Adrenal cortex

Question 1

Which zone is responsible for synthesising mineralcorticoids

Answer 1

Zona glomerulosa

Question 2

Name a mineralcorticoid

Answer 2

Aldosterone

Question 3

The zona fasciculata synthesises what?

Answer 3

Glucocortoids (cortisol)

Question 4

What does the zona reticularis synthesis?

Answer 4

Androgens

Question 5

What is the precursor of steroid hormones?

Answer 5

Cholesterol

Question 6

The synthesis of sex hormones stops at which point in the adrenal cortex?

Answer 6

Stops at androgen. Then in gonads the androgen is converted to estrogen and testosterone

Question 7

11 Beta hydroxylase catalyses which reaction?

Answer 7

Cortisone / deoxycortisol into hydrocortisone

Question 8

Where is CRH released from and where does it act on?

Answer 8

Released from hypothalamus and acts on anterior pituitary

Question 9

What is CRH

Answer 9

Corticotrophin releasing hormone

Question 10

When CRH acts on the anterior pituitary, what happens?

Answer 10

Adrenocorticotrophic hormone(ACTH) is released

Question 11

Where does ACTH bind to and what effect does it have?

Answer 11

Binds to adrenal cortex to stimulate the production of cortisol.

Question 12

How does ACTH regulate cortisol synthesis?

Answer 12

The conversion of cholesterol into pregnenolone is controlled by ACTH which is the first step in the synthesis pathway.
It does this by changing the gene expression of the enzyme in the cortex that catalyses this reaction

Question 13

ACTH has no effect on which region of the adrenal cortex?

Answer 13

Zona glomerulosa

Question 14

true or false, ACTH has no effect on cholesterol update and synthesis?

Answer 14

False. ACTH increases cholesterol uptake and synthesis

Question 15

What is the enzyme that converts cholesterol into pregnenolone?

Answer 15

Cholesterolesterase

Question 16

What impact does ACTH have on the cells of the adrenal cortex?

Answer 16

Because it is a trophic hormone, it increases the size and functionality and number of the cells. No ACTH = atrophy of adrenal gland

Question 17

Why is there a large surge of cortisol upon waking the morning?

Answer 17

Helps to mobilise your nutrients to use for energy after fasting for so long during sleep

Question 18

Is cortisol anabolic or catabolic?

Answer 18

Catabolic. Needs to breakdown muscle and fat to release protein (amino acids) into circulation

Question 19

Why is it so important to stabilise glucose levels during times of stress?

Answer 19

To fuel the brain, since it cannot store its own glycogen.

Question 20

List 2 potential causes of Cushing’s syndrome

Answer 20

ACTH secreting tumour
Adrenal tumour
Over medication of anti-inflammatory steroids

Question 21

List 3 Sx of Cushing’s syndrome

Answer 21

Poor healing / immunity
Thin skin and hair 
Body fat redistribution (buffalo hump, abdominal fat)
Protein depletion 
Insulin resistant diabetes

Question 22

The drug used to treat Cushing’s syndrome is?

Answer 22

Metyrapone

Question 23

Explain metyrapone MOA.

Answer 23

Inhibits 11-B hydroxylase which inhibits glucocorticoid synthesis

Question 24

Name 2 exogenous glucocorticoids

Answer 24

Prednisolone
Hydrocortisone
Budesonide

Question 25

Name an exogenous mineralcorticoid

Answer 25

Fludrocortisone

Question 26

Describe how aldosterone regulates fluid.

Answer 26

It promotes sodium retention (increasing reabsorption of water) and increases potassium excretion.

Question 27

How would low aldosterone cause death?

Answer 27

Thick blood due to too much water excretion would lead to circulatory shock.

Question 28

Addison’s disease, chronic failure of the adrenal cortex, is treated with what?

Answer 28

Exogenous glucocorticoids and mineralcorticoids

Question 29

Define HPA

Answer 29

Hypothamus-pituitary-adrenal axis

Question 30

The rate limiting step of the conversion pathway is...

Answer 30

ACTH

Question 31

Why are corticosteroids only produced as they are needed?

Answer 31

Because they cannot be stored in vesicles since they are too lipophillic

Question 32

List some examples of a stressful event that can trigger the release of cortisol

Answer 32

Exams, hypoglycaemia, starvation, infection, trauma, etc

Question 33

What are the two physiological regulatory mechanisms that stimulate cortisol release

Answer 33

``` Circadian rhythm (surge upon waking) Stress (stressful events throughout the day) ```

Question 34

Cortisol causes muscle anabolism. True or false.

Answer 34

False. Cortisol has a catabolic effect on muscles. Goal is to breakdown muscles to release amino acids which can be turned into glucose. Main role of cortisol is to stabilise glucose levels

Question 35

3 causes of Cushing’s syndrome

Answer 35

ACTH secreting tumour Adrenal tumour Over medication with steroid medications

Question 36

3 symptoms of Cushing’s syndrome?

Answer 36

- thin hair and skin - poor healing and immunity - body fat redistribution (buffalo hump)

Question 37

Compare hydrocortisone and prednisolone

Answer 37

Hydrocortisone is exogenous cortisol, and has the same receptor affinity, so it used as replacement therapy. Prednisolone has a high affinity for the anti-inflammatory receptor, so it used as an anti inflammatory.

Question 38

What stimulates the release of aldosterone

Answer 38

Low BP low ECF low sodium levels High potassium levels

Question 39

Role of aldosterone in kidneys?

Answer 39

Promote sodium retention (and therefore water retention) and increases potassium excretion.

Question 40

Short term and long term consequences of aldosterone deficiency?

Answer 40

Short = electrolyte imbalances and dehydration and hypotension Long term = circulatory shock

Question 41

Addison’s disease cause?

Answer 41

Autoimmune or chronic gland failure

Question 42

Addison’s disease treatment?

Answer 42

Replacement glucocorticoids (hydrocortisone) and mineralocorticoids (fludrocortisone)

Question 43

Which zone is the outermost and which is the innermost?

Answer 43

``` Outer = zona glomerulosa Middle = zona fasciculata Inner = zona reticularis ```

Question 44

First step of synthesis pathway for all steroid hormones?

Answer 44

Cholesterol to pregnenolone

Question 45

What is the purpose of cortisol breaking down muscles into amino acids?

Answer 45

Because the amino acids can be used in gluconeogenesis to create more glucose

Question 46

What is the purpose of cortisol inducing lipolysis?

Answer 46

Lipolysis breaks down far until fatty acids, that can be used as an alternative to glucose for energy. This spares glucose to be used in the brain

Question 47

Prolonged suppression of the HPA axis using glucorticoids can lead to what?

Answer 47

Irreversible atrophy of the adrenal gland (zona fasciculata)

Question 48

ACTH deficiency would NOT decrease the production of which hormone?

Answer 48

Aldosterone

Question 49

Define Addison’s disease

Answer 49

Adrenal hyposecretion.

Question 50

Sx of cortisol deficiency

Answer 50

Low blood glucose, poor response to stress

Question 51

Sx of aldosterone deficiency

Answer 51

Low BP, hyperkalemia (high Potassium which can affect cardiac rhythm) and hyponatremia (low sodium, which reduces ECF volume and therefore causes low BP)