Basic Functions of the Adrenal Gland Flashcards

1
Q

What causes adrenal insufficiency?

A
  • Glucocorticoid deficiency
  • Mineralocorticoid deficiency
  • Adrenal androgen deficiency
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2
Q

Can corticosteroids pass through membranes?

A

Yes, they are lipid soluble

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3
Q

What causes Cushing’s syndrome?

A

Excess glucocorticoid

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4
Q

Effect(s) of excess glucocorticoid on brain/CNS

A
  • Depression
  • Psychosis
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5
Q

Effect(s) of excess glucocorticoid on eyes

A

Glaucoma

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6
Q

Effect(s) of excess glucocorticoid on pituitary

A
  • Decreased LH/FSH release
  • Decreased TSH release
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7
Q

Effect(s) of excess glucocorticoid on GIT

A

Peptic ulcerations

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8
Q

Effect(s) of excess glucocorticoid on carb/lipid metabolism

A
  • Hepatic glycogen deposition
  • Peripheral insulin resistance
  • Gluconeogenesis, diabetes
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9
Q

Effect(s) of excess glucocorticoid on adipose tissue distribution

A

Promotes visceral obesity

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10
Q

Effect(s) of excess glucocorticoid on cardiovascular/renal

A
  • Salt and water retention
  • Hypertension
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11
Q

Effect(s) of excess glucocorticoid on skin/muscle/connective tissue

A
  • Protein catabolism/collagen breakdown
  • Skin thinning
  • Muscular atrophy
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12
Q

Effect(s) of excess glucocorticoid on bone and calcium metabolism

A
  • Decreased bone formation
  • Decreased bone mass, osteoporosis
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13
Q

Effect(s) of excess glucocorticoid on growth and development

A

Decreased linear growth

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14
Q

Effect(s) of excess glucocorticoid on immune system

A
  • Anti-inflammatory action
  • Immunosuppression
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15
Q

What percentage of glucocorticoids in circulation are bioavailable?

A

5%

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16
Q

What are glucocorticoids bound to in circulation (and what percentage bound to each)?

A
  • Corticosteroid-binding globulin (CBG) (90%)
  • Albumin (5%)
17
Q

What happens to CBG levels with inflammation?

A

They decrease (so more glucocorticoid bioavailable)

18
Q

What system regulates glucocorticoid synthesis?

A

Hypothalamic-pituitary-adrenal (HPA) axis

19
Q

Sequence of the HPA axis

A
  • Hypothalamus releases corticotropin-releasing hormone (CRH)
  • Anterior pituitary releases adreno-corticotropic hormone (ACTH)
  • Adrenal cortex releases cortisol
20
Q

What factors cause stress?

A
  • Infection
  • Trauma
  • Haemorrhage
  • Medical illness
  • Psychological
  • Exercise/exhaustion
21
Q

What are the main mineralocorticoids?

A
  • Aldosterone
  • DOC
22
Q

What are mineralocorticoids critical to?

A

Salt and water balance in:
- Kidney
- Colon
- Pancreas
- Salivary glands
- Sweat glands

23
Q

Why does cortisol need to be deactivated for aldosterone binding?

A
  • The 2 bind the same receptor
  • Cortisol has a much higher concentration so will swamp aldosterone
24
Q

What is the deactivated form of cortisol and what enzyme converts it to that?

A
  • Cortisone
  • Enzyme = 11β-hydroxysteroid
25
What is the most abundant adrenal steroid?
Dehydroepiandrosterone (DHEA)
26
What are the main sources of androgens in men and women?
- Men = testicles - Women = adrenal glands
27
What regulates adrenal androgen production?
ACTH
28
What is the main site of catecholamine synthesis?
Adrenal medulla
29
Percentages of different catecholamine productions
- Adrenaline = 80% - Noradrenaline = 20% - Dopamine = small amounts
30
What receptors do catecholamines act through?
Adrenergic receptors
31
Action(s) of catecholamines on CNS
Increased alertness
32
Action(s) of catecholamines on respiratory
Increased breathing rate
33
Action(s) of catecholamines on heart
- Increased contractility - Increased blood pressure - Increased heart rate
34
Action(s) of catecholamines on adipose tissue
Lipolysis
35
Action(s) of catecholamines on liver
- Gluconeogenesis - Glucose release
36
Action(s) of catecholamines on muscles
Gluconeogenesis