Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physiology 1 > Control And Abnormalities Of Body Water > Flashcards

Control And Abnormalities Of Body Water Flashcards

1
Q

How is volume regulation maintained in the body?

A

Retaining sodium (and water with it)

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

What is osmoregulation?

A

Preventing shifts of water between the ECF and ICF

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

How is the osmolarity of the ECF adjusted?

A

Adding or removing water in the body (thirst mechanism or kidney)

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

What is the only site of regulated water loss?

A

Renal tubule

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

What happens to the urine if there’s a water excess?

A

Large volume of dilute urine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What happens to the urine if there’s a water deficit?

A

Small volume of concentrated urine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the two ways the kidney osmoregulate?

A

Concentrate interstitial fluid in the medulla, dilute urine in ascending limb and distal tubule

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

What is the threshold for urine concentration?

A

50 - 1200 mOsm/L

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

What are the concentration difference between the interstitial fluid and tubular fluid in the proximal tubule?

A

Isotonic

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

Where do you get the max concentration of both the interstitial and tubular fluid?

A

Bend of the loop of henle

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

Where do you get the maximum dilution of the tubular fluid?

A

Distal tubule

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

What is the osmoregulatory hormone?

A

ADH

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

What does lack of ADH in the collecting duct mean?

A

It’s impermeable to water and therefore maximally dilute urine is secreted

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

What urine osmolality is meant to signify the presence of ADH?

A

> 100mOsm/Kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

At maximum ADH levels what is the limit of water reabsorption set by?

A

The osmolality of the medullary interstitial fluid

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

What is ADH’s mechanism of action?

A

Vasopressin V2 receptors act on principal cells and get them to make and insert aquaporin 2 channels into the membrane

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

What do V1 receptors on vascular smooth muscle lead to?

A

Vasoconstriction but only significant with very high ADH levels

18
Q

How does a net water loss change ECF osmolality?

A

Increase

19
Q

What is the normal ECF osmolality range?

A

285-295 mOsm/Kg

20
Q

Where are changes in osmolality detected?

A

Osmoreceptors in the anterior hypothalamus

21
Q

Where do the osmoreceptors project to?

A

Magnocellular neurons of the paraventricular and supraoptic nucleus of the hypothalamus

Or thirst centres

22
Q

What do the paraventricular and supraoptic nucleus release?

A

ADH

23
Q

Where do the paraventricular and supraoptic nuclei release ADH from?

A

The axon terminus in the posterior pituitary glands

24
Q

What is the threshold for ADH release?

A

280-285 mOsm/Kg

25
Q

Above the range, what do small changes in osmolality lead to?

A

Large changes in ADH secretion

26
Q

When do you get a strong desire to drink?

A

Plasma osmolality > 295 mOsm/Kg

27
Q

What else can thirst be stimulated by?

A

Large drops in blood volume/ pressure and angiotensin 2 acting on hypothalamus

28
Q

What is the main determinant of ECF osmolality?

A

Plasma [Na+]

29
Q

What formula do you use to estimate plasma osmolarity?

A

2[Na+] + 2[K+] + [glucose] + [urea]

30
Q

What is hypernatraemia?

A

Too little water (too much sodium)

31
Q

What are the causes of hypernatraemia?

A

Gain of sodium or loss of water (more common)

32
Q

How can you gain sodium?

A

Iatrogenic, excess ingestion, excess mineralocorticoid activity

33
Q

What does iatrogenic mean?

A

Unintended side effect of medical treatment

34
Q

What can cause a loss of water?

A

Extrarenal losses (dehydration/infection)

Renal losses (osmotic diuresis/ diabetes insipidus)

35
Q

What is osmotic diuresis?

A

Impaired tubular fluid dilation meaning the osmotic gradient is off so water reabsorption is decreased

36
Q

What causes diabetes insipidus?

A

Lack of effective ADH- either due to a failure of secretion (central) or a lack of renal response (nephrogenic)

37
Q

What does hypoosmotic hypernatraemia signify?

A

Water excess

38
Q

When does pseudohyponatraemia occur?

A

When some other solute conc is high enough that sodium has to be reduced to maintain electro neutrality

39
Q

What can cause syndrome of inappropriate ADH secretion?

A

CNS damage/ disease and ectopic ADH production by tumour

40
Q

What does syndrome of inappropriate ADH secretion cause?

A

Hyponatraemia and high urine osmolarity

41
Q

Which is more powerful- low volume/ pressure or osmotic signals?

A

Low volume/ pressure

42
Q

What happens in kidneys in congestive heart failure?

A

RAAS -> sodium/ water retention (volume expansion) -> ineffective because dodgy starling forces -> oedema

Physiology 1 (65 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions