Endocrine Control of Fluid and Salt Balance Flashcards Preview

Physiology and Neuroscience > Endocrine Control of Fluid and Salt Balance > Flashcards

Flashcards in Endocrine Control of Fluid and Salt Balance Deck (31):
1

what is the total body water content

0.6 x body weight = 42L

2

what is the intracellular fluid content

0.4 x body weight = 28L

3

what is the extracellular fluid content

0.2 x body weight = 14L

4

what does the extracellular fluid subdivides into?

plasma - 1/4 of ECF = 3.5L
interstitial fluid - 3/4 of ECF = 10.5L

5

what does ECF contains

Na+ 145 moles/L
K+ 4
Cl- 105
HCO3- 25

6

approximate value of osmolarity

[Na+ + K+] x2 or 290-295 milliosmoles/L

7

how much fluid do we take in as drinks

1200 ml/day

8

how much fluid do we take in as food

1000ml/day

9

how much water do we get form the catabolism of food

300ml/day

10

how much water do we lose from lungs and skin

700ml/day

11

how much water do we lose from sweat

100ml/day

12

how much water do we loose from faecal loss

200ml/day

13

how much water do we lose form urine

1500ml/day

14

what is hypovolaemia

a decreased volume of circulating blood in the body.

15

which receptors receive the decrease in the volume of circulating blood

baro-receptors, angiotensin II on subfornical area

16

which receptors receive hypertonicity

osmoreceptors

17

where do the signals from the baroreceptors and osmorecpetors go to?

hypothalamus

18

what are the responses produced by the hypothalamus in response to hypertonicity and hypovalaemia

hypertonicity - thirst
hypokalaemia - vasopressin (ADH) release rom posterior pituitary

19

what is the function of retention of sodium ion

to maintain extracellular volume

20

how does an increase in extracellular volume influence renal loss

it enhances renal loss of sodium ion and hence a fall in volume after diuresis

21

how does a decrease in extracellular volume influence the renal uptake of sodium ion

it enhances renal uptake of sodium ion and hence an increase in volume after antidiuresis

22

fall in venous blood volume

1) general sympathetic discharge
2) constriction of the afferent arteriole
3) reduction in renal blood flow
4) reduction in glomerular filtration rate
5) reduction in sodium chloride presented to
distal convoluted tubule
6) conservation of sodium chloride

23

fall in blood pressure in circulation

1) renal sympathetic nerve discharge - direct effect on renin releasing cells in afferent arteriole
2) reduced renal blood flow and glomerular filtration
3) reduced sodium chloride delivery detected by macula dense cells of the distal convoluted tubule
4) increased renin release
5) eventual increase sodium chloride reabsorption as well as reduced loss

24

what converts angiotensinogen from liver secreted into circulation

plasma renin

25

what does Angiotensin I in lungs and kidneys do

converts enzyme ACE in lung and renal endothelium

26

functions of AT1 receptors

1) pressor effect on smooth muscle of arteries
2) acts on subfornical area to stimulate ADH production and thirst
3) actions on zona glomerulosa cells of adrenal cortex to produce aldosterone

27

functions of aldosterone

increase Na+/K+ ATPase activity in distal tubule
increase sodium ion reabsorption

28

what did de Wardener's experiment confirmed?

existence of ANP

29

what was done in the gardener's experiment

1) an inflatable catheter inserted into the renal artery to stimulate reduced blood pressure
2) injection of maximal stimulatory dose of aldosterone

30

what was the aim of de gardener's experiment

intention to maximise sodium resorption in the distal convoluted tubuleq

31

the site of atrial natriuretic peptide action

1) reduces arterial smooth muscle tone - reduces blood pressure
2) inhibits ADH release
3) inhibits renin release
4) reduces sodium ion absorption in distal convoluted tubule leads to natriuresis