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Flashcards in Hormonal Regulation of Salts Deck (31)
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1

How do the kidneys keep the ECF volume constant?

They match the excretion of NaCl to the ingested NaCl.

2

What are positive and negative Na balances?

Positive Na Balance - intake > excretion
Negative Na Balance - excretion > intake

3

What does the Na+ balance affect in the ECF?

It affects the volume of the ECF but not the [Na+]

4

How does an increase in Na+ affect the ECF?

It will increase the ECF's volume

5

What is the effective circulating volume (ECV) and how is it different from the ECF?

ECV is the portion of the ECF that is in the circulatory system and is perfusing tissues.

6

What is ECV related to?

Arterial Pressure
Cardiac Output

7

What is the effect of decreased ECF on ECV?

Decreased ECF will lower blood volume, BP or cardiac output and the ECV will decrease.

8

What is the effect of increased ECF on ECV?

It will increase blood volume, BP or cardiac output and the ECV will increase

9

Can the ECF and ECV vary independently?

They can in some diseases such as:

congestive heart failure
hepatic cirrhosis
pleural effusion

10

What happens with a trigger of the atrial stretch receptors?

Atrial Natriuretic Peptide would be released which leads to the increased excretion of Na and water.

11

What happens with pulmonary vascular engorgement?

The sympathetics would become less active and ADH would be decreased leading to diuresis and increased urine output.

12

What happens with increased stimulation of the aortic and carotid baroreceptors?

Sympathetic nerve activity will decrease and ADH will decrease. This leads to increased urine flow and diuresis.

13

What happens when tubular flow becomes very slow?

The juxtaglomerular apparatus is stimulated and renin is increased which leads to increased aldosterone and will increase the reabsorption of water and Na.

14

What happens with increased liver pressure?

Decreased sympathetic activity leading to decreased ADH and increased Na excretion

15

What happens with increased portal vein Na sensors?

Decreased sympathetic activity leading to decreased ADH and increased Na excretion

16

What happens with increased [Na] in the carotid artery and the CSF?

Sympathetic activity will be decreased and Na excretion will increase.

17

What is the effect of increased renal sympathetic nerves?

This occurs as a response to decreased GFR.

Renin secretion will increase which will lead to increased Na reabsorption along the nephron.

18

What is the effect of increased Renin-Angiotensin-Aldosterone activity?

Increases in AT-II will stimulate reabsorption of Na along the nephron and it will stimulate secretion of ADH.

Increases in aldosterone will stimulate Na reabsorption in the thick ascending limb, distal tubule and the collecting duct.

-> Salt Retention

19

What happens with increased ANP secretion?

This occurs as a response to increased GFR.

It will decrease renin secretion and aldosterone secretion. This leads to decreased water and Na reabsorption by the CD and the ADH secretion will be decreased as well.

-> Salt Excretion

20

What happens with increased ADH secretion?

Leads to increased H2O reabsorption in the distal tubule and the collecting duct.

21

What are the 3 factors that are important in renin secretion?

-Perfusion pressure of the afferent arteriole which acts like a baroreceptor

-Sympathetic nerve activity will activate renin secretion

-NaCl delivery to the macula densa via TG feedback where if there is decrease NaCl to the macula densa then the renin secretion will increase

22

What is the negative feedback loop concerning the macula densa?

As ECV decreases, BP will decrease and so sympathetics will increase leading to decreased renal perfusion and decreased GFR to the macula densa which will increase the renin secretion and raise the ECV.

23

What is the pathway of renin?

Renin activates angiotensinogen into AT-I
AT-I -> AT-II in the lung via ACE
AT-II stimulates ADH release and aldosterone production
Aldosterone increases the number of Na-K ATPase pumps which leads to increase Na and H2O reabsorption

24

What is the effect of ANP on sympathetics?

It will decrease sympathetic activity which will decrease ADH and increase GFR.

Decreased ADH will lead to water diuresis.
Increased GFR will lead to increased Na excretion

25

What is the effect of ANP on aldosterone?

It will decrease aldosterone and lead to decreased Na reabsorption

26

What is the effect on ANP on renin?

It will decrease renin and lead to decreased Na reabsorption

27

What is glomerulotubular balance?

In the PT Na reabsorbed load is proportional to the filtered load

28

Describe the reabsorption of Na in the TAL. What is it proportional to?

Na reabsorption in the TAL is proportional to the Na delivery rate

29

What is Na reabsorption in the DT and CD stimulated by?

Increased Na loads

30

What are the 3 main responses to increased ECV?

Increased GFR
Decreased Na reabsorption in the PT
Decreased Na reabsorption in the CD

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