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Pressure in arteries added by heart contraction o

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pressure in arteries added by heart contractionoEquals the difference between systolic and diastolic blood pressureoE.g., pulse pressure = 40 mm Hg if blood pressure is 120/80, 12
oIt reflects the elasticity and recoil of arteriesThese tend to decline with age and diseaseoPulse pressure allows for palpation of a throbbing pulse in elastic and muscular arteriesClinical View: Detecting a Pulse PointPulse, throbbing of arterial wall Allows determination of heartbeatMore forceful pulse associated with higher pressureAbsence indicates flow to body part lackingPulse pointsWhere artery may be compressed against solid structureE.g., radial, common carotid, femoral, dorsalis pedis, and othersCommon Pulse Points Superficial temporal arteryFacial arteryCommon carotid artery Brachail artery Radial artery (near thumb)Femoral artery (inferior to groin area)Popliteal artery (knee area)Posterior tibial artery (heel of foot)Dorsalis pedis artery (top of foot)Mean arterial pressure (MAP): average arterial blood pressure across entire cardiac cycleoSince diastole lasts longer than systole, the mean is weighted to be closer to diastolic pressureoMAP = diastolic pressure + 1/3 pulse pressureoE.g., if blood pressure is 120/80MAP = 80 + 40/3 = 93oProvides index of perfusion (how well the body’s organs & tissues are perfusedE.g., MAP < 60 may indicate insufficient blood flowMAP of 70 to 110 mm Hg typically indicates good perfusion13
Very high MAP (>150 mm Hg) could indicate the delivery of too large of blood flow to bodyoCerebral edemaCapillary blood pressurePressure no longer fluctuates between systolic and diastolicoFlow and pressure are smoothNeeds to be high enough for exchange of substancesNeeds to be low enough not to damage vesselsArterial end of capillary at about 40 mm HgVenous end of capillary is below 20 mm Hg Accounts for filtration and reabsorption at respective endsClinical View: Cerebral EdemaExcess interstitial fluid in the brainCan occur if MAP greater than 160 mm HgIncreases filtration in brain capillariesNo lymph vessels hereAccumulation of excess fluidVenous blood pressureVenous return of blood to the heart depends on pressure gradient, skeletal muscle pump, and respiratory pumpVenous pressure is low and not pulsatilePressure gradient is smalloBp is 20 mm Hg in venules, almost 0 in vena cavaSkeletal muscle pump assists venous return from limbsoAs muscle contracts, veins are squeezed oBlood is pushed and valves prevent backflowoBlood is moved more quickly during exerciseoBlood pools in leg veins with prolonged inactivity14
Respiratory pump assists venous return in the thoraxBoth inspiration and expiration cause pressure gradient changes that helpoIn inspiration: diaphragm contracts, so abdominal pressure increases and thoracic pressure decreasesBlood in abdominal veins is driven toward thoracic cavityo

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Term
Spring
Professor
Jyoti Wagle
Tags
Physiology, Human Anatomy, Arteries of the abdomen, Subclavian artery

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