The Adrenal Gland

Question 1

Where does the left adrenal vein drain into?

Answer 1

Renal vien (57 arteries)

Question 2

Where does the right adrenal vein drain into?

Answer 2

IVC (inferior vena cava)

Question 3

How many arteries and veins do the adrenals have?

Answer 3

Both adrenal have many arteries many arteries but only one vein

Question 4

What is the zona glomerulosa?

Answer 4

Outer most thin layer and se of enzymes that make aldosterone

Question 5

What is the zona fasciulata?

Answer 5

Enzymes which make cortisol

Question 6

What does the adrenal medulla do?

Answer 6

Make adrenaline (secretes catecholamines)

Question 7

What does the adrenal cortex make?

Answer 7

• corticosteroids
  1. Mineralocorticoids (Aldosterone)
  2. Glucocorticoids (Cortisol)
  3. Sex steroids (Androgens, oestrogens)

Question 8

What does the adrenal medulla (neuroedncorine/chromaffin cells)?

Answer 8

• catecholamines
  1. Adrenaline/epinephrine (80%)
  2. Noradrenaline/norepinephrine (20%)
  3. [Dopamine]

Question 9

What does zona reticularis make?

Answer 9

Cortisol (androgens and eostrogens and works with zona fasciluatris) (not really mostly middle zone)

Question 10

Where do steroid come from?

Answer 10

Cholesterol (27C atom)

Question 11

What is the adrenal gland secretion precursor?

Answer 11

Cholesterol

Question 12

What is an enzyme?

Answer 12

1. Protein that catalyses a specific reaction
2. Various enzymes are present in cells
3. Specific enzymes catalyse the synthesis of particular alterations to the molecule

Question 13

What is the synthesis of aldosterone?

Answer 13

1. Cholesterol
2. Side chain cleavage
3. Left with pregneolone
4. Then enzyme 3 beta hydroxy steroid dehyrogenase (oxidation Zoe)
5. Progesterone
6. Enzyme: 21 hyroxylase
7. 11 deoxycorticosterone
8. 11 hydroylase
9. Corticosterone
   10, 18 hydroxylase
10. Aldosterone (control blood pressure )

Question 14

What is synthesis of

Answer 14

1. Cholesterol
2. Side chain cleavage
3. Left with pregneolone
4. Then enzyme 3 beta hydroxy steroid dehyrogenase (oxidation Zoe)
5. Progesterone
6. 17 hydroxylase
7. 17 hydroxy progesterone
8. 21 hydroxylase
9. 11 deoxy cortisol
10. 11 hydroxylase
11. Cortisol

Question 15

What does aldosterone do?

Answer 15

1. Stimulates Na+ reabsorption in distal convoluted tubule and cortical collecting duct in kidney (and in sweat glands, gastric glands, colon)
2. Stimulates K+ and H+ secretion, also in distal convoluted tubule and cortical collecting duct
   -Major net effect is to conserve body sodium by stimulating its reabsorption
   -Increased sodium reabsorption water reabsorption,
   raising blood volume

Question 16

How is aldosterone regulated?

Answer 16

• If BP low more Renin made
• Decreased renal perfusion pressure (normally associated with decreased arterial BP)
• Increased renal sympathetic activity (direct to JGA cells)
• Decreased Na+ load to top of loop of Henle (macula densa cells)

Question 17

How does renin work?

Answer 17

1. Renin comes out of kidney
2. Enzymes? convert angiotesingen (from liver) to angiotensin 1
3. This is then covered to angiotensin 2 by enzyme ACE
4. This stimulates vasoconstriction and directly tells adrenal gland to make aldosterone in zona glomerusa

Question 18

How does angiotensin 2 make aldosterone?

Answer 18

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

Question 19

What is a summary of what aldosterone? does?

Answer 19

Controls blood pressure, controls sodium retention and lowers potassium

Question 20

So what happens if you are stabbed or suddenly BP falls?

Answer 20

1. Make renin
2. Renin stimulates proaction of angiotensin 2
3. This turns on these enzymes in adrenal gland to make aldosterone rapidly
4. Therefore train sodium and so do not die from fall of BP

Question 21

What are the metabolic effects of cortisol?

Answer 21

• peripheral protein catabolism
• hepatic gluconeogenesis
• increased blood glucose concentration
• fat metabolism (lipolysis in adipose tissue)
• enhanced effects of glucagon and catecholamines

Question 22

What are the renal and cardiovascular effects of cortisol?

Answer 22

• excretion of water load

* increased vascular permeability

Question 23

What are other physiological effects of cortisol?

Answer 23

• Normal stress response

- Weak mineralocorticoid effects

Question 24

How is cortisol regulated ?

Answer 24

• ACTH (hormone) from pituitary gland
• Cortisol puts two steps of negative feedback so if too much will suppress ACTH in pituitary gland and precursor of ACTH (CRH) in the hypothalamus
• Negative feedback via circulation

Question 25

What is the effect of ACTH on the adrenals?

Answer 25

``` Activation of the following enzymes Side Chain Cleavage 3 Hydroxysteroid dehydrogenase 21 hydroxylase 11 hydroxylase 18 hydroxylase ```

Question 26

What is the rhythm of cortisol?

Answer 26

- Diurnal - Up at 5am and peak 8:30 then goes down - Circadian rhythm

Question 27

What is Addisons disease?

Answer 27

- Thomas Addison (18th century) 1. Primary adrenal failure 2. Autoimmune disease where the immune system decides to destroy the adrenal cortex (UK) 3. Tuberculosis of the adrenal glands (commonest cause worldwide) 4. Pituitary starts secreting lots of ACTH and hence MSH

Question 28

Why do patients with Addisons disease have a good tan?

Answer 28

- POMC is a large precursor protein that is cleaved to form a number of smaller peptides, including ACTH, MSH and endorphins - Thus people who have pathologically high levels of ACTH may become tanned

Question 29

What is the urgent treatment of addinosian crisis?

Answer 29

1. Rehydrate with normal saline 2. Give dextrose to prevent hypoglycaemia which could be due to the glucocorticoid deficiency 3. Give hydrocortisone or another glucocorticoid

Question 30

What happens during Addions disease?

Answer 30

1. Increased pigmentation 2. Autoimmune vitiligo may coexist 3. No cortisol or aldosterone, so low blood pressure

Question 31

What is a summary of Addions disease?

Answer 31

* Cortisol deficiency * Aldosterone deficiency * Salt loss * Low blood pressure * Eventual death

Question 32

What is Cushing;s syndrome?

Answer 32

- Too much cortisol: metabolism changes and put on weight - Can cause too much cortisol` tumour of adrenal: excess cortisol, tumour of pituitary: excess ACTH - Occurs due to an excess of cortisol or other glucocorticoid

Question 33

What are the clinical signs of Cushing's syndrome?

Answer 33

* Thin skin * Proximal myopathy * Centripetal obesity (lemon on sticks) * Diabetes, hypertension and osteoporosis * Immunosuppression (reactivation of TB) * Moon face * Striae

Question 34

What are the dour possible causes of Cushings syndrome?

Answer 34

1. Taking steroids by mouth (common) 2. Pituitary dependent Cushing's disease (pituitary adenoma) 3. Ectopic ACTH (lung cancer) 4. Adrenal adenoma or carcinoma

Question 35

What are catecholamines?

Answer 35

- Medulla derived from ectodermal neural crest - Precursor for Adr & NA synthesis = tyrosine - Catecholamines stored in cytoplasmic granules & released in response to ACh from preganglionic sympathetic neurones

Question 36

What is the role of catecholamines?

Answer 36

- ‘Fight or flight response’ e.g. tachycardia, sweating, increased blood glucose, alertness, vasoconstriction - NA & Adr circulate bound to albumin - Degraded by two hepatic enzymes: monoamine oxidase & catechol-O-methyl transferase