4.4: The adrenal gland

Question 1

Location of adrenal glands

Answer 1

Located on top of the kidneys
Right adrenal gland is just below the liver which pushes the right kidney down (lower than left)

Question 2

Difference between arteries and veins in the adrenal glands

Answer 2

Many arteries but each adrenal gland has only one vein each (L/R Adrenal vein)

Question 3

Where does the left adrenal vein drain blood into

Answer 3

Renal vein

Question 4

Where does the right adrenal vein drain blood into

Answer 4

Inferior vena cava

Question 5

3 zones making up adrenal cortex (surrounding the adrenal gland and adrenal medulla)

Answer 5

Reticularis
Zona fasciculata
Zona glomerulosa

Question 6

Two segments of the adrenal gland

Answer 6

Adrenal medulla (central)
Adrenal cortex

Question 7

The adrenal medulla secretes

Answer 7

Catecholamines:
-adrenaline
-noradrenaline (dopamine)

Question 8

The adrenal cortex secretes

Answer 8

Corticosteroids:
-mineralocorticoids (aldosterone)
-glucocorticoids (cortisol)
-sex steroids (androgens, oestrogens)

Question 9

What is a steroid

Answer 9

Derivatives of cholesterol (… can be absorbed by mouth)

Question 10

Precursor of adrenal gland

Answer 10

Cholesterol

Question 11

How many C atoms does a cholesterol molecule contain

Answer 11

27 carbon atoms
4 benzene rings

Question 12

What is an enzyme

Answer 12

Protein that catalyses a specific reaction to modify molecules

Question 13

What enzymes are most commonly absent in conditions of the adrenal gland

Answer 13

21 hydroxylase
17 hydroxylase

Question 14

Function of aldosterone

Answer 14

Control of blood pressure, control of Na+/K+(lowered)

Question 15

Aldosterone mechanism of action

Answer 15

Stimulates Na+ reabsorbtion in distal convoluted tubule and collecting duct
Stimulates K+ and H+ secretion
Resulting in Increased sodium reabsorption, increased water reabsorption, raising blood volume and lowering blood pressure

Question 16

How is aldosterone regulated

Answer 16

As blood pressure falls Renin is secreted

Question 17

Mode of action of Renin

Answer 17

Decreased renal perfusion pressure (associated with decreased arterial BP)
Increased renal sympathetic activity
Decreased Na+ load to top off loop of Henle

Question 18

Renin stimulates the activation of

Answer 18

Angiotensin II

Question 19

Effects of angiotensin II on the adrenals

Answer 19

Activation of enzymes ->side chain cleavage
3 hydroxysteroid dehydrogenase
21
11
18 hydroxylase

Question 20

How does renin increase blood pressure

Answer 20

Renin causes side chain cleavage
As cholesterol passes through the enzyme pathway
Hormones present push out aldosterone
Therefore retaining NA+

Question 21

4 physiological effects of cortisol

Answer 21

Normal stress response
Metabolic effects
Weak mineralocorticoid effects
Renal and cardiovascular effects

Question 22

What metabolic effects does cortisol have

Answer 22

Peripheral protein catabolism
Hepatic gluconeogenesis
Increased blood glucose concentration
Fat metabolism
Enhanced effects of glucagon and catecholamines

Question 23

Renal and cardiovascular effects of cortisol

Answer 23

Excretion of water load
Increased vascular permeability

Question 24

What hormone regulates cortisol secretion

Answer 24

ACH

Question 25

Hypothalamic pituitary adrenal axis

Answer 25

Hypothalamus releases corticotrophin releasing hormone to the pituitary gland Which secretes adreno-corticotrophic hormone to the adrenal glands These stimulate the release of cortisol Which in turn forms a negative feedback loop to the pituitary gland and hypothalamus

Question 26

What kind of rhythm does cortisol release have

Answer 26

Diurnal rhythm Low at night high in the morning

Question 27

What type of disease is Addisons disease

Answer 27

Autoimmune disease targeting adrenal cortex TB of adrenal glands -Primary adrenal failure-

Question 28

What occurs during Addisons disease

Answer 28

Pituitary starts secreting lots of ACTH (peptide) and therefore MSH (melanocyte-stimulating hormone)

Question 29

Symptoms of Addison’s disease 3

Answer 29

Increased pigmentation Autoimmune vitiligo No cortisol or aldosterone so low blood pressure

Question 30

Why do patients with Addison’s disease appear to have a tan?

Answer 30

POMC is a large precursor protein cleaved to form ACHT and MSH High levels of ACHT can result in tanned skin Therefore creating a positive feedback loop

Question 31

Course of Addisons disease

Answer 31

Cortisol deficiency Aldosterone deficiency Salt loss Low blood pressure Eventual death

Question 32

Urgent treatment of Addisonian crisis

Answer 32

Rehydrate with normal saline Give dexterous to prevent hypoglycaemia - may be due to glucocorticoid deficiency Give hydrocortisone (glucocorticoid)

Question 33

What happens if you have too much cortisol

Answer 33

Your metabolism changes put on weight blood pressure increases Can lead to Cushing syndrome

Question 34

What can cause too much cortisol

Answer 34

Tumour of adrenal -> excess cortisol Tumour of pituitary-> excess ACTH

Question 35

Clinical signs of Cushing syndrome

Answer 35

Moon face Red cheeks Easy bruising Red striae Pendulous abdomen Poor wound healing Proximal myopathy Impaired glucose tolerance - diabetes, hypertension, osteoporosis Thin skin Fat pads Red cheeks Mental changes

Question 36

Cushing syndrome occurs due to

Answer 36

Excess of cortisol or other glucocorticoid

Question 37

4 possible causes of Cushing syndrome

Answer 37

Taking steroids by mouth (common) Pituitary dependent Cushing disease Ectopic ACTH Adrenal adenoma or carcinoma

Question 38

Catecholamines are derived from

Answer 38

The medulla - ectodermal neural crest

Question 39

Function of catecholamines

Answer 39

Precursors for Adrenaline and noradrenaline synthesis = tyrosine

Question 40

Where are catecholamines stored

Answer 40

In cytoplasmic granules and released in response to ACH from preganglionic symoathetic neurones

Question 41

Involvemet of catecholamines in

Answer 41

Fight or flight response

Question 42

NA and Adr circulate bound to

Answer 42

Albumin

Question 43

What two hepatic enzymes degrade catecholamines

Answer 43

Monoamine oxidase Catechol-O-methyl