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61 Cards in this Set
- Front
- Back
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What kind of diet can reduce kidney stones and why?
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A diet high in calcium because they will bind oxalate in the intestines and prevent it from being absorbed and forming calcium oxalate stones in the kidney.
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Describe Golijan's epiphany about the heart valves with regard to stenosis and regurgitation.
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Stenosis is trouble with opening and regurgitation is trouble with closing.
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Can you visulaize how small a capillary is?
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Small enough that a RBC has to deform in order to get through it.
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How much time passes between atrial and ventricular contraction>
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.1s
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How well do most people with hepatitis fare?
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Pretty well. There is about a 95% recovery rate.
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Which type of hepatitis is the only kind that isn't sexually transmitted?
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Hepatitis A
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What is the only kind of hepatitis that doesn't have a vaccine?
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Hepatitis C
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What is the kind of hepatitis that can be transmitted from mother to baby?
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HBV
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What kind of hepatitis is most deadly? Prognosis? Prevalance?
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Hepatitis D on top of a Hepatitis E infection, which has a 20% death rate, but is very rare.
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What is the treatment for hepatitis?
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Let the body fight on it's own, but if it needs help then treat with antivirals.
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What is inotropy? What is it determined by?
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How much your ventricles can contract at a given length. This is determined by concentration of intracellular calcium uncovering actin myosin binding sites.
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What is chronotropic?
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something that produces a change in heart rate
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What is dromotropic?
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Something that produces changes in conduction, particularly in the AV node.
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What measurement can you use to estimate inotropy?
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Ejection fraction.
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What are 6 mechanisms by which intracellular calcium is increased?
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1. Leftover calcium from a previous contraction
2. More calcium being pumped out of SR 3. Less calcium being pumped into SR 4. Increased time that the membrane calcium channels are open. 5. More calcium is stored in the SR so more can be released 6. Less calcium leaving the cell (through Na+ driven ion exchange) |
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What three mechanisms (larger scale) are used to increase inotropy in a person?
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1. Increase the heart rate to increase leftover calcium
2. Sympathetic stimulation of B1 through NE 3. Digitalis |
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How does sympathetic stimulation increase inotropy? (2ways)
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1. It will change the Ca channels to cause a larger influx of calcium during the plateau (More Ca from outside)
2. It will phosphorylate the phospholamban pump to increase storage of Ca in the SR (More CA in SR) |
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How does digitalis increase inotropy?
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It will inhibit the Na/K/ATPase of the cell, which will build up Na in the cell and decrease the Na gradient. There will be less force driving the Na (in)/Ca (out) ion exchange and Ca will be retained.
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Mnemonic for digitalis.
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You put your digit on the pulse of the cell, which is the Na/K pump.
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What is the only negative inotropic factor?
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Parasympathetic stimulation
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How does this work?
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It will decrease contraction of the atria by decreasing the calcium influx there during the plateau phase.
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What does autoregulation mean an how is it controlled?
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It means that an organ is capable of regulating it's own blood flow. This is done by some intrinsic reflex involving chemo or mechanoreceptors that will constrict or dilate blood flow to that organ.
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Why will modifying artery diameter increase blood flow?
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Flow = change in pressure/resistance
if you decrease pressure, you will increase flow. |
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How do you increase blood flow to the head when you stand up too fast? (3)
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Increase sympathetic stimulation reflexively when baroreceptors in the aorta and carotid arteries sense low BP.
1. Increase cardiac output (increase heart rate and ventriculat contractility via B1) 2. Increase resistance to arterioles that are not going to the brain (via a1) 3. Increase venous constriction (via a1) |
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What is the main adrenergic receptor that constricts blood vessels?
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a1
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What is the main adrenergic receptor that dilates blood vessels?
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b2
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What is the main adrenergic receptor that stimulates cardiac output? How does it do this?
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b1
1. Increases heart rate 2. Increases conduction velocity 3. Increases contractility/inotropism |
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In the SA node, what ion brings the cells to threshhold?
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A slow influx of sodium
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What does this mean for the mechanism of chronotropic regulation?
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Sympathetic stimulation can increase heart rate by increasing the inward Na depolarization current in phase 4.
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What causes the action potential upstroke for both the AV and SA node?
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influx of calcium
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In terms of orthostatic hypotension, explain the frank-starling law.
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When the sympathetic stimulation increases venous return, there is increased cardiac output.
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What voluntary thing can you do to recover from a head rsh?
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walk around so that you contract your muscles and increase venous return.
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What is the main control of getting more blood to the heart and skeletal muscle during exercise?
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local mediators
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Is there more or less PVR during exercise? Why?
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Less because local vasodilators contribute more than sympathetic vasoconstriction.
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Is increased heart rate or stroke volume more responsible for increased cardiac output in exercise? How much more?
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Heart rate by almost twice the effectiveness.
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What happens to the blood vessels in the skin during early exercise? Why is this useful?
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Sympathetic stimulation constricts them because they want to shunt all the blood to the muscles and brain.
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What happens to the blood vessels in the skin late in exercise?
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They dilate because the increased body temperature feeds back to the brain and causes selective inhibition of sympathetic neurons going to the skin. The vessels then dilate and release heat.
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What is Hering's nerve? What does it do in response to stimulation?
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It is the carotid sinus nerve that increases firing rate in response to increased baroreceptor stimulation.
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What does increased stimulation of the carotid and aortic baroreceptors do?
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increases parasympathetic action and inversely decreases sympathetic action.
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Does the aortic baroreceptors respond to increased or decreased blood pressure? Why?
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Only increased because the aorta has so much cartilage that it doesn't really collapse under low pressure. (doesn't make sense, but roll with it)
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What are the major systems responsible for long term vs short term regulation of BP?
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Short- autonomic response to baroreceptors
Long- hormonal response to baroreceptors (RAAS system) |
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What are some other, less normally influential regulators of BP.
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ANP and ADH
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What factors into Reynold's number for predicting turbulence of blood? What increases and decreses it?
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Increases: diameter of vessel (more room to bounce around), velocity (more friction per seconD), and density of blood.
Decreases: viscosity |
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Why does turbulence increase in a stenosis?
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diameter may decrease to decrease turbulence, but velocity would then increase by a squared amount to make it an overall increase.
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Where does the blood from hemorrhages usually come from and why?
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The veins because the most blood is pooled there and they get distended and have weaker walls than arteries.
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How can a hemorrhage directly lead to decreased cardiac outsup?
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Less venus return = less CO by the frank-startling mechanism.
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Where is central venous pressure measured and what is the normal value?
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It is measured at the vena cava and is normally 2mmHg.
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how is pulmonary wedge pressure measured and what is it usually?
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it is measured by sticking a catheter through the pulonary artery until the point that it gets wedged and stuck. This is usually right before the capillaries and is 5mmHg.
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What are central venous pressure and pulmonary wedge pressure equal to respectively?
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Right atrial pressure and left atrial pressure.
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what is hematocrit a measure of?
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The % of the blood that is RBC's vs plasma.
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Why would hemorrhage cause decreased hematocrit?
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At first it wouldn't, but as your body compensates for volume loss by increasing aldosterone mediated resorption from the kidneys, you would decrease the RBC to plasma ratio.
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How long does it take for a bone marrow stem cell to become a mature RBC?
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7 days
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Why does giving saline help someone with hypoolemic shock even though it doesn't increase hematocrit?
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It increases enous return, which increases cardiac output and overall blood flow.
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Why would you want to check the urine production of someone that just got treated for hypovolemic shock?
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You can't trust the number on the BP because they may be compensating. If they are producing urine, that means that their kidneys are not vasoconstricted and aldosterone is not resorbing water.
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Why would you be worried about someone with hypotension who is on aspirin?
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When you compensate, you constrict blood vessels including ones to the kidneys. Normally both sympathetic stimulation and aldosterone produce an oppositional release of vasodilating PGE2 and PGI2, but aspirin will inhibit the COX enzyme that does this. You would worry about kidney damage from ischemia in this case.
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What does splanchnic mean?
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visceral organ including the abdominal and pelvic contents.
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How do low doses of dopamine help someone with hypovolemic shock?
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Low doses of dopamine selectively dilate arterioles in critical organs (i.e., heart,
brain, kidney) and selectively constrict arterioles in less critical organs (e.g., skeletal muscle, skin), thus redirecting blood flow where it is most needed. |
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How does dopamine differ from it's relative NE in action?
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It acts directly on the vessels rather than through nerves and will selectively dilate important organs while constricting skin and muscle whereas NE will constrict all of those via a1 and then wait for local vasodilators to be selective about it.
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How does your body adapt to exercise? (2 ways)
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Increase cardiac output and increase the proportion of blood going to the skeletal muscle and skin.
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How does you body know that it needs to start sympathetic stimulation to adapt to exercise? (hint:not BP)
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There are chemo and mechanoreceptors that are in the muscle that relay the info to the motor cortex. This part of the brain then sends the signal to start sympathetic stimulation.
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Is there an overall increase or decrease in BP during exercise?
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an increase in pulse pressure and systolic, but a decrease in diastolic because you are lowering resistance and
P = Q x R without change in Q |
