physio question

[BUSODM]

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if there is excessive constriction of efferent arteriole why would be decreased capillary blood pressure can anybody explain?

 

[BUSODM]

decreased alveolar co2 will allow equal amount of alveolar oxygen what does this mean ,can someone explain?

 

[mg777]

if there is excessive constriction of efferent arteriole why would be decreased capillary blood pressure can anybody explain?

i think this is referring to the nephron.

 

[fightingspirit]

if there is excessive constriction of efferent arteriole why would be decreased capillary blood pressure can anybody explain?

ok, which capillaries are u referring to? the tuft within bowman, or medullary? if there is increased vascular tone in the afferent arteriole, then the renal blood and plasma flow are reduced. however, the hydrostatic pressure within the tuft is not decreased. in fact, it is increased resulting in a higher filtration fraction. on the other hand, the heightened resistance in the afferent arteriole will result in a lower flow AND pressure in the medullary capillaries. i hope this helped a little.

 

[BUSODM]

i was talking about excessive constriction of efferent.

 

[BUSODM]

i think this is referring to the nephron.

those are 2 different questions

 

[fightingspirit]

i was talking about excessive constriction of efferent.

sorry. i dont know why i read Afferent.

for Afferent, increased tone results in decreased renal blood flow. decreased blood flow results in decreased hydrostatic pressure within bowman capillaries; decreased pressure results in decreased GFR.

if there is increased vascular tone in the Efferent arteriole, then the renal blood and plasma flow are reduced. however, the hydrostatic pressure within the tuft is not decreased. in fact, it is increased resulting in a higher filtration fraction. on the other hand, the heightened resistance in the afferent arteriole will result in a lower flow AND pressure in the medullary capillaries.

 

[dentheartthrob]

if there is excessive constriction of efferent arteriole why would be decreased capillary blood pressure can anybody explain?

constriction of the efferent arteriole, increases glomerular capillary hydrostatic pressure, however excessive constriction will devcrease RBF and GFR, and a decreased GFR will result in a decreased BP due to decresed renal perfusion.

 

[BUSODM]

constriction of the efferent arteriole, increases glomerular capillary hydrostatic pressure, however excessive constriction will devcrease RBF and GFR, and a decreased GFR will result in a decreased BP due to decresed renal perfusion.

why will it decrease GFR? can answer me again in detail.thanks

 

[dentheartthrob]

why will it decrease GFR? can answer me again in detail.thanks

my best guess is a negative feed back from the angiotensin system.

 

[BUSODM]

I was talking about excessive constriction.

 

[BUSODM]

my best guess is a negative feed back from the angiotensin system.

I really cant understand what you are trying to say can you please explain .I think angiotensin does not have any effect on efferent arterioles and by the way i am not talking about the causes of excessive efferent constriction but the consequences .

 

[pol37]

I u have a excessive construction on the efferent arteriole - your body tries to counter act it on a wider scale with lowering Renal Blood Flow and lowering GFR. If its only an efferent arteriolar vasoconstriction (not excessive) you will have an increased GFR. By the way Angiotensin II constricts the efferent arteriole

 

[pol37]

My Q:

the partial pressures of respiratory gases found in arterial blood correspond most closely to those partial pressures found in the

1. alveoli (ans)
2. atmosphere
3. tissue fluid
4. venous blood
5. cells throughout the body

should there be not be a difference in pressure, that the gas from the alveoli diffuses to the vessel. I thought that is the concept behind the gas exchange, how can that be the answer. 😕

 

[dentheartthrob]

I really cant understand what you are trying to say can you please explain .I think angiotensin does not have any effect on efferent arterioles and by the way i am not talking about the causes of excessive efferent constriction but the consequences .

Negative feedback: When the system variable returns to the optimal value designated by the set point, negative feedback will alert the correctional mechanism to SHUT OFF.


negative feed back mechanism of the angiotension system, will reduce or stop the amount of renin produce when the the optimimum value is reach or has surpassed the required amount. as we know this system is stimulated when there is low renal BP or p02, or low GFR, and the mechanism to reach equilibrium is done by vasoconstricting the efferent arteriole via AT-II, now excessive constriction of which will stimulate a negative feed back from this system ultimately resulting in lowering the RBF, GFR from beyond the optimum value caused by excessive constriction of the efferent arteriole.

 

[dentheartthrob]

My Q:

the partial pressures of respiratory gases found in arterial blood correspond most closely to those partial pressures found in the

1. alveoli (ans)
2. atmosphere
3. tissue fluid
4. venous blood
5. cells throughout the body

should there be not be a difference in pressure, that the gas from the alveoli diffuses to the vessel. I thought that is the concept behind the gas exchange, how can that be the answer. 😕

I think it has to do something with the dead airspace which reduce the partial pressure slightle from the atm pressure. if im not mistaken its slightle lower by 4 mm/Hg.

 

[BUSODM]

so excess angiotensin cause excess constriction.Thanks for your detailed explanation.

 

[BUSODM]

My Q:

the partial pressures of respiratory gases found in arterial blood correspond most closely to those partial pressures found in the

1. alveoli (ans)
2. atmosphere
3. tissue fluid
4. venous blood
5. cells throughout the body

I can only think of FRV by seeing answer but not sure though

 

[s m i l e 2007]

can anyone tell me why is it arterial pressure of co2 not increased during excercise.
thanks in advance

 

[DREDAY]

can anyone tell me why is it arterial pressure of co2 not increased during excercise.
thanks in advance

most of it gets converted to HCO3 and H, some gets bound by protein portion of hemoglobin.

 

[pol37]

maybe its simpler than I think - the uptake of gases form the alveoli to the arterioles must be trough simple diffusion so the pressure is not equal but very close to make the exchange possible - every diffusion against a gradient is facilitated diffusion - maybe that is the what they ask - not sure but the only thing I can think off. Correct me if you guys disagree.

One more:

which of the following is solely determined by the nernst (equilibrium) potential for sodium between the inside of the axon and the surrounding tissue fluid?

1. the membrane potential
2. the extent of the after-potential
3. the sodium permeability of the nerve
4. the potassium permeability of the nerve
5. the limit of the peak of the action potential (ans)

I don't think that I know what the nernst potential is. I'm just guessing here but even if I knew - I don' t know what they even mean with ans # 5 😕😕😕

 

[tuanng27]

Nerst potential is the potential accross membrane where Na does not move in or out of the cell if the Na channel is open indefinitely without the interfere of second ion like for instance Potassium, Na nerstm potential would be + mv while for potasium it is -90 mv if I am not remember correctly. with the nerstm equation put together with these value you find out that your resting potential. so the peak potential is dictate by the nerst potential of each Ion. so Na Nermst potential dictates the peak action potential while Potassium Nermst potential dictates the lowest action potential will take place.

 

[pol37]

So the nernst potential always gives u the maximum value in Na (highsest point) and K (lowest point) - is that correct? Thank you very much 🙂

 

[DrTacoElf]

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