Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

HUBS192 > Lecture 33 physio Body water - distribution and regulation > Flashcards

Lecture 33 physio Body water - distribution and regulation Flashcards

1
Q

whats the general functions of the kidneys?

A

Water homeostasis (hydration, blood pressure)
Salt/ion homeostasis (Na+, K+, Ca2+ blood pressure)
Re-absorption of nutrients (amino acids, glucose)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What drives and regulates body water homeostasis?

A
  • distribution of body water
  • osmolarity/tonicity of solutions
  • reabsorption of water in the nephron
  • changes in body osmolarity
  • effects of osmotic changes in the kidney
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

whats the distribution of body water?

A 
TBW (55%-60%)
ICF (2/3 of TBF)
ECF (1/3 of TBW)
Plasma (1/5 of ECF)
ISF
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

whats the distribution of body water compared amongst males and females?

  • TBF
  • ICF
  • ECF
  • ISF
  • Plasma
A

males have more than females

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

whats the distribution of body water in males?

  • TBF
  • ICF
  • ECF
  • ISF
  • Plasma
A 
42L (60%)
28L
14L
11.2L
2.8L
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

whats the distribution of body water in females?

  • TBF
  • ICF
  • ECF
  • ISF
  • Plasma
A
  1. 5L (55%)
  2. 8L
  3. 7L
  4. 2L
  5. 5L
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

whats osmolarity based on?

A

number of osmotically active ions or solutes

145 mM NaCl =
145 mM Na+ + 145 mM Cl- = 290 mosmol/L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what can osmolarity be estimated by?

A

specific gravity (density of solutions)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

whats osmolarity units?

A

mosmol/L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are the terms given in osmolarity?

A

Iso - same osmolarity
Hypo - low osmolarity
Hyperosmotic - higher osmolarity solutions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Whats tonicity based on?

A

the effect of a solution on cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what does an isotonic solution not do?

A

does NOT change water homeostasis between cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

whats the osmolarity in the ECF (plasma) and ICF (muscle)?

A

275-295 mosmol/L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

body water – whats the composition of ECF (plasma) and ICF (muscle)?

Na+
K+
Ca2+
Cl-
HCO3-
pH
osmolarity
A

ECF

  • 145
  • 4-5
  • 2
  • 110
  • 24
  • 7.4
  • 275-295 mosmol/L

ICF

  • 15
  • 150
  • 10^-4
  • 5
  • 10
  • 7.1
  • 275-295 mosmol/L
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

total body water remains relatively constant.

what must the intake and loss of water be? and what is adjusted to maintain balance?

A

balance

urine output is adjusted to maintain balance (1400mL)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are the 4 important places within the nephron, where sodium is reabsorbed?

A

PCT (67%),
TAL (25%),
DCT (5%),
CCT (3%)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what are the three important places within the nephron, where water is reabsorbed?

A

PCT (67%),
tDLH (25%),
CCT (2 - 8%)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

water re-absorption in the proximal tubule (67% of the filtered load). what is it driven by?

A

Na+ reabsorption (isosmotic!!)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is water re-absorption facilitated by?

A

aquaporins (trans-cellular) and via leaky tight junctions (paracellular)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what transporters use the Na+ gradient and why?

A

transporters - sodium glucose-cotransporter use the sodium gradient to reabsorb glucose

21
Q

what does the TAL do?

A

reabsorbs Na+ into the interstitium

22
Q

whats the tDL?

A

leaky epithelium facilitating water reabsorption via aquaporins (transcellular) and the paracellular pathway

23
Q

Water

A. in the body is mostly stored in the ECF.
B. permeability of the TAL is high.
C. concentration of the urine is high under anti-diuretic conditions.
D. re-absorption in the Loop of Henle is to the same extent as sodium re-absorption.
E. balance in the body is mostly controlled by the lungs.

A

D. re-absorption in the Loop of Henle is to the same extent as sodium re-absorption.

24
Q

what does changing water content change?

A

osmolarity anf cell size

fluid shifts between ECF - ICF to equalise

volume of compartments change

25
what environment do RBC depend on? what changes the function?
isotonic environment | hypertonic or hypotonic environments
26
do ICF/ECF have same osmolarity 275-295 mosmol/L?
yes
27
where does water move?
between ICF and ECF moves to areas of high osmolarity until osmolarity equalised
28
what happens to the compartment that water moves into?
INCREASE in volume regulate water to regulate osmolarity to regulate cell size
29
changes in body osmolarity - dehydration what happens to ECF if dont drink water?
water lost (only) from ECF ECF osmolarity increases to ~ 320 mosmol/L (ECF gets more concentrated) difference between: ECF: 320mosmol/L vs ICF 285mosmol/L water moves to higher osmolarity from ICF (cells) to ECF until osmolarity balanced BUT cells will become SMALLER ECF osmolarity has to be controlled!!
30
where does water move to during dehydration not drinking? what will happen to the cells?
moves to higher osmolarity from ICF (cells) to ECF until osmolarity balanced cells will become SMALLER ECF osmolarity has to be controlled!!
31
changes in body osmolarity - hyperhydration what happens to ECF if drinks too much water?
water gained (only) by ECF ECF osmolarity decreases to ~ 240 mosmol/L now difference ECF 240 vs. ICF 285 mosmol/L
32
where does water move to during hyperhydration XS drinking? what will happen to the cells?
water moves to higher osmolarity from ECF to ICF (cells) until balanced cells are BIGGER ECF osmolarity has to be controlled!!
33
what do TBW changes alter?
plasma (ECF) osmolarity
34
TBW changes alter plasma (ECF) osmolarity hows it detected?
by osmoreceptors in hypothalamus (brain)
35
TBW changes alter plasma (ECF) osmolarity what does osmoreceptors in hypothalamus (brain) stimulate?
pituitary gland to secrete more/less ADH
36
TBW changes alter plasma (ECF) osmolarity what does ADH alter?
permeability of renal collecting duct (CD)
37
what balance initial change in TBW?
water retained/excreted - > plasma osmolarity stable - > cell volume stable
38
wheres ADH Synthesis?
- in cell body of central neurons (hypothalamus) | - axonal transport to posterior pituitary
39
where ADH release?
- in posterior pituitary | - into bloodstream (“neurosecretion”)
40
what hormone comes from the posterior pituitary?
ADH
41
whats the two major stimuli for release of ADH?
1. increased ECF osmolarity | 2. decreased blood volume
42
two major stimuli for release 1. increased ECF osmolarity 2. decreased blood volume whats the actions?
1. inserts water channels (aquaporins) in luminal membrane of CD 2. increases H2O reabsorption in the collecting duct
43
whats obligatory water reabsorption?
- not regulated!! | - accounts for 92% of total water reabsorption
44
whats facultative water reabsorption?
- tight epithelia - only transcellular - regulated by ADH - accounts for 2-8% of total water reabsorption
45
water re-absorption - CCT whats diuresis?
without ADH excessive urine large volume of diluted urine
46
water re-absorption - CCT whats anti-diuresis?
with ADH | small volume of concentrated urine
47
``` The urine osmolarity is A. high without ADH. B. independent of plasma osmolarity. C. controlled by the pituitary gland. D. independent of ADH. E. high in diuresis. ```
C. controlled by the pituitary gland.
48
What drives and regulates body water homeostasis?
* distribution (ECF, ICF, plasma and interstitium) * composition in ECF and ICF * balance (input = output, kidney) * sodium/water re-absorption in the nephron * body osmolarity (hypothalamus, pituitary gland, ADH, collecting duct, aquaporin 2)

HUBS192 (36 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions