the adrenal glands Flashcards

1
Q

where are the adrenal glands?

A

above(superior to) the kidneys (ad renal)

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

describe the vasculature of the adrenal glands

A

Left adrenal vein drains into renal vein. Right adrenal vein drains into IVC. Both adrenals have many arteries but only one vein

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

what are the sections of the adrenal glands (from outside to inside)?

A

zona glomerulosa- part of adrenal cortex
zona fasciculata- part of adrenal cortex
zona reticularis- part of adrenal cortex
adrenal medulla

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

what hormones does the adrenal medulla produce?

A

catecholamines
noradrenaline/ norepinephrine
adrenaline/ epinephrine
dopamine

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

what hormones does the adrenal cortex produce?

A

corticosteroids
Mineralocorticoids (Aldosterone)
Glucocorticoids (Cortisol)
Sex steroids (Androgens, oestrogens)

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

what part of the adrenal cortex produces aldosterone?

A

zona glomerulosa

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

what part of the adrenal cortex produces cortisol and sex steroids?

A

zona fasciculata and zona reticularis

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

what is a steroid?

A

a hormone originating from cholesterol

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

how many carbons does cholesterol have?

A

27

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

what carbon does the cholesterol side chain start at?

A

carbon 20 (stems off carbon 17)

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

what enzyme converts cholesterol to pregnenolone?

A

side chain cleavage enzyme

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

what enzyme converts pregnenolone to progesterone?

A

3 beta hydroxy steroid dehydrogenase

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

what enzyme converts progesterone to 11 deoxycorticosterone?(aldosterone production)

A

21 hydroxylase

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

what enzyme converts 11 deoxycorticosterone to corticosterone?(aldosterone production)

A

11 hydroxylase

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

what enzyme converts corticosterone to aldosterone?

A

18 hydroxylase

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

what enzyme converts progesterone to 17-hydroxyprogesterone?(cortisol production)

A

17 hydroxylase

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

what enzyme converts 17-hydroxyprogesterone to 11 deoxy-cortisol?(cortisol production)

A

21 hydroxylase

18
Q

what enzyme converts 11 deoxy-cortisol into cortisol?

A

11 hydroxylase

19
Q

what is the net effect of aldosterone?

A

conserve body sodium by stimulating its reabsorption

20
Q

what is aldosterone’s mechanism of action?

A

Stimulates Na+ reabsorption in distal convoluted tubule and cortical collecting duct in kidney (and in sweat glands, gastric glands, colon)
Stimulates K+ and H+ secretion, also in distal convoluted tubule and cortical collecting duct
Increased sodium reabsorption water reabsorption,
raising blood volume

21
Q

outline how aldosterone is regulated

A

renin is produced
this turns angiotensinogen into angiotensin I
ACE then turns this into angiotensin II which has effects like vasoconstriction
this also increases aldosterone production

22
Q

how is renin released?

A

when blood pressure falls in kidney
Decreased renal perfusion pressure (normally associated with decreased arterial BP)

Increased renal sympathetic activity (direct to JGA(juxtaglomerular apparatus) cells)

Decreased Na+ load to top of loop of Henle (macula densa cells)

23
Q

what enzymes does angiotensin II effect?

A
Activation of the following enzymes
Side Chain Cleavage
3 Hydroxysteroid dehydrogenase
21 hydroxylase
11 hydroxylase
18 hydroxylase
24
Q

what are the effects of cortisol?

A

peripheral protein catabolism
hepatic gluconeogenesis
increased blood glucose concentration
fat metabolism (lipolysis in adipose tissue)
enhanced effects of glucagon and catecholamines
excretion of water load
increased vascular permeability

25
Q

how is cortisol production regulated?

A

through ACTH

and negative feedback(cortisol causes hypothalamus and anterior pituitary to reduce ACTH)

26
Q

what enzymes does ACTH act on in the adrenal glands?

A
Side Chain Cleavage
3 Hydroxysteroid dehydrogenase
21 hydroxylase
11 hydroxylase
17 hydroxylase
27
Q

what happens to cortisol levels during the day?

A

fluctuates
lowest at midnight highest at 8:30
regulates time of day (circadian rhythm)
(ACTH levels rise before)

28
Q

what is addison’s disease?

A

Primary adrenal failure
Autoimmune disease where the immune system decides to destroy the adrenal cortex (UK)
Tuberculosis of the adrenal glands (commonest cause worldwide)
large amounts of ACTH and MSH

29
Q

what are the symptoms of addison’s disease?

A
hyperpigmentation
vitiligo
low blood pressure
weight loss
weakness
nausea
diarrhoea
vomiting
constipation
abdominal pain
30
Q

what are the signs of an adrenal crisis?

A
fever
syncope
convulsions
hypoglycaemia
hyponatremia
severe vomiting and diarrhoea
31
Q

what causes the tan in addison’s disease?

A

pro-opio-melanocortin(POMC) is a precursor to ACTH
so if lots of ACTH is being made lots of POMC is made
the other product of POMC breakdown is MSH which causes a tan

32
Q

how do you treat an addisonian crisis?

A

saline
dextrose
hydrocortisone (or another glucocorticoid

33
Q

what is cushing’s syndrome?

A

large amounts of cortisol

34
Q

what could cause cushing’s syndrome?

A

Taking steroids by mouth (common)
pituitary dependent Cushing’s disease (pituitary adenoma)
Ectopic ACTH (lung cancer)
adrenal adenoma or carcinoma

35
Q

what are the symptoms of cushing’s syndrome?

A
Thin skin
Proximal myopathy
Centripetal obesity (lemon on sticks)
Diabetes, hypertension and osteoporosis
Immunosuppression (reactivation of TB)
Moon face
Striae
emotional disturbances
etc
36
Q

what amino acid is the precursor to adrenaline and noradrenaline?

A

tyrosine

37
Q

how are the catecholamines stored?

A

in cytoplasmic granules

38
Q

what causes the catecholamines to be released?

A

released in response to ACh from preganglionic sympathetic neurones

39
Q

what is the role of catecholamines?

A

fight or flight

e.g. tachycardia, sweating, increased blood glucose, alertness, vasoconstriction

40
Q

how are catecholamines transported in blood?

A

bound to albumin

41
Q

what enzymes degrade the catecholamines?

A

Degraded by two hepatic enzymes: monoamine oxidase & catechol-O-methyl transferase