Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

ESA3 > Urinary 6 - Plasma osmolarity (disorders + diuretics) > Flashcards

Urinary 6 - Plasma osmolarity (disorders + diuretics) Flashcards

(84 cards)

Start Studying
1
Q

What are the main receptors in the body that detect changes in plasma osmolarity, and where are they located?

A

Hypothalamic osmoreceptors

Organum Vasculosum of Lamina Terminalis (OVLT)

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

How do the hypothalamic osmoreceptors respond if they detect increased osmolarity?

A
  • Increase thirst stimulus

- Increase ADH secretion

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

For the hypothalamic osmoreceptors to increase the thirst response, what change in osmolarity must be detected?

A

Increased osmolarity by 10%

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

For the hypothalamic osmoreceptors to change ADH secretion rate, what change in osmolarity must be detected?

A

Increased or decreased osmolarity by 1%

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

How does an increase in ADH secretion cause reduction of plasma osmolarity?

A

ADH increases the insertion of AQP2 into the apical membrane of principal cells of collecting ducts = increased water reabsorption

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

Which aquaporin channels are controlled by ADH?

A

AQP2 in the principle cells of the collecting duct

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

ADH mediates aquaporin insertion in what part of the kidney tubule?

A

Collecting ducts (principle cells)

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

Which aquaporin channels are present in the apical membrane of the PCT?

A

AQP1

AQP7

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

Which aquaporin channels are present in the apical membrane of the descending LoH?

A

AQP1

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

Which aquaporin channels are present in the basolateral membranes of the PCT and descending LoH?

A

AQP1

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

Which aquaporin channels are present in the basolateral membrane of the collecting ducts?

A

AQP3

AQP4

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

List some causes of Central Diabetes Insipidus:

A

Damage to hypothalamus and/or pituitary gland:

  • Brain injury (particularly fracture of base of skull)
  • Meningitis
  • Brain tumour
  • Sarcoidosis
  • TB
  • Encephalitis
  • Aneurysm
  • Langerhans cells histiocytosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the pathophysiology of central diabetes insipidus?

A

Damage to hypothalamus and/or pituitary gland
= lack of circulating ADH
= inadequate reabsorption of H2O from collecting ducts

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

What are the symptoms of central diabetes insipidus?

A

Polyuria

Polydipsia

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

What is the treatment of central diabetes insipidus?

A

ADH nasal spray

ADH injections

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

List some causes of Nephrogenic Diabetes Insipidus:

A
  • Hereditary
  • Acquired (Lithium, hypercalcaemia, hypokalaemia, polycystic kidney disease, sickle cell anaemia, severe pyelonephritis)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the inheritance pattern of hereditary nephrogenic diabetes insipidus?

A

X-Linked Recessive

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

What is the pathophysiology of nephrogenic diabetes insipidus?

A

Kidney is less sensitive to ADH

= Inadequate reabsorption of H2O from collecting ducts

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

What are the symptoms of Nephrogenic Diabetes Insipidus?

A

Polydipsia

Polyuria

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

What are the treatments for Nephrogenic Diabetes Insipidus?

A 
Mild:
- Reduced intake of salt and protein
- Adequate water intake
More severe:
- NSAIDs
- Thiazide diuretics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does SIADH stand for?

A

Syndrome of Inappropriate ADH secretion

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

List some causes of SIADH:

A
  • Nervous system disorders (MS, encephalitis, infection, epilepsy)
  • Brain injury
  • Drug induced (Lithium, antidepressants, opiates)
  • Pulmonary disorders (Infection, asthma, CF)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Describe the pathophysiology of SIADH:

A

Excessive release of ADH
= Massive volume expansion
= Hyponatraemia

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

List some symptoms of SIADH:

A

Nausea/Vomiting
Cramps/Tremors/Seizures
Depressed mood/Irritability/Confusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is the treatment for SIADH?
- Treat underlying cause - Fluid restriction - Na+ replacement (IV hypertonic saline) - ADH receptor antagonists
26
Define diuretic:
Substance which promotes diuresis by increasing renal excretion of H2O and Na+, to decrease ECF volume
27
List the 5 classes of diuretic:
1) Loop 2) Thiazide 3) K+ Sparing 4) Carbonic Anhydrase inhibitors 5) Osmotic
28
What is the mechanism of action of Loop diuretics?
Block NKCC2 in TAL (Thick ascending limb of LoH)
29
What class of diuretic does Furesomide belong in?
Loop diuretic
30
What type of diuretic is the most powerful?
Loop diuretics
31
What conditions are Loop diuretics used to treat?
- Heart failure - Fluid retention and oedema in Nephrotic syndrome, Liver cirrhosis and renal failure - Hypercalcaemia
32
What are the main complications of Loop diuretics?
- Hypokalaemia - Dehydration - Hyperuricaemia = Gout attack - Hyponatraemia (less common)
33
Give an example of a diuretic that acts on the TAL (Thick ascending limb of LoH):
Furosemide
34
What class of diuretics block NKCC2 channels?
Loop diuretics
35
What is the mechanism of action of Thiazide diuretics?
Block Na+/Cl- symporter in the DCT
36
What class of diuretic does Metolazone belong to?
Thiazide diuretics
37
What is the preferred diuretic used in patients with osteoporosis, and why?
Thiazide diuretics | Increase Ca2+ reabsorption
38
What condition is commonly treated with Thiazide diuretics?
Hypertension
39
Which diuretic is most commonly used to treat hypertension?
Thiazide diuretics
40
What are the main complications of Thiazide diuretics?
- Hypokalaemia - Hyponatraemia - Hyperuricaemia = Gout attack - Hyperglycaemia - Hyperlipidaemia - Erectile dysfunction
41
Give an example of a diuretic that acts on the DCT:
Metolazone (Thiazide) | Amiloride (K+ sparing ENaC blocker)
42
Which class of diuretics block the Na+/Cl- symporter?
Thiazide diuretics
43
What is the mechanism of action of K+ sparing diuretics?
EITHER: 1 - Inhibition of ENaC in DCT and collecting duct 2 - Aldosterone antagonist
44
What class of diuretic does Amiloride belong to?
K+ Sparing (ENaC inhibition)
45
What class of diuretics does Spironalactone belong to?
K+ sparing (Aldosterone antagonist)
46
What are ENaC blockers used for?
Used alongside K+ losing diuretics, to minimise K+ loss
47
What conditions are commonly treated with Aldosterone antagonists?
- Hypertension (if caused by Conn's syndrome) - Ascites and Oedema in Cirrhosis - Heart failure (with loop diuretics)
48
What is the main complication of K+ sparing diuretics?
- Hyperkalaemia
49
What may increase the risk of hyperkalaemia occurring when taking K+ sparing diuretics?
- ACEi - K+ supplements - Renal impairment
50
To which class of diuretics do ENaC blockers belong?
K+ Sparing diuretics
51
Give an example of a diuretic that acts on the collecting ducts:
Amiloride (K+ sparing ENaC blocker) | Spironolactone (K+ Sparing aldosterone antagonist)
52
To which class of diuretics do Aldosterone antagonists belong?
K+ sparing
53
What class of diuretic does Acetazolamide belong to?
Carbonic Anhydrase inhibitor
54
What condition are Carbonic Anhydrase inhibitors used for?
Glaucoma
55
What is the main complication caused by Carbonic Anhydrase Inhibitors?
Metabolic acidosis (increases HCO3- loss)
56
What is the mechanism of action of osmotic inhibitor diuretics?
Small inert molecules increase the osmolarity of blood and filtrate = Increased driving force for H2O loss
57
What class of diuretics does Mannitol belong to?
Osmotic Inhibitor diuretics
58
What condition can be treated with osmotic inhibitor diuretics?
Cerebral oedema
59
By what mechanisms can Loop and Thiazide diuretics cause hypokalaemia?
1 - Increased Na+ delivery to late DT/collecting ducts = Increased Na+ reabsorption (ENaC) = Increased K+ secretion (ROMK down favourable electrical gradient) 2 - Increased flow rate in lumen = Secreted K+ is washed away faster (reduced local conc.) = Increased K+ secretion (ROMK down favourable concentration gradient) 3 - Decreased ECF = RAAS activation = Increased Aldosterone activation = Increased Na+ absorption and K+ secretion
60
Which diuretics can cause hypokalaemia?
Loop diuretics | Thiazide diuretics
61
Which diuretics can cause hyperkalaemia?
K+ Sparing diuretics
62
Which diuretics can cause hyponatraemia?
``` Thiazide diuretics Loop diuretics (less likely) ```
63
Which diuretics can cause hyperuricaemia?
Loop diuretics | Thiazide diuretics
64
Which diuretics can cause hyperglycaemia and hyperlipidaemia?
Thiazide diuretics
65
Which diuretics can cause erectile dysfunction?
Thiazide diuretics
66
What is a complication of Spironolactone diuretics?
Gynaecomastia
67
Which diuretics can cause gynaecomastia?
Spironolactone
68
How do Spironolactone diuretics cause gynaecomastia?
Decreased testosterone production and Increased peripheral conversion of Testosterone to Estradiol
69
How does Alcohol cause diuresis?
Inhibits ADH release
70
How does coffee cause diuresis?
- Increased GFR | - Decreased tubular reabsorption of Na+
71
How does Lithium cause diuresis?
Inhibits ADH action on collecting ducts
72
How does hyperglycaemia cause diuresis?
Increased osmolarity of plasma and filtrate
73
How does psychogenic polydipsia cause diuresis?
Increased fluid intake = increased fluid loss
74
Which nephrons have a vertical osmotic gradient?
Juxtamedullary nephrons only
75
What is the concentration of the filtrate when it reaches the distal tubule of juxtamedullary nephrons?
100 mosm/L
76
Describe the relationship between the vasa recta and a juxtamedullary nephron:
Flow of the vasa recta is in opposite direction to the tubule: - Desc. limb of vasa recta accompanies the asc. limb of LoH - Asc. limb of vasa recta accompanies the desc. limb of the LoH
77
Na+, Cl- and Urea diffuse into which limb of the vasa recta?
Descending limb
78
H2O diffuses into which limb of the vasa recta?
Ascending limb
79
What type of nephrons can produce hyper/hypotonic urine?
Juxtamedullary nephrons
80
What is the maximum concentration of urine?
1200 mosm/L
81
What is the average concentration of urine?
300 mosm/L
82
ADH binds to which cells in the kidney?
Principal cells in the collecting duct
83
Where is ADH produced and secreted from?
Produced - hypothalamus | Secreted from - posterior pituitary
84
How does ADH cause increased water reabsorption across the principle cells of the collecting duct?
ADH induces the relocation of AQP2 into the apical membrane

ESA3 (48 decks)

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