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Flashcards in Physiology 6 (easy) Deck (31)
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1
Q

Secretion stimulated by water-deficit and inhibited by water excess

A

ADH

2
Q

Dominant factor controlling thirst and vasopressin secretion

A

Hypothalamic osmoreceptors

(ADH release also affected by activation of left atrial stretch receptors but hypothalamic osmoreceptors = most important)

3
Q

Atrial pressure and ADH release

A

Decreased atrial pressure INCREASES ADH release

4
Q

What happens when stretch receptors are stimulated in the GI tract

A

Causes feed-forward inhibition of ADH

5
Q

Nicotine and ADH?

A

Stimulates ADH release

6
Q

Alcohol and ADH

A

inhibits ADH

7
Q

How is salt imbalance manifested

A

Change in extracellular volume

8
Q

Which organ produces angiotensin converting enzyme?

A

The lung

9
Q

Where is K+ absorbed

A

Normally, ~90% of K+ is reabsorbed in the early regions of the nephron (mainly the proximal tubule)

When aldosterone is absent the rest is reabsorbed in the distal tubule (therefore, no K+ is excreted in the urine)

10
Q

An increase in plasma K+ stimulates what?

A

Stimulates adrenal cortex = aldosterone

Aldosterone stimulates secretion of K+

11
Q

What controls renin release from granular cells in the JGA?

A

Reduced pressure in afferent arteriole
More renin released, more Na+ reabsorbed, blood vol. increased, blood pressure restored.

Macula densa cells sense the amount of NaCl in the distal tubule
If NaCl reduced, more renin released, more Na+ reabsorbed

Increased sympathetic activity as a result of reduced arterial blood pressure
Granular (renin-secreting) cells directly innervated by sympathetic nervous system, causes renin release.

12
Q

Where is ANP stored and when is it released?

A
  • stored in atrial muscle cells
  • released when they are strethced
  • promote excretion of Na+ and diuresis to reduce plasma volume
13
Q

Difference between water and osmotic diuresis

A

Any loss of solute in the urine must be accompanied by water loss (osmotic diuresis), but the reverse is not true; water diuresis is not necessarily accompanied by equivalent solute loss.

14
Q

How is erythropoiesis regulated?

A

If O2 too low:

  • kidney produces erythropoeitein
  • this stimulates stem cells in bone marrow to produce more red blood cells
15
Q

pH of arterial blood

A

7.45

16
Q

pH of venous blood

A

7.35

17
Q

Average pH of blood

A

7.40

18
Q

Acidosis/alkalosis and the CNS

A

Acidosis can lead to depression of the CNS

Alkalosis can lead to over-excitability of the CNS

19
Q

Acidosis/alkalosis and the CNS

A

Acidosis can lead to depression of the CNS

Alkalosis can lead to over-excitability of the CNS

20
Q

H+ is continually added from which 3 sources?

A

1) Carbonic acid formation
2) Acids produces during breakdown of nutrients
2) acids from metabolism

21
Q

Concentration of HCO3 is controlled by which organ?

A

Kidneys

22
Q

Concentration of PCO2 is controlled by which organ?

A

Lungs

23
Q

Where would you find carbonic anhydrase?

A

Erythrocytes and renal tubular cells

24
Q

How much HCO3 is reabsorbed each day?

A

4300 mmol/day

25
Q

What is titratable acid?

A

The amount of H+ excreted as (largely) H2PO4

-you measure how much strong base you need to turn urine pH back to 7.4

26
Q

Maximum amount of titratable acid that can be excreted each day?

A

40 mmol/day

normal TA is 20mmol/day

27
Q

Where does glutamine come from?

A

Comes from the liver - helps form NH3

28
Q

How to calculate reabsorption of HCO3

A

Rate of reabsorption - rate of excretion

29
Q

How much NH4+ secreted each day?

A

40mmol/mol

30
Q

Total H+ secretion and excretion each day?

A

Secretion: 4360
Excretion: 60

(remember most of your H+ is used to make bicarbonate)

31
Q

TA secretion each day

A

20mmol/day