide, nutrients, and waste molecules between plasma & interstitial fluid. |
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compare/contrast filtration and reabsorption |
FILTRATION: driven out of capillaries by hydrostatic pressure. water & small solutes are forced through capillary walls REABSORPTION: result of osmosis, goes back into the capillaries, blood colloid osmosis prevents osmosis caused by proteins that couldn't get in through filtration |
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define edema & give examples of what might cause it |
the swelling of tissues caused by capillaries leaking fluid & it building up. it can be caused by sitting in one position for too long, eating salty food, PMS, pregnancy, and certain medications. |
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what's venous return? |
how much blood arrives back at the right atrium each minute |
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define shock & it's complications |
when the body doesn't receive enough blood flow & can damage multiple organs. *liver damage = proteins for blood clotting stops being released *kidney damage = muscle function declines |
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is blood volume distributed evenly? |
no |
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what's the formula for mean arterial pressure (MAP)? |
MAP = diastolic pressure + 1/3 pulse pressure |
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what are the formulas for net filtration pressure and net hydrostatic pressure? |
NFP = NHP-NOP NHP = (CHP-IHP) - (BCOP-ICOP) |
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what are the three components of measuring pressure? |
1. blood pressure (BP) - arterial pressure 2. capillary hydrostatic pressure (CHP) - pressure in capillary beds 3. venous pressure - pressure in venous system
**combo of all three = total peripheral resistance** |
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what are the two factors involved with venous return's low pressure? |
pressure gradient=low effective pressure
1. skeletal muscle compression: skeletal muscle pushes blood toward the heart with one-way valve 2. respiratory pump: in thoracic cavity, inhaling decreases pressure & exhaling raises pressure |
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describe capillary exchange with filtration & reabsorption |
filtration delivers nutrients, etc. from atriole and has higher CHP (capillary hydrostatic pressure) & lower BCOP (blood colloid osmotic pressure)
reabsorption takes back some water & toxic materials back into capillary venule. both BCOP and CHP are lower. |
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how do autoregulation, neural, and endocrine mechanisms work? |
AUTOREGULATION: immediate, localized homeostatic adjustments NEURAL: respond quickly to changes at specific sites ENDOCRINE: direct, long-term homeostatic changes |
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what are the two neural mechanisms and what do they do? |
1. baroreceptors: respond to changes in blood pressure 2. chemoreceptors: respond to changes in chemical composition (pH, CO2, O2) |
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what are the two cardiovascular centers, where are they located, and what do they cause? |
1. cardiac centers: contains cardioaccelatory center (higher CO, lower HR) & cardioinhibitory center (lower CO, higher HR) 2. vasomotor center: causes either vasodilation (by parasympathetic) or vasoconstriction (by sympathetic)
**both are found in the medulla oblongata |
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what are the four endocrine mechanisms? describe each |
1. antidiuretic hormone: responds to low blood volume, high osmotic concentration. it elevates BP & reduces water loss in kidneys & the circulating *it elevates BP & reduces water loss in kidneys & the circulating antiogensin II. 2. antiogensin II: responds to fall in renal CP (retaining water). increases BP and stimulates aldosterone & ADH production, thirst, CO & peripheral vasoconstriction (elevated BP) *increases BP and stimulates aldosterone & ADH production, thirst, CO & peripheral vasoconstriction (elevated BP) 3. erythropoietin (EPO): released at kidneys, repsonds to low BP & low O2 in the blood. --*stimulates RBC production. 4. natriuretic peptides: respond to excessive diastolic stretching *lowers BP & BV, reduces stress on heart |
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what are the two types of natriuretic peptides and where are each produced? |
atrial natriuretic peptide (ANP) - right atrium
brain natriuretic peptide (BNP) - ventricular muscle cells |
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what are the cardiovascular responses to hemorrhaging? |
it reduces capillary hydrostatic pressure (CHP) & net filtration pressure (NFP) and increases reabsorption of interstitial fluid |
