Adrenal Gland

Question 1

Where are the adrenal glands?

Answer 1

Sitting above the kidneys, hidden at the back of the abdomen and protected by the ribs

Question 2

Describe the blood supply of the adrenal glands

Answer 2

Many adrenal arteries

One adrenal vein

Question 3

Where do the veins of the adrenal glands drain in to?

Draw it w/ adrenal glands, blood supply and surrounding organs

Answer 3

Right - straight into the inferior vena cava
Left - into the renal vein which then connects to the IVC
(Include liver, spleen, aorta, IVC, arteries, veins, kidneys (left slightly higher) + adrenal glands)

Question 4

Name the layers of the adrenal glands (out to in)

Draw it

Answer 4

Capsule
Adrenal cortex:
-Zona glomerulosa
-Zona fasciculata
-Zona reticularis 
Adrenal Medulla

Question 5

What hormones do the Adrenal medulla make?

Answer 5

Catecholamines:
Adrenaline 80%
Noradrenaline 20%

Question 6

What hormones do the Adrenal cortex make?

Answer 6

Mineralocoericoids/Aldosterone (made in zona glomerulosa)
Glucocorticoids/Cortisol (made in zona fasciculata)
Sex steroids/Androgen+Oestrogen (made in zona reticularis)

Question 7

What is a steroid

Answer 7

Comes from a cholesterol

Question 8

Purpose of cholesterol + draw structure w/ carbon numbers

Answer 8

Acts as a precursor for hormones produced in adrenal gland secretions

Question 9

How to make aldosterone from cholesterol?

In glomerulosa

Answer 9

Initial side chain cleavage producing pregnenolone
3 beta hydroxy steroid dehydrogenase hydroxylates OH group to form progesterone
Glomerulosa:
21 hydroxylase -> 11 deoxycorticosterone
11 hydroxylase -> Corticosterone
18 hydroxylase -> Aldosterone/ Mineralocorticoid

Question 10

How to make glucocorticoid form cholesterol?

In fasciculata

Answer 10

Initial side chain cleavage producing pregnenolone
3 beta hydroxy steroid dehydrogenase hydroxylates OH group to form progesterone
Fasciculata:
17 hydoxylase -> 17 hydroxy-progesterone
21 hydoxylase -> 11 deoxy-cortisol
11 hydoxylase -> Cortisol/ Glucocorticoid

Question 11

What does aldosterone do?

Answer 11

Aldosterone maintains blood pressure
It stimulating Na+ reabsorption, water reabsorption raising blood volume, in distil convoluted tubule and cortical collecting duct in kidney (+ sweat glands, gastric glands, colon)
Also stimulates K+ and H+ secretion in tubules and ducts which is then removed in urine
Major net effect is to conserve body sodium by stimulating its reabsorption, control blood absorption and lower K+

Question 12

How is it aldosterone regulated?

Answer 12

Juxtaglomerular apparatus continually measures BP
if low BP is detected renin (made in kidney) is released, if high BP is detected renin is suppressed
Decreased renal perfusion pressure (decreased arterial BP)
Increased renal sympathetic activity (directed to Juxtaglomerular apparatus)
Decreased Na+ load to top of loop of Henle (macula densa cells)

Question 13

Renin’s Stimulation

Answer 13

Liver makes Angiotensinogen protein which is converted to Angiotensin I by renin hormone. Angiotensin I is converted into Angiotensin II by ACE (angiotensin converting enzyme). Angiotensin II regulates aldosterone release, turning on 3 enzymes in adrenal gland. Zona glomerulosa pushes out aldosterone which retains sodium and reverse fall in BP.

Question 14

Effects of angiotensin II on adrenals

Answer 14

Activation of enzymes:
3 hydroxysteroid dehydrogenase
21 hydroxylase
11 hydroxylase
18 hydroxylase 
and is involved in side chain cleavage

Question 15

Physiological effects of cortisol

Answer 15

Normal stress response 
Weak minealocorticoid effects
Renal + Cardiovascular Effects:
excretion of water load
increased vascular permeability
Metabolic effects:
Peripheral protein catabolism 
Hepatic gluconeogenesis
Increased blood glucose concentration 
Fat metabolism 
Enhanced effects of glucagon and catecholamines

Question 16

Describe Adenohypophysis negative feedback

Answer 16

Cortisol levels cause negative feedback mechanism in which either hypothalamus or pituitary gland is stimulated to alter CRH levels which in turn affects ACTH levels and controls cortisol levels. Cycle continues when levels are too high or low.

Question 17

HPA axis

Answer 17

Negative feedback drawing where increased cortisol causing decrease in CRH levels in hypothalamus and ACTH levels from the pituitary gland altogether decreasing the amount of cortisol produced in the adrenal gland.

Question 18

Effects of ACTH on the adrenal glands

Answer 18

Activation of enzymes:
3 Hydroxysteroid dehydrogenase 
21 hydroxylase
11 hydroxylase
17 hydroxylase
and side chain cleavage

Question 19

Rhythm due to cortisol

Answer 19

Circadian rhythm

Question 20

Addison’s disease

Answer 20

Primary adrenal failure
Autoimmune disease where the immune system decides to destroy the adrenal cortex
Tuberculosis of the adrenal glands
Pituitary starts secreting lots of ACTH and MSH (causes pigmentation) as they are co-released

Question 21

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

Answer 21

Pro-opio-melanocortin (POMC) large precursors protein that is cleaved to form a number of smaller peptides including ACTH , MSH and endorphins
High MSH levels cause a tan
Thus people who have pathologically high levels of ACTH may become tanned

Question 22

Addison’s disease causes……

Answer 22

Cortisol deficiency
Aldosterone deficiency 
Salt loss
Low blood pressure
Eventual death

Question 23

Urgent treatment of Addisonian crisis

Answer 23

Rehydrate w/ normal saline
Give dextrose to prevent hypoglycaemia which could be due to the glucocorticoid deficiency
Give hydrocortisone or another glucocorticoid (cortisol/ prednisolone)

Question 24

What happens if you have too much cortisol?

Answer 24

Metabolism changes and put on weight

Retaining too much energy and metabolism changes when you put on fat as you lose protein and convert it into fat

Question 25

What can cause too much cortisol?

Answer 25

Benign Tumour in adrenal (excess cortisol) or tumour in pituitary (excess ACTH) which causes pressure to release more of the hormones

Question 26

Cushing’s syndrome

Answer 26

Tumour causes increase of ACTH and so excess cortisol which then causes
Fat production and stops making proteins
Easy bruising thin skin
Diabetes, hypertension and osteoporosis
Immunosuppression
Mental changes
Red stria as skin tears due to lack of proteins to cope with fat build up
High Na+ so increased blood pressure
Poor healing

Question 27

Possible causes of Cushing’s syndrome

Answer 27

Occurs due to excess of cortisol or other glucocorticoid
So:
Taking steroids by mouth for a long time
Pituitary dependent Cushing’s disease (pituitary adenomas)
Ecptopic ACTH (lung cancer)
Adrenal adenomas or carcinoma

Question 28

What are Catecholamines?

Answer 28

Made by adrenal medulla derived from ectoderm album neural crest
Precursor forAdrenaline (80%) and Noradrenaline (20%) synthesis (using tyrosine)
Tyrosine converted to Dopa (using O2), (remove CO2) to Dopamine which can be secreted very rapidly and is really important.
Dopamine (OH removed) producing Noradrenaline, (+ CH3) to produce Adrenaline
Catecholamines stored in cytoplasmic granules and release in response to Ach preganglionic sympthatetic neurones

Question 29

Role of catecholamines

Answer 29

Fight or flight response:
Tachycardia, sweating, increased blood glucose, alertness, vasoconstriction

NA and ADR circulate bound to albumin
Degraded by two hepatic enzymes:
Monoamine oxidase and catecholamines-O-methyl transferase