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10 Cards in this Set
- Front
- Back
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How is cardiac output defined?
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Cardiac Output = Heart Rate x Stroke Volume
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What is stroke volume?
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Stroke volume = amount of blood pumped by each ventricle with each heartbeat (average 70 ml, not necessary to know)
CO average ~ 5.25 L, not necessary to know |
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How does exercise alter cardiac output?
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Exercise = increased venous return due to muscular pumping; stroke volume goes up, greater overall throughput
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Name 3 factors that increase cardiac output
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Stress - Pulse and stroke volume up
Exercise - Pulse and stroke volume up Muscle movement - stroke volume up |
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How does a blood pressure cuff work?
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BPC - arteries closed due to greater pressure from cuff; when released, sound is blood squirting through the cuff as pressure exceeds cuff pressure, as released further, no sounds since pressure from cuff never exceeds
first sound is heard, at systolic pressure when sound stops, at diastolic pressure |
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How is blood pressure affected by physical factors?
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BP affected by
vasomotor fiber - constricts blood vessel via norepinephrine release - pressure increases Epinephrine - blood vessel constricts (Fight or flight/sympathetic system) Hematocrit - if EPO is up, number of cells up, blood thicker, BP goes up - if EPO is down, number of cells down, blood thinner, BP goes down Increased fatty tissue - Blood vessel length increases, blood pressure goes up due to resistance Vessel elasticity decreases (arteriosclerosis), BP goes up due to calcified and rigid arteries not being able to expand Increased heat (Sweating) - water leaves blood plasma due to sweating, blood volume goes down, BP goes down over the short term. Eat salty food, increases blood volume, increased water retention, increases BP over the short term due to increased volume |
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Name 4 factors that increase blood pressure
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Vasoconstriction - small arteries
Increased RBCs (through EPO), Increased viscocity Body Fat - more plumbing Increased salt - increased volume of plasma |
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How is rising blood pressure regulated over the short term?
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Rising blood pressure - causes stretching of arterial walls
stimulation of baroreceptors in carotid sinus, aortic arch, and other large arteries of neck and thorax increased impulses to brain increased activity of vagus (parasympathetic system) decreased activity of sympathetic cardiac nerves reduction of heart rate lower cardiac output lower blood pressure |
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Summarize the short term regulation of blood pressure by the body
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Short term response (minutes, nerve response):
if BP is too high Brain increases parasympathetic response, decrease sympathetic, heart should slow if BP is too low Brain increased sympathetic, decreases parasympathetic, heart should speed up |
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Summarize the long term regulation of blood pressure by the body
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Long term response (hours, days, etc - background level):
hormone based Kidneys do long term regulation (Juxtaglomerular cells) If BP remains low, release renin into bloodstream binds to angiotensinogen, converts into angiotensin I at lungs, an enzyme (angiotensin converting enzyme) converts to angiotensin II Angiotensin II stimulates Adenal Cortex to make aldosterone, increase sodium retention, increase water retention, more volume in blood plasma, BP goes up Known as renin-angiotension system/cascade if high pressure is maintained, renin goes down, aldosterone goes down, blood volume goes down |
