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Yr 3 > Pituitary adrenal axis > Flashcards

Pituitary adrenal axis Flashcards

1
Q

what is the adrenal gland consisted of

A

cortex and medulla

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2
Q

what are the hormones of the adrenal gland used for

A

regulators of metabolism and adaptation to stress

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3
Q

what is cortisol and what does it do

A

glucocorticoid and increases plasma glucose levels

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4
Q

a deficiency in cortisol leads to what

A

hypoglycaemia

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5
Q

what is aldosterone

A

mineralocorticoid

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6
Q

what does aldosterone do

A

promotes salt and water retention by the kidney

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7
Q

what else does the adrenal cortex synthesise and secrete and what are they converted to

A

androgenic steroids
converted by peripheral tissue to testosterone

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8
Q

what is the primary product of chromaffin in the medulla

A

adrenaline, also produces adrenaline precursor
noradrenaline
[catecholamines]

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9
Q

name the layers of the adrenal gland, outside -> in

A

capsule
zona glomerulosa
zona fasciculata
zona reticularis
medulla

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10
Q

what zona is responsible for producing aldosterone

A

zone glomerulosa

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11
Q

what zona is responsible for producing cortisol

A

zona fasciculata

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12
Q

what zona is responsible for producing weak androgens

A

zona reticularis

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13
Q

what do aldosterone, cortisol and weak androgens all have in common

A

they’re all steroid hormones

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14
Q

(1)MODULATING OUR STRESS RESPONSE
stressful stimuli causes what in the hypothalamus

A

to activate the adrenal cortex via hormonal signals

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15
Q

(2)MODULATING OUR STRESS RESPONSE
adrenal cortex secrets what and why

A

mineralocorticoids and glucocorticoids
because the adrenal cortex was sent stimuli (activating it) by the hypothalamus via hormonal signals

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16
Q

what are effects of mineralcorticoids

A

retention of water ions and water by kidney
increased blood volume and blood pressure

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17
Q

what are effects of glucocorticoids

A

proteins and fats are broken down and converted t glucose, leading to increased blood glucose
partial suppression of immune system

18
Q

what are all steroid hormones derived from

A

cholesterol

19
Q

what binding globulin transports cortisol

A

corticosteroid binding globulin

20
Q

enzymes which produce steroid hormones from cholesterol are located where

A

mitochondria and SmER

21
Q

what is the rate limiting step in converting cholesterol to steroid hormones and what protein carries out this step

A

transport of free cholesterol from the cytoplasm into the mitochondria
StAR -> moves cholesterol from outer membrane to the inner membrane where cholesterol is converted t pregnenolone (precursor)

22
Q

in the adrenal cortex how many pathways can pregnenolone be converted to

A

3
mineralocorticoids
glucocorticoids
androgens

23
Q

adrenal steroidogenesis
what determines which pathway is taken

A

Each step of the pathway is regulated by a specific enzyme.
Different zones of the adrenal cortex have different relative activities of enzymes, resulting in different chemical reactions taking place.

24
Q

liver is predominant site of what

A

steroid inactivation

25
Q

if the adrenal cortex is not functioning or is removed what must be administered

A

exogenous glucocorticoids

26
Q

the actions of glucocorticoids are essential for what

A

gluconeogenesis, for vascular responsiveness to catecholamines
-> for suppression of inflammatory and immune responses and modulation of CNS function

27
Q

glucocorticoids are essential for survival during what

A

fasting

28
Q

what are metabolic effects of cortisol (stimulation)

A

Stimulates protein and triglyceride catabolism
Stimulates “gluconeogenesis” in liver

29
Q

WHAT ARE THE METABOLIC EFFECTS OF CORTISOL (INHIBITORY)

A

Inhibits bone formation
Inhibition of non-essential functions (reproduction; growth)
Inhibition of glucose uptake by body (insulin antagonism) but not by brain. Elevates blood glucose levels, “diabetogenic effect.” Nervous system becomes primary user of glucose during stress.

30
Q

when is cortisol prescribed

A

to suppress inflammation and the immune response

31
Q

what happens when cortisol levels are high

A

many of the body’s defence mechanisms against infection are inhibited

32
Q

what is the activation of glucocorticoid response element (GRE) mediated transcription used for

A

alterations in water balance, weight gain, hypertension, muscle weakness, diabetes, and osteoporosis. These side effects are mediated through the genomic function of GR

33
Q

what disease is linked with hypocortisolism and what hypo/hyperglycaemia?

A

addisons disease
hypoglycaemia

34
Q

what syndrome is linked with hypercortisolism and hyper/hypoglycaemia

A

Cushing’s syndrome
hyperglycaemia

35
Q

what happens if there is a pituitary lesion or no ACTH

A

fasciculata and reticularis atrophy
-> no cortisol; dependency on exogenous glucocorticoids

36
Q

what happens if there is excess ACTH

A

enlarged adrenal glands -> enlarged steroids

37
Q

if the HPA axis is over stimulated because of stress, and if the body cannot keep up with the demand for cortisol, of if there is any other steroidogenic block what happens

A

excess ACTH might be shunted int the androgen production pathway

38
Q

what is Cushing’s syndrome

A

increased glucocorticoid production (hypercortisolism)
caused by basophilic adenoma

39
Q

what are the two primary consequences of Cushings syndrome

A
  1. moon face (salt/water retention with renal loss of K+)
    -> leads to cardiac hypertrophy due to prolonged hypertension
    2.catabolism causes
    muscle wating, fat accumulation, osteopersis with kyphosis, buffalo hump and fractures, thin skin with ulcers and red stirrer
    poor wound healing
40
Q

Addisons disease main symptom

A

overproduction of ACTH due to decreased negative feedback by cortisol

41
Q

what causes addisons disease

A

adrenal glands do not produce suffiecient steroid hormones (glucocorticoids and mineralocorticoids
decreased by negative feedback

Yr 3 (15 decks)

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