Brainscape's Knowledge GenomeTM

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


See full index

BRS YEAR 2 > Endo - Disorders of Vasopressin > Flashcards

Endo - Disorders of Vasopressin Flashcards

1
Q

What type of neurones are found in the PPG?

A

Mangocellular neurones

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

Why is the PPG neural in origin?

A

it develops continuously with the hypothalamus

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

Where do magnocellular neurones originate from?

A

Supraoptic and paraventricular nucleus

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

What are the PPG hormones?

A

AVP

Oxytocin

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

What is the physiological action of AVP?

A

Concentrations urine in the collecting duct

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

What does AVP bind to?

A

V2 receptors

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

What type of receptor is V2?

A

G protein coupled

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

What does V2 binding stimulate?

A

Adenylate cyclase leads to cAMp and protein kinase A activity which leads to aquaporin 2 channels to move to the apical membrane of tubular cells

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

What does the PPG normally show in an MRI?

A

Bright spot

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

Is the PPG always seen in health?

A

No

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

What are the 2 ways vasopressin release is stimulated?

A

Osmotic and non osmotic

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

What is the osmotic route of AVP stimulation?

A

Increase in plasma osmolarity is sensed by hypothalamic osmoreceptors

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

What is the non osmotic route of AVP stimulation?

A

Decreased blood volume leads to less atrial stretch detected by stretch receptors

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

Where are osmoreceptors found mainly?

A

In the hypothalamus in the subfornical organ and the organum vasculosum

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

What is an advantage of the osmoreceptors?

A

They lack a blood brain barrier therefore respond directly to the systemic circulation

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

Where do osmoreceptor neurones project?

A

Into the supraoptic nucleus which is a site of vasopressinergic neurones

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

Outline how water deprivation increases AVP secretion

A

Increase in plasma Na means that water leaves the osmorecpetors due to osmotic balance, osmoreceptor shrinking leads to increased firing and thus increased AVP release

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

Where are atrial stretch receptors found?

A

Right atrium

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

How do atrial stretch receptors work?

A

They are usually inhibitory on AVP secretion via the vagus nerve

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

Outline how water deprivation causes AVP release non osmotically?

A 
Decrease in water
Decrease in blood volume
Less stretch detected
Disinhibition by less firing 
AVP release
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Why is AVP released following a haemorrhage?

A

Following a haemorrhage there us a lower circulating volume, this allows for us to try and increase our blood pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Alongside AVP release, what else happens during a haemorrhage?

A

We get vasoconstriction by AVP acting on V1 receptors

Junta glomerular apparatus stimulates aldosterone release to increase blood volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Alongside AVP release, how else do we correct plasma osmolarity?

A

Stimulation of osmoreceptors increases thirst therefore plasma osmolarity is reduced when drinking

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is diabetes insipidus?

A

When there is a problem with insufficient AVP effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are the symptoms for diabetes insipidus?

A

Polyuria
Polydipsia/extreme thirst
Nocturia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the more common form of diabetes?

A

Mellitus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Why does diabetes mellitus cause osmotic symptoms?

A

Increase in blood glucose
Water enters blood due to osmotic effect
Increased water loss in urine

28
Q

Describe urine production in diabetes insipidus

A

Large volume, hypo-osmoloar urine

29
Q

Describe the plasma in diabetes insipidus

A

Hyper-osmolar with increasing thirst
Hypernatremia
Normal glucose

30
Q

What are the 2 types of diabetes insipidus

A

Cranial

Nephrogenic

31
Q

What is the more common form of diabetes insipidus

32
Q

What happens in cranial diabetes insipidus

A

Problem with hypothalamus or pituitary whereby we don’t make sufficient AVP

33
Q

What happens in nephrogenic diabetes insipidus

A

AVP production is normal but collecting duct doesn’t respond - vasopressin resistance

34
Q

What are the causes of congenital cranial diabetes insipidus

35
Q

What are the causes for acquired cranial diabetes insipidus

A 
Traumatic brain injury
Pituitary surgery
Pituitary tumours
Metastasis (breast to pituitary)
Granulomatous infiltration of pituitary stalk e.g. TB, sarcoidosis.
Autoimmune
36
Q

How does granuloma cause cranial diabetes insipidus?

A

Stalk inflammation causes thickening thus preventing passage of AVP

37
Q

What are the causes of congenital nephrogenic diabetes insipidus

A

Rare e.g. V2 receptor or aquaporin 2 gene mutation

38
Q

What are the causes of acquired nephrogenic diabetes insipidus

A

Drugs e.g. lithium

39
Q

What is the treatment for cranial diabetes insipidus

A

Desmopressin - oral or intranasal

40
Q

What does desmopressin act on?

A

V2 receptors - not V1 receptors

41
Q

What is the treatment for nephrogenic diabetes insipidus?

A

Thiazide diuretics e.g. bendrofluazide

42
Q

How can diabetes insipidus cause death?

A

We constantly lose water through lack of AVP mechanism therefore if we don’t drink water and the DI is not managed correctly, we die

43
Q

qWhat is psychogenic polydipsia?

A

Mental health disorder in which the patient drinks too much water - seen in the context of other mental health disorders

44
Q

What are the symptoms of psychogenic polydipsia?

A

Polyuria
Nocturia
Polydipsia

45
Q

How do we distinguish DI from PD?

A

Water deprivation test

46
Q

What happens in a water deprivation test?

A

We give the patient nothing to drink over the course of a few hours

47
Q

What do we measure in water deprivation test?

A

Urine volume
Urine osmolarity
Plasma concentration
Body weight

48
Q

When do we stop a water deprivation test?

A

If patient loses more than 3% of their body weight indicating significant dehydration

49
Q

What do we see in a water deprivation test for normal patient

A

As we have less water, AVP increases therefore urine osmolarity increases

50
Q

What do we see in a water deprivation test for PD

A

Water deprivation means AVP still works, but it is generally lower osmolarity than normal person due to large amounts of dilute urine

51
Q

What do we see in a water deprivation test for DI

A

AVP problem therefore urine is never concentrated, osmolarity stays low

52
Q

How do we distinguish between CDI and NDI?

A

We give desmopressin

53
Q

What do we see in CDI deprivation test?

A

CDI responds, urine osmolarity rises

54
Q

What do we see in NDI deprivation test?

A

NDI is resistant to ddAVP therefore osmolarity of urine is unaffected

55
Q

What is a normal plasma osmolality

A

280 mOsm/kg H20

56
Q

What is the plasma osmolarity for DI?

57
Q

What is the plasma osmolarity for PD?

58
Q

What is Syndrome of Inappropriate ADH?

A

Too much AVP

59
Q

What are the effects of SIADH?

A 
Water retention 
Low urine output
High urine osmolarity
Low plasma osmolarity
Dilution hyponatremia
60
Q

What are the 5 main causes of SIADH?

A 
Drugs
Idiopathic 
Pulmonary disease
Malignancy
CNS causes
61
Q

What malignancies cause SIADH

A

Small cell lung cancer

62
Q

What drugs cause SIADH

A

SSRIs

Carbamazepine

63
Q

What pulmonary diseases cause SIADH

A

Bronchiectasis

Pneumonia

64
Q

What CNS problems cause SIADH

A

Head injury
Stroke
Tumour

65
Q

How do we manage SIADH

A

Vaptan - V2 receptor antagonist (very expensive)

BRS YEAR 2 (37 decks)

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