K6 - Control of Body-fluid volume and Osmolarity

Question 1

what does antidiuretic mean?

Answer 1

decrease urinary production and output

Question 2

what is produced by the hypothalamus and stored in the posterior pituitary gland?

Answer 2

ADH

Question 3

what controls the release of ADH from the pituitary into the blood?

Answer 3

hypothalamus

Question 4

what stimulates ADH secretion?

Answer 4

water-deficit (dehydrated)

Question 5

what inhibits ADH Secretion?

Answer 5

water- excess

Question 6

what Effect does ADH have on water permeability of distal tubule and collecting duct

Answer 6

Increases permeability of luminal membrane to H2O by inserting new
water channels

Question 7

what are the symptoms of the diabetes insipidus?

Answer 7

• large volumes of dilute urine

- constant thirst

Question 8

what is the treatment for diabetes insipidus?

Answer 8

ADH replacement

Question 9

What is the most important stimulus for ADH release?

Answer 9

Hypothalamic osmoreceptors

Question 10

what also effects ADH release?

Answer 10

activation of left atrial stretch receptors

Question 11

What does decreased atrial pressure do in terms of ADH release?

Answer 11

increases ADH release

Question 12

what effect does nicotine have on ADH release?

Answer 12

stimulates it

Question 13

What effect does alcohol have on ADH release?

Answer 13

inhibits it

Question 14

What does a increase in osmolarity do to thirst?

Answer 14

increase thirst

Question 15

What does an increase in ADH do to plasma volume?

Answer 15

increase

Question 16

What is important for long term regulation of blood pressure?

Answer 16

Regulation of extracellular fluid volume

Question 17

What is the amount of Na+ filtered regulated by?

Answer 17

regulation of GFR

Question 18

what does Na excreted equal?

Answer 18

Na filtered - Na reabsorbed

Question 19

what regulates the amount of Na reabsorbed?

Answer 19

renin-angiotensin-aldosterone system

Question 20

where is the Steroid hormone secreted by the adrenal cortex?

Answer 20

aldosterone

Question 21

when is aldosterone secreted?

Answer 21

1. In response to rising [K+] or falling [Na+] in the blood

2. activation of the renin-angiotensin system

Question 22

what does aldosterone do?

Answer 22

Stimulates Na+ reabsorption and K+ secretion

Question 23

what % of K+ is reabsorbed in the early regions of the nephron

Answer 23

90%

Question 24

what directly stimulates adrenal cortex?

Answer 24

increase in [K+]plasma

Question 25

in terms of K+ what does aldosterone stimulate?

Answer 25

secretion of K+

Question 26

What does a decrease in plasma [Na+] promote?

Answer 26

promotes the indirect secretion of aldosterone by means of the juxtaglomerular apparatus

Question 27

Explain the control of renin release from the granular cells in JGA?

Answer 27

1. Reduced pressure in afferent arteriole
   - More renin released, more Na+ reabsorbed, blood vol. increased, blood pressure restored.
2. Macula densa cells sense the amount of NaCl in the distal tubule
   - If NaCl reduced, more renin released, more Na+ reabsorbed
3. Increased sympathetic activity as a result of reduced arterial blood pressure
   - Granular (renin-secreting) cells directly innervated by sympathetic nervous system, causes renin release.

Question 28

What part of the kidney is renin released from?

Answer 28

granular cells

Question 29

what do Abnormal increases in R-A-A system cause?

Answer 29

hypertension

Question 30

What do ACE inhibitors do?

Answer 30

stop fluid & salt retention and arteriolar constriction

Question 31

what hormone is produced by the heart and stored in the atrial smooth muscle cells?

Answer 31

Atrial natriuretic peptide (ANP)

Question 32

what causes the release of ANP?

Answer 32

when atrial smooth muscle cells are mechanically stretched due to an increase in the circulating plasma volume

Question 33

how does ANP decrease plasma volume?

Answer 33

ANP promotes excretion of Na+ and diuresis