glands - adrenal

Question 1

location of adrenal glands

Answer 1

A pair of glands found superior to each of the kidneys

Right = below the liver and behind IVC

Left = medial to spleen and lateral to aorta

Question 2

general function of adrenal glands

Answer 2

Site of steroid and catecholamine hormone production and secretion

Question 3

gross structure of an adrenal gland

Answer 3

Outer cortex and inner medulla

Leaving vessels (veins and lymphatics) do so via the hilum

Arteries and nerves enter at numerous sites

Question 4

blood supply

Answer 4

Blood Supply:

Superior adrenal - from inferior phrenic

Middle adrenal - from aorta

Inferior adrenal - from renal arteries

Question 5

venous draining

Answer 5

Venous Drainage:

Right adrenal vein > IVC

Left adrenal vein > left renal vein

Question 6

innervation of adrenal glands

Answer 6

Innervation:

Coeliac plexus

Greater splanchnic nerves

(to medulla, sympathetic innervation via myelinated presynaptic fibers is from T10 - L1)

Question 7

cortex histology

Answer 7

Cortex is made up of sheets of cells surrounded by capillaries
Cortex is split into 3 histological zones (superficial to deep)

Zona glomerulosa (most superficial)
Zona fasciculata
Zona reticularis (most deep)

Question 8

medulla histology

Answer 8

Medulla is made up of chromaffin cells that contain granules storing hormones

Question 9

what 3 hormones does the cortex synthesise?

Answer 9

steroid hormones

1. cortisol
2. aldosterone
3. androgens

Question 10

what dos the adrenal medulla secrete?

Answer 10

catcholamines

1. noradrenaline
2. adrenaline
3. dopamine

Question 11

what is synthesised in the zone glomerulosa?

Answer 11

Aldosterone (zona glomerulosa)

Part of the renin-angiotensin-aldosterone system

= works to stimulate reabsorption of sodium and retain sodium in salivary glands and sweat glands

acts on intracellular mineralocorticoid receptors

Question 12

what is secreted from the zone fasciculata?

Answer 12

Cortisol (zona fasciculata)

Prolonged stress hormone

Preserves glucose for the brain

Works at intracellular glucocorticoid receptors

Question 13

what is secreted from the zona reticularis

Answer 13

androgens

Question 14

what is the role of catecholamines?

Answer 14

activate the sympathetic nervous system by binding to adrenergic receptors

Question 15

what is the embryonic origin of the medulla and cortex?

Answer 15

medulla = ectoderm (think ectoderm is skin and CNS - catecholamines work on the nervous system)

cortex = mesoderm

Question 16

how does the adrenal medulla develop?

Answer 16

Adrenal medulla:

Originates from ectoderm

Develops from the sympathetic ganglion that is derived from neural crest cells ( in an essay you can talk about how the neural crest cells are formed)

A mass is formed medial to the fetal cortex

Question 17

how does the adrenal cortex develop?

Answer 17

Adrenal cortex:
Derived from mesoderm

Develops from the epithelium of the posterior abdominal wall that covers the coelmic cavity

6th week: aggregation of mesenchymal cells between dorsal mesentary and developing gonads

Further divided into 2 layers at birth (zona glomerulosa, fasiculata)

After 3 years of age, the cortex further differentiates into a 3rd layer (zona reticularis)

Question 18

clinical

Answer 18

cushings syndrome = excess cortisol (when you’re stressed you need a cushion)

pituitary adenoma causes excess ACTH = excess cortisol
OR excess cortisol prescribed

= could cause diabetes mellitus, fatty deposits at the back of the neck, depression

Question 19

clinical - hyperaldosteronism

Answer 19

primary = too much angiotensin secreted

secondary = too much activation of the R-A-A (e.g. blockage to kidneys that reduces perfusion)

= water and sodium retention (high BP and osmolarity)
= excess potassium secretion (hypOkalaemia)

spironolactone is an aldosterone antagonist