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Endocrinology > Adrenal Gland > Flashcards

Adrenal Gland Flashcards

1
Q

Where are the adrenal glands situated?

A

Above the kidneys

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2
Q

How do you label the adrenal glands

A

As if the patient is facing you (Right on left and left on right)

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3
Q

Where does the left adrenal vein drain?

A

Into the (left) renal vein which will then drain into the inferior vena cava

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4
Q

Where does the right adrenal vein drain?

A

into the inferior vena cava

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5
Q

how many arteries and veins do each adrenal glands have?

A

both have MANY arteries but only 1 vein

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6
Q

What are each of the sections in the adrenal gland called? Starting from the outermost

A 
Adrenal cortex:
-Zona Glomerulosa
-Zona fasciculata 
-Zona reticularis
Adrenal Medulla
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7
Q

What is the adrenal cortex responsible for?

A

Secretes corticosteroids

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8
Q

What type of corticosteroid is aldosterone and where is it made?

A

mineralocorticoid

-Zona glomerulosa

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9
Q

What corticosteroid does the Zona fasciculata produce?

A

Glucocorticoids such as cortisol which is 1000x the quantity of aldosterone

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10
Q

What type of steroids are androgens and oestrogen and where are they produced?

A

sex steroids, zona reticularis

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11
Q

Why may the zona reticularis be important?

A

Produces little sex steroids in children before puberty, maybe the reason that triggers puberty

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12
Q

What does the adrenal medulla secrete? give examples

A

catecholamines:
Adrenaline/epinephrine(80%)
Noradrenaline/norepinephrine(20%)

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13
Q

what does nor in noradrenaline stand for?

A

no methyl group

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14
Q

Where is the vein in each adrenal gland found?

A

In the medulla, hence its name the central vein and all of the arteries drain into it.

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15
Q

What are steroids?

A

biologically active compounds which all come from cholesterol/ have cholesterol as their precursor

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16
Q

What is an enzyme?

A

Protein that catalyses specific reactions

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17
Q

What enzyme catalyses the reaction which turns cholesterol into pregnenolone?

A

Sidechain cleavage bc that’s what happens. (p450scc)

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18
Q

What does 3 Beta HSD stand for and what does it do?

A

3 beta hydroxy steroid dehydrogenase. It oxidises pregnenolone into progesterone.

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19
Q

What is the mechanism by which aldosterone is formed?

A

START: cholesterol -> pregnenolone-> progesterone

Progesterone is turned into 11 deoxycorticosterone by the enzyme 21 HYDROXYLASE, OH group is added onto position 21

11 deoxycorticosterone turned into corticosterone by 11 HYDROXYLASE, Oh added onto position 11

Corticosterone is turned into aldosterone by 18 Hydroxylase, adding CHO at position 18

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20
Q

What does aldosterone do?

A

Stimulates Na+ reabsorption in distal convoluted tubule and cortical collecting duct in the kidney (and in sweat glands, gastric glands, colon) by switching on an ATPase enzyme
Stimulates K+ and H+ secretion, also in distal convoluted tubule and cortical collecting duct (urinated)

water is also reabsorbed and so blood volume increases

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21
Q

What does the function of aldosterone have an effect on?

A

Blood pressure

22
Q

What hormone is made when blood pressure decreases and where from?

A

renin is made by the kidney and it stimulates a cascade

23
Q

How is aldosterone regulated?

A

Juxtaglomerular apparatus in kidney always measures blood pressure
If bp decreases, it secreted RENIN but if increased renin is suppressed.
Renin> blood stream and causes
Stimulated activation:

Renin converts Angiotensinogen(protein/hormone) from liver to Angiotensin I

Angiotensin I becomes Angiotensin II using ACE(angiotensin converting enzyme)

Angiotensin II regulates aldosterone by going to sons glomerulosa
increased ACTH, K+ and lowers Na+ in Adrenal = vasoconstriction

( check diagram )

24
Q

What enzymes does angiotensin II activate?

A 
Side Chain Cleavage
3 Hydroxysteroid dehydrogenase
21 hydroxylase
11 hydroxylase
18 hydroxylase
25
Q

What is the normal stress response regulated by

A

Cortisol

26
Q

What are the metabolic 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

27
Q

Other physiological effects of cortisol (not metabolic)

A

Weaki mineralcorticoid effects (bp)
Renal and cardiovascular effects: excretion of water load
Increased vascular permeability

28
Q

How is cortisol regulated?

A

Pituitary gland: ACTH (adrenocorticotropin hormone)
Negative feedback of cortisol to hypothalamus and pituitary gland. Hypothal - CRH (corticotropin releasing hormone) - ACTH
Called the HYPOTHALAMO PITUITARY ADRENAL AXIS

29
Q

Effects of ACTH on the adrenals

A 
Activation of enzymes :
Side chain cleavage
3 Hydroxysteroid dehydrogenase 
21 hydroxylase
17 hydroxylase
30
Q

Why could cortisol have an important role in waking you up before your alarm goes off?

A 
It has a dinural rhythm/circadian 
Level is now at midnight (if ur sleeping)
Starts increasing at 5am 
Peak at 8:30am
Then Goes down again
Tells body what time it is
(Secretes in pulses)
ACTH slightly ahead of cortisol
31
Q

What is Addison’s disease?

A

Primary adrenal failure:
Autoimmune disease where the immune system decides to destroy the adrenal cortex OR
Tuberculosis of adrenal glands
Pituitary starts secreting lots of ACTHand hence MSH (melanocyte-stimulating hormone , why tan)

32
Q

What are the signs of Addison’s disease?

A

Hyperpigmentation in skin ( get tanned for no reason)

Vitiligo- really white patches of skin

33
Q

What are the symptoms of Addison’s disease?

A

Low blood pressure bc no cortisol or aldosterone
Weakness
Weight loss

Nausea
Diarrhoea
Constipation 
Abdomminal pain
Vomiting
34
Q

What is adrenal crisis

A 
Fever
Syncope
Convulsions
Hypoglycaemia 
Hyponatremia
Severe vomiting 
Diarrhoea
35
Q

Why do patients with Addison’s disease have a good tan?

A

a large precursor protein Pro-opio-melanocortin (POMC) that is cleaved to form a number of smaller polypeptides inc ACTH and MSH.
MSH leads to the tan

36
Q

How to treat Addisons?

A

Give them hormones they’re missing

37
Q

Treatment of Addisonian crisis?

A 
Rehydrate with normal saline 
Give dextrose(iv fluid/glucose) to prevent hypoglycaemia which could be due to he glucocorticoid deficiency 
Give hydrocortisone or another glucocorticoid or artificial steroid e.g. prednisolone (longer lasting)
38
Q

What happens if you have too much cortisol?

A 
Metabolism changes
Gain weight (lose protein gain fat) - thin skin, bruising bc bv wall thinner
=CUSHINGs SYNDROME
39
Q

What can cause too much cortisol?

A

A tumour of the adrenal gland - too much cortisol
Or tumour of pituitary- too much ACTH

ACTH stops following dinural rhythm and is being made 24/7
Benign tumours

40
Q

What are the symptoms/signs of Cushing’s syndrome

A

Red cheeks
Moon face
Easy bruising - bv walls thinner bc less protein
Red striae(stretch marks) - cant make protein fast enough to cope w fat, bleeding
pendulous abdomen
poor wound healing - less protein
mental changes e.g. depression
fat pads - buffalo humps (look between the scapula)
thin skin
impaired glucose tolerance - diabetes
high blood pressure - hypertension
proximal myopathy (muscle weakness) - less protein
think arms and legs.
CENTRIPETAL OBESITY - fat in middle, thin arms and legs
immunosuppression - newly presented tb
osteoporosis
in females: amenorrhea, hirsutism
males: erectile dysfunction

((lemon on stick appearance))

41
Q

What can cause cushings syndrome?

A 
Taking steroids by mouth - too much glucocorticoid taken for another disease ( long time )- commonest
pituitary adenoma (pituitary dependent cushings disease)
Ectopic ACTH - lung cancers can sometimes make ACTH randomly
Adrenal adenoma or carcinoma
42
Q

cushings disease vs syndrome

A

disease due to pituitary adenoma

the syndrome is anyone w same signs due to too much cortisol

43
Q

what does the adrenal medulla do?

A

makes catecholamines - epipne

44
Q

what are catecholamines made from?

A

amino acids

45
Q

What is the precursor for adrenaline and noradrenaline synthesis?

A

tyrosine

46
Q

Process of tyrosine conversion to dopamine

A

tyrosine + O2 -> dopa
dopa -> dopamine + CO2
DOPAMINE = precurosor for all catecholamines
dopamine converted to nor epinephrine, then if u add methyl you get epinephrine - also has rapid effect in bp control

47
Q

Where are catecholamines stored?

A

in cytoplasmic granules and released in response to ACh from preganglionic sympathetic neurones

48
Q

What happens when catecholamines secreted?

A

flight or fight response:

tachycardia, swearing, increased bg, alertness, vasoconstriction

49
Q

In what form do NA ad Adr circulate?

A

bound to albumin

50
Q

What degrades na and adr

A

two hepatic enzymes:
monoamine oxidase
catechol-O-methyl transferase

Endocrinology (8 decks)

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