5.4.2 adrenal glands

Question 1

adrenal cortex

Answer 1

outer layer of adrenal gland

Question 2

adrenal gland

Answer 2

one of pair of glands lying above kidneys, which release adrenaline & number of other hormones known as corticoids (corticosteroids) eg. aldosterone

Question 3

adrenaline

Answer 3

hormone released from adrenal glands, which stimulates body to prepare for fight or flight

Question 4

adrenal medulla

Answer 4

inner layer of adrenal gland

Question 5

where are adrenal glands found

Answer 5

anterior to kidneys

Question 6

what are adrenal glands divided into

Answer 6

• outer adrenal cortex
• inner adrenal medulla

Question 7

3 layers of adrenal cortex

Answer 7

1. zona glomerulosa
2. zona fasciculata
3. zona reticularis

Question 8

describe the zona glomerulosa

Answer 8

• outermost layer
• secretes mineralocorticoids eg. aldosterone

Question 9

describe the zona fasciculata

Answer 9

• middle layer
• secretes glucocorticoids eg. cortisol

Question 10

describe the zona reticularis

Answer 10

• innermost layer
• secretes precursor molecules used to make sex hormones

Question 11

what does adrenal medulla secrete

Answer 11

adrenaline & noradrenaline

Question 12

action of steroid hormones

Answer 12

1. steroid hormone passes through cell surface membrane of target cell
2. steroid hormone binds to specific receptor (complementary shape) in cytoplasm
3. receptor-steroid hormone complex enters nucleus of target cell & binds to another specific receptor on chromosomal material
4. binding stimulates production of mRNA, which codes for production of proteins

Question 13

name some hormones produced by adrenal cortex

Answer 13

• mineralocorticoids
• glucocorticoids
• cortisol

Question 14

describe role of mineralocorticoids in body eg. aldosterone

Answer 14

eg. aldosterone
- from zona glomerulosa
- help control conc. of sodium & potassium in blood
- help maintain blood pressure
- aldosterone = acts on cells of distal tubules & collecting ducts in kidney which increases absorption of sodium ions, decreases absorption of potassium ions & increases water retention (increasing BP)

Question 15

describe role of glucocorticoids in body eg. cortisol

Answer 15

eg. cortisol
- from zona fasciculata
- help control metabolism of carbs, fats & proteins in liver
- cortisol released in response to stress/result of low blood glucose conc. & stimulates production of glucose from stored compounds (eg. glycogen, fats & proteins) in liver

Question 16

describe role of cortisol in body

Answer 16

• from zona reticularis
• if correct enzymes aren’t present for release, the zona reticularis releases precursor androgens into blood = taken up by ovaries/testes & converted to sex hormones
• sex hormones help development of secondary sexual characteristics & regulate production of gametes

Question 17

describe adrenaline

Answer 17

• polar molecule derived from tyrosine (amino acid)
• can’t enter cells via plasma membrane
• must be detected by specialised receptors on plasma membrane of target cells
• many cells/tissues have adrenaline receptors = effects of adrenaline widespread

Question 18

examples of effects of adrenaline on body

Answer 18

• relaxing smooth muscle in bronchioles
• increase stroke volume of heart
• increase heart rate
• general vasoconstriction = raise blood pressure
• stimulating conversion of glycogen to glucose
• dilate pupils
• increase mental awareness
• inhibiting action of gut
• body hair stand erect