Adrenal Glands

Question 1

Where are adrenal glands

Answer 1

Above kidneys

Question 2

How many arteries and veins does each adrenal gland have

Answer 2

Lots of arteries but only one vein each

Question 3

Where do the left and right adrenal veins drain into?

Answer 3

Left adrenal vein drains into renal vein which drains into IVC
right adrenal vein drains into IVC(inferior vena cava)

Question 4

What are the three layers of the adrenal cortex

Answer 4

Zona Glomerulosa

Zona Fasiculata

Zona Reticularis

Question 5

What hormone class is produced by the adrenal cortex?

Answer 5

Corticosteroids

Question 6

What hormone does each of the adrenal cortex layers produce?

Answer 6

Zona glomerulosa - Mineralocorticoids (Aldosterone)

Zona Fasiculata - Glucocorticoids (Cortisol)

Zona Reticularis - Sex Steroids (Androgens, Oestrogens)

Question 7

How is Progesterone formed from Cholesterol?

Answer 7

Side chain cleavage of cholesterol to produce Pregnenolone

3 beta Hydroxy Steroid Dehydrogenase acts on Pregnenolone to produce Progesterone

Question 8

How is Aldosterone produced from Progesterone?

Answer 8

21 Hydroxylase acts on Progesterone (by adding OH) to produce 11 Deoxycorticosterone

11 Hydroxylase acts on 11 Deoxycorticosterone to produce Corticosterone

18 Hydroxylase acts on Corticosterone to produce Aldosterone

Question 9

How is Cortisol produced from Progesterone?

Answer 9

17 hydroxylase adds OH group to carbon 17 of progesterone to form 17 hydroxy-progesterone

21 hydroxylase adds OH group to carbon 21 to form 11 deoxy-cortisol

11 hydroxylase adds OH group to carbon 11 to form cortisol

Question 10

What hormone class is made by adrenal medulla

Answer 10

Catecholamines (produced by neuroendocrine/chromaffin cells of the medulla)
Eg - Adrenaline aka epinephrine (80%)
- Noradrenaline aka norepinephrine (20%)
- Dopamine

Question 11

Where are catecholamines stored and how are they released

Answer 11

• Stored in cytoplasmic granules
• Released in response to ACh from preganglionic sympathetic neurones

Question 12

Role of catecholamines

Answer 12

Fight or flight response e.g. tachycardia, sweating, increased blood glucose, alertness, vasoconstriction

Question 13

What are adrenaline and noradrenaline bound to when circulating in bloodstream

Answer 13

Albumin

Question 14

What two hepatic enzymes degrade them

Answer 14

Monoamine oxidase
Catechol o methyl transferase

Question 15

Precursor amino acid for adrenaline and noradrenaline

Answer 15

Tyrosine

Question 16

Where is adrenal medulla derived from

Answer 16

Ectodermal neural crest

Question 17

Aldosterone

Answer 17

Major net effect is to conserve body sodium by stimulating its reabsorption

Aldosterone enters cells of Distal Convoluted Tubule (DCT) via bloodstream and increases expression of Na+ transporters (on apical) and Na+/K+ pumps (on basolateral)

Which helps you reabsorb sodium and lose potassium (cells K+ is pumped out into urine)

Na+/K+ pump transports this Na+ into the bloodstream and water with it due to lower water potential in the blood

This increases blood volume and pressure (so ultimately aldosterone controls blood pressure)

Question 18

How is aldosterone regulated

Answer 18

• In kidney, the juxtaglomerular apparatus is always monitoring blood pressure
• When there’s decreased renal perfusion pressure (associated with low BP), this leads to increased renal sympathetic activity to JGA cells, the JGA cells release renin into blood
• Renin converts angoiotensinogen (protein made in the liver) into Angiotensin I
• Then angiotensin converting enzyme (ACE) converts Angiotensin I into Angiotensin II
• Angiotensin II increases Aldosterone production by increasing the activation of the enzymes needed to convert Cholesterol into Aldosterone, (ang II also has other effects like vasoconstriction)

ACE made in lungs

Question 19

What are the physiological effects of Cortisol with regards to metabolic, immune and vascular effects?

Answer 19

Metabolic - Increases blood glucose conc. by hepatic gluconeogenesis, lipolysis, proteolysis, and decreased cellular insulin sensitivity

Immune - Decreased intensity of immune inflammatory response

Vascular - Excretion of water load and increased vascular permeability

Question 20

How is cortisol secretion regulated

Answer 20

CRH produced in hypothalamus stimulates release of ACTH in the anterior pituitary gland

ACTH stimulates production of Cortisol in adrenal gland

Increased cortisol means less ACTH and CRH secreted from hypothalamus and anterior pituitary and vice versa (in a negative feedback system)

Question 21

What rhythm does cortisol have

Answer 21

when you wake up it’s at its highest

Question 22

Addison disease

Answer 22

• Primary adrenal failure happens
• Autoimmune disease where immune system destroys adrenal cortex→ cortisol and aldosterone deficiency
• Salt loss
• TB of the adrenal glands is the commonest cause worldwide
• Primary starts secreting lots of ACTH and hence MSH

Question 23

Symptoms of Addison

Answer 23

Hyperpigmentation(tanned skin) due to - POMC (pro-opio-melanocortin) is a large precursor protein that is cleaved to form a number of smaller peptides including ACTH, MSH and endorphins
- People who have pathologically high levels of ACTH will also have high MSH levels and may become tanned
- MSH stands for melanocyte-stimulating hormone

Low blood which leads to death as they have no cortisol or aldosterone
Adrenal crises
Nausea
Weight loss
Weakness

Question 24

Treatment of Addison as

Answer 24

Saline
Dextrose to prevent hypoglycemia
Hydrocortisone

Question 25

Cushing syndrome

Answer 25

Excess cortisol or glucocorticoid
Caused by taking steroids orally,pituitary adenoma where lots of ACTH is made,ectopic ACTH secretion (lung cancer cells randomly make ACTH),adrenal adenoma

Question 26

Symptoms of Cushing

Answer 26

Striae (stretch marks) as protein can’t be made fast enough to facilitate weight gain and fat deposits
Centripetal obesity
Poor wound healing and easy bruising
Fat pads on neck
Thin skin
Diabetes
Moon face
Weakness of upper limbs