Adrenal Gland

Question 1

Describe the structure of the adrenal gland

Answer 1

• zona glomerulosa (outer cortex)
• zona fasciculata (middle cortex)
• zona reticularis (inner cortex)
• adrenal medulla (centre of gland)

Question 2

What is the structure of the Zona glomerulosa ?

Answer 2

• cells arranged in clumps

Question 3

What is the structure of the Zona fasciculata ?

Answer 3

cells arranged in cords alongside the blood sinusoids

Question 4

What is the structure of the Zona reticularis ?

Answer 4

network of smaller cells

Question 5

What is the structure of the adrenal medulla ?

Answer 5

loose network of neurosecretory cells surrounded by blood vessels

Question 6

Function of the adrenal cortex

Answer 6

secretes 3 classes of steroid hormones
- glucocorticoids
- mineralocorticoids
- androgens

Question 7

function of the adrenal medulla

Answer 7

• part of the sympathetic nervous system
• produces catecholamines (adrenaline and noradrenaline

Question 8

What makes us the adrenal cortex ?

Answer 8

• Zona glomerulosa
• zona fasciculata
• zona reticularis

Question 9

What hormone is produced by the zona glomerulosa ?

Answer 9

mineralocorticoid (aldosterone)

Question 10

What hormone is produced by the zona fasciculata ?

Answer 10

glucocorticoid (cortisol)

Question 11

What hormone is produced by the zona reticularis ?

Answer 11

glucocorticoids & androgens

Question 12

What are external stimuli that affect the control of glucocorticoid secretion

Answer 12

• hypoxia
• hypoglycaemia
• stress

Question 13

What internal stimuli is involved in the control of glucocorticoid secretion ?

Answer 13

diurnal rhythms

Question 14

How is the secretion of glucocorticoid stimulated ?

Answer 14

• stimuli affects the hypothalamus
• hypothalamus releases corticotrophin-releasing hormone
• CRH acts on the pituitary gland
• pituitary releases ACTH
• ACTH acts on the adrenal cortex & triggers the release of glucocorticoids

Question 15

What effect does cortisol have on the immune system ?

Answer 15

immune suppression

Question 16

What effect does cortisol have on the liver ?

Answer 16

gluco-neogenesis

Question 17

What effect does cortisol have on muscle ?

Answer 17

protein catabolism

Question 18

What effect does cortisol have on adipose tissue ?

Answer 18

lipolysis

Question 19

What is another name for primary adrenal cortical hypofunction ?

Answer 19

Addison’s disease –> acute adrenal insufficiency

Question 21

What are some clinical features of Addison’s disease ?

Answer 21

lethargy, weakness, weight loss, anorexia, hypotension

Question 22

What causes Addison’s disease?

Answer 22

• 90% of cases are autoimmune
• remaining 10% can result from ; TB, tumour metastasis, amyloidosis, post adrenalectomy
• withdrawal of glucocorticoids

Question 23

What is the name of adrenal cortex hyper function the results in excess cortisol ?

Answer 23

Cushing’s syndrome

Question 24

What is the name of adrenal hyperfunciton with results in excess mineralocorticoid ?

Answer 24

Conn’s Syndrome

Question 25

What causes Conn’s Syndrome?

Answer 25

• adrenal adenoma = 75%
• bilateral hyperplasia of zona glomerulosa
• adrenal carcinoma

Question 26

What are some clinical features of Conn’s syndrome?

Answer 26

hypertension, muscle weakness, tetany, paresthesia

Question 27

Define tetany

Answer 27

muscle spasms

Question 28

Define Paresthesia

Answer 28

abnormal sensation –> tingling or prickling

Question 29

What are some clinical features of Cushing’s syndrome ?

Answer 29

• moon face
• proximal muscle wasting
• purple striae
• slow healing wounds

Question 30

What can cause Cushing’s disease ?

Answer 30

• antieror pituitary tumour creating excess ATCH –> Excess glucocorticoid released
• Adrenal carcinoma or adenoma
• ectopic ACTH - usually produced by a tumour located elsewhere
• iatrogenic cushings = too much glucocorticoids being taken (medication)

Question 31

What are Catecholamines?

Answer 31

adrenaline and noradrenaline

Question 32

What do catecholamines influence ?

Answer 32

• BP
• cardiac output
• fuel metabolism
• sweating
• pupil size

Question 33

What are the metabolic effects of adrenaline ?

Answer 33

• increase glycogen breakdown
• gluconeogenesis
• lipolysis
• increase release of amino acids, lactate & pyruvate

Question 34

What is Pheochromocytoma ?

Answer 34

• adrenal medulla hyperfunction
• catecholamine secreting tumour

Question 35

What are some clinical features of pheochromocytoma ?

Answer 35

• hypertension
• vasomotor signs

Question 36

What are vasomotor signs ?

Answer 36

anxiety, sweating, palpitations, tremors and abdominal pain