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38 Cards in this Set
- Front
- Back
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Too much water will cause
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hyponatremia
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too little water will cause
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hypernatremia
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too much sodium will cause what pathology?
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edema
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when you have too little sodium you are experiencing?
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volume depletion
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is osmolality regulation controlling water or Na regulation?
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WATER
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is volumeregulation controlling water or Na regulation?
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Na EXCRETION
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regulation of Na+ will affect what?
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Blood volume and thus BP
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decrease in MAP will be sensed by what?
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carotid and aortic baroreceptors will decrease in their firing
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What will the lowered BP sensed by baroreceptors lead to?
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Increased Sympathetic output (to increase peripheral resistance and CO)
Decreased parasympathetics (for increased CO) all lead to increased BP back to normal |
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what is the job of intrarenal baroreceptors
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sense a decrease in renal AFFERENT pressure
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do intrarenal baroreceptors send signals to the brainstem?
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NO, they are not nerve cells, they act on their own, but are subject to SNS tweeking
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Renin producing granular cells have what other function?
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they act as intrarenal baroreceptors
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When you have hemorrhage or any blood loss or lowered pressure, list the order of events of RAAS leading to increased BP
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decreased pressure sensed by intrarenal baroreceptors
signal sent to granular cells they secret renin leads to increase in angiotensin which causes Na uptake at the ENaCl channel in the principle cell, and thus water uptake leading to increased BP |
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What does the macula densa do when it senses decreased NaCl?
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Vasodilates the afferent arteriole
and increases RAAS (which leads to Ang II causing vasoconstriction of efferent) |
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what effect will RAAS have on the efferent arteriole? GFR?
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RAAS (which leads to Ang II causing vasoconstriction of efferent while maintaining GFR
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If you don't have enough volume, what do you want to do to Na and Water?
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reabsorb it
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Na excretion=
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Na filtered - Na reabsorbed
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What 2 variables does Na excretion depend on? of these, which is more regulated?
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GFR (affects teh amount filtered)
Na reabsorbed Na is the major regulated variable |
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What does SNS do to GFR and RBF, and how?
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--constricts both afferent and efferent
--this decreases RBF with only small changes in GFR |
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recall: with high constriction of the efferent arteriole, what controls the rate of GFR?
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decreased RBF
so decreased GFR |
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recall: with slight constriction of the efferent arteriole, what controls the rate of GFR
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increased Pgc
so increased GFR |
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What effect does the RAAS system have on the efferent arterioles?
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constricts them (probably a bit on the afferent too)
net effect: decrease RPF with little or no change in GFR |
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what effect will SNS and RAAS have on the filtration factor
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if SNS and RAAS lead to decreased RBF while relatively maintaining GFR, FF will increase
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What protective mechanism prevents angiotensin II from causing over constriction?
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it causes the synthesis and release of renal prostiglandins
these cause the relaxation of the renal arterioles and mesangial cells |
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How do Ang II and NE lead to increased Na uptake in the proximal tubule?
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they tweak both the Na/H anti porter on the lumenal side and the Na/K ATPase on the basolateral side to increase Na reabsorption
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What does ang II do to vasa recta blood flow? What does this lead to?
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Decreases vasa recta blood flow
leads to decreased washout of urea from medullary interstitum leads to INCREASED UREA AND DECREASED Na in medullary interstitum thus increases the Na gradient for NaCl in the thin ascending limb of Henle thus decreasing Na and H2O excretion |
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12. What type of event is the Pressure natriuresis and diuresis? What does ti do? What is the mechanism behind this??
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a. Intrarenal event, proximal tubule event
a. High pressure you dump lots of Na and Water a. The intrarenal baroreceptors sense and increase in pressure i. Turn down the secretion of angiotensin 1. So you lower the reuptake of Na and dump it with water |
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please describe the RAAS pathway
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angiotensin--(renin)-->Angiotensin I-(ACE)-->Ang II
Ang II projects to: adrenal cortex-->increased aldosterone release-->decreased Na excretion renal proximal tubule--> decrease Na excretion peripheral arterioles--> increase SVR ALL LEAD TO INCREASED BLOOD VOLUME AND ARTERIAL PRESSURE |
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what does high pressure do to Na and water? what is this known as? is this a local or system effect?
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lead to its excretion (isotonic urine)
Pressure Natriuresis and Diuresis Local effect |
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What are the 3 most important effects of Angiotensin?
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1. aldosterone secretion
2. vasoconstriction (increased systemic blood pressure) 3. Na reabsorption (via the Na/H antiporter and Na/K ATPase tweaking) |
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What 2 things activate aldosterone? what inhibits its release?
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Activated by: Ang II, increased K+
Inhibited by: ANP |
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What is glomerulotubular balance?
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nephron excretes a constant fraction; if more is filtered, excreeting a constant fraction will excrete a greater absolute amount, thus promoting dumping of Na
if less is filtered, this means Na excretion is lessened and you conserve Na |
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what does autoregulation do?
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prevents GFR from changing too much in response to changes in BP
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what does ADH do to Na? and where?
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promotes its reabsorption in the TAL and CCD
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what stimulates the release of ADH? 3
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increased plasma osmolality
decreased volume circulating Ang II |
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What activates ANP?
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released from atrial myocytes in response to stretch
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What are teh actions of ANP (3)
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kidney dumps Na+ and water to decrease volume
Inhibits renin, aldosterone, and AVP Vasodilates renal arteries |
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what sensors cause the release of ADH?
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atria and carotid sinus (baro receptors)
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