HUBS 191 Lecture 28

Question 1

where are the adrenal glands

Answer 1

on top of the right and left kidneys

Question 2

what are the components of the adrenal glands

Answer 2

the capsule - provides protection
the cortex
the medulla

Question 3

what are the 3 layers of the adrenal cortex

Answer 3

zona glomerulosa
zona fasciculata
zona reticularis

Question 4

what is the adrenal capsule made of

Answer 4

connective tissue

Question 5

what is the function of the zona glomerulosa

Answer 5

produces aldosterone (mineralocorticoid) which increases sodium reabsorption in kidney and potassium excretion. aldosterone secretion is stimulated by angiotensin 2 and high potassium

Question 6

what is the function of the zona fasiculata

Answer 6

secreters glucocorticoids (e.g. cortisol) which is involved in glucose metabolism

Question 7

what is the function of the zone reticularis

Answer 7

secretes adrenal androgens (and estrogen). it also plays a role in fetal development and pre-puberal development with mild affects in females after puberty.

Question 8

what is the function of the adrenal medulla

Answer 8

it secretes adrenaline and noradrenaline which are involved in the SNS

Question 9

in the adrenal medulla axon terminals release ACh into _____ on ____ cells

Answer 9

nicotinic acetylcholine receptors (nAChRs) - chromaffin

Question 10

what does the release of ACh in the adrenal medulla lead to

Answer 10

depolarisation and therefore the release of adrenaline

Question 11

what type of cell secretes adrenaline and noradrenaline into the blood stream

Answer 11

chromaffin

Question 12

adrenaline and noradrenaline affect all cells with the correct receptors - what are these receptors called

Answer 12

Alpha and beta adrenergic receptors

Question 13

the type of response to adrenaline/noradrenaline depends on

Answer 13

the hormone released
which receptors are present the cell
the type of cell

Question 14

generally adrenaline/noradrenaline will produce effects associated with promoting

Answer 14

immediate survival in threatening situations

Question 15

what effect do adrenaline/noradrenaline have in adipose tissue

Answer 15

fat breakdown to produce energy

Question 16

what effect do adrenaline/noradrenaline have in the muscle and liver

Answer 16

glycogen breakdown. glycogen is a storage molecule that can be broken down into glucose.

Question 17

what is a pheochromocytoma

Answer 17

a rare benign tumour of the adrenal medulla derived from chromaffin cells which results in an increase in secretion of adrenaline and noradrenaline

Question 18

what is corticotropin releasing hormone (CRH)

Answer 18

a peptide hormone released by hypothalamic neurons which acts on the anterior pituitary causing it to secrete ACTH in a diurnal pattern

Question 19

factors increasing CRH secretion include

Answer 19

physical stress or trauma
hypoglycaemia
emotional stress
infection

Question 20

what is ACTH and where is it produced

Answer 20

a peptide hormone produced by corticotrophin - cells of the anterior pituitary

Question 21

what are the effects of ACTH

Answer 21

it acts on the zona fasiculata and zona reticularis to produce glucocorticoids and sex hormones

Question 22

how does ACTH release glucocorticoids and sex hormones

Answer 22

it binds with G-coupled protein receptors in the adrenal cortex. ACTH increases cortisol and adrenal androgen synthesis by increasing expression/activity of steriodogenic enzymes

Question 23

adernocorotical hormones are bound to plasma proteins in the blood. for example

Answer 23

cortisol binding globulin or albumin

Question 24

what do glucocorticoids help resist

Answer 24

physiological stress

Question 25

how do glucocorticoids help resist physiological stress

Answer 25

they increase responsiveness to catecholamines (so they help maintain BP) increased glycogenesis in the liver mobilises amino acids from extra hepatic tissue especially muscle promotes mobilisation of lipids from fat means more glucose available for the brain

Question 26

what is aldosterone secreted in response to

Answer 26

activation of the renin-angiotestin system high ECF potassium low ECF sodium

Question 27

how does aldosterone act in the body

Answer 27

in acts on nephrons in the kidney to increase reabsorption of sodium increases renal excretion of potassium in urine can also promote reabsorption of sodium by epithelial cells of sweat, salivary glands and in the intestines

Question 28

how does sodium level affect BP

Answer 28

sodium in the main ECF cation and a major determinant of ECF volume and therefore BP

Question 29

what is Cushing syndrome caused by

Answer 29

an excess of glucocorticoids which may result from administration of exogenous corticosteroids or tumours

Question 30

what is adrenal neoplasia

Answer 30

a growth in the adrenal glands - either an adenoma (benign) or carcinoma (malignant)

Question 31

what is addisons disease

Answer 31

a primary adrenal insufficiency with causes including autoimmune disease, TB and metastatic cancer

Question 32

what are some longer term responses to stress (not caused by adrenaline/noradrenaline)

Answer 32

breakdown of proteins and fats to provide substrate for liver to produce new glucose (gluconeogenesis) switch in metabolism of many tissues to using lipids as an energy source which leave glucose available for the brain increased BGL conservation of sodium and water but loss of potassium

Question 33

what are symptoms of the exhaustion phase

Answer 33

energy reserves have finally been depleted the structural integrity of the tissues is compromised inability to maintain acceptable BGL failure to maintain adequate fluid and electrolyte balance cardiovascular damage due to prolonged elevation in blood volume, BP, BGL etc.

Question 34

what does the inability to maintain acceptable BGL lead to

Answer 34

hypoglycaemia in starvation insulin resistance in chronic mental or emotional stress