Lecture 30: Adrenal function Flashcards Preview

1060 Human form and function > Lecture 30: Adrenal function > Flashcards

Flashcards in Lecture 30: Adrenal function Deck (15):
1

what are the human endocrine organs and where are they positioned in the body??

2

Where is the adrenal gland?

3

which hormones are secreted from the adrenal gland??

4

Adrenal histology??

glomerulosa: small, close-packed cells (5-10%) 

fasiculata: larger cells in cords 75% 

reticularis: short cords of cells 

 

cells migrate and morphology and function changes 

5

where do steroid come from ??

cholesterol

6

section through a human adrenal 

7

Corticosteroid effects

Mineralocorticoid (eg aldosterone) 

major role is in control of electrolyte homeostasis

increases sodium reabsorption and potassium excretion in kidney

increases blood volume and pressure

regulated by renin-angiotensin system 

8

Corticosteroid effects

Glucocorticoid (eg cortisol)

major role is in response to “stress”

effects on metabolism to

- increase protein catabolism (in muscle)

- increase gluconeogenesis (in liver)

- increase plasma glucose 

cardiovascular system to

- influence blood flow and pressure 

inflammatory & immune systems  

- reduce inflammation
- suppress immune responses
- (this will decrease healing responses in the long term) 

9

Corticosteroid effects

Androgens (DHEA, androstenedione) 

may be involved in the development of secondary sexual characteristics at puberty

may have a role in preventing degenerative changes in ageing 

10

CONTROL OF ADRENAL FUNCTION

the renin-angiotensin system 

renin released by kidney nephrons in response to reduced plasma volume

renin converts angiotensinogen into angiotensin I

angiotensin 1 is converted to angiotensin II (ATII) in tissues

ATII binds to receptors on glomerulosa cells to stimulate aldosterone production

aldosterone increases Na+ reabsorption and so increases plasma volume 

11

CONTROL OF ADRENAL FUNCTION

the ACTH system 

ACTH released from anterior pituitary in response to stress

ACTH binds to receptors in faciculata and reticularis cells and stimulates cortisol production

cortisol affects metabolism (catabolic)

cortisol is anti-inflammatory

cortisol has an inhibitory feedback on the hypothalamus and pituitary 

12

Feedback control of anterior pituitary ?

13

ADRENAL DISORDERS ??

Deficiency

Deficiency: usually fatal if untreated

Congenital Adrenal Hyperplasia

enzyme deficiencies = no hormones

most serious (no cholesterol): no sexual differentiation

others (e.g. 11b hydroxylase): salt loss, hypertension, absent/precocious puberty 

 

Acquired Deficiency: Addison's disease

tuberculosis or autoimmune destruction

severe illness with hypotension, tiredness, weakness, anorexia, vomiting, depression

treated by steroid replacement 

14

ambiguous genitalia

“males” with ovaries 

15

ADRENAL DISORDERS 

Overproduction 

Overproduction 

Cushing’s syndrome

excess cortisol: too much CRH or ACTH (Cushing’s disease = pituitary tumour), or adrenal tumour, or clinical steroid administration 

abdominal obesity, redistribution of fat to the face and neck, red cheeks, bruising, glucose intolerant (diabetic), bone and muscle wasting (catabolism), hirsutism, mood changes 

treated by surgery (tumours) or pharmacology (enzymes) 

 

Mineralocorticoid

hypertension (headaches, vision blurring)

treated by aldosterone antagonist spironalactone