14.1 Hormonal Communication

Question 1

What is a hormone?

Answer 1

Chemical messenger

transported by bloodstream

secreted by gland

Question 2

What is an endocrine gland?

Answer 2

group of cells

specialised to secrete hormones

Question 3

What is the function of the pineal gland?

Answer 3

produces melatonin

affects reproductive development & daily cycles

Question 4

What is the function of the thymus gland?

Answer 4

produces thymosin

promoted production & maturation of white blood cells

Question 5

What is the function of the adrenal gland?

Answer 5

produces adrenaline

increases heart rate, breathing rate & blood glucose level

Question 6

What hormones are released by the ovaries?

Answer 6

oestrogen - develops lining

progesterone - maintains lining

Question 7

What hormones are produced by the pituitary gland?

Answer 7

growth hormone, ADH, gonadotrophins

Question 8

What is the function of the thyroid gland?

Answer 8

produces thyroxine

controls rate of metabolism & rate of glucose respiration

Question 9

What is a steroid hormone?

Answer 9

Hormone which is lipid-soluble

so can pass through membranes

Question 10

What is a non-steroid hormone?

Answer 10

Hormone which is non-lipid soluble/hydrophilic

cannot pass through membranes

Question 11

How do steroid hormones function?

Answer 11

steroid hormone passes through lipid component of plasma membrane

binds to specific receptors (either in cytoplasm or nucleus)

hormone-receptor complex acts as transcription factor

inhibits/facilitates transcription of specific gene

Question 12

How do non-steroid hormones function?

Answer 12

cannot pass through plasma membrane since hydrophilic & non-lipid soluble

bind to specific receptors on plasma membrane (non inside cell)

triggers cascade of reactions, mediated by second messengers

Question 13

Compare the way in which hormonal & nervous system function:

Answer 13

HORMONAL:

uses chemical hormones

travel in bloodstream

slow to bring about response/slow transmission

responses are long-lasting

response is widespread

effect may be irreversible

travel to all parts of body, but only target organs respond

NERVOUS:

uses electrical impulses & chemical neurotransmitter

travels by neurones

fast to bring about response/fast transmission

response is short-lived

response is localised

effects usually reversible

travels to specific parts of the body

Question 14

What is the structure of the adrenal glands?

Answer 14

ADRENAL CORTEX - produces vital hormones, aldosterone + cortisol

ADRENAL MEDULLA - produces non-essential hormones, adrenaline

Question 15

What are the 3 main types of hormones released by the adrenal cortex?

Answer 15

GLUCOCORTICOIDS

MINERALOCORTICOIDS

ANDROGENS

Question 16

What is the role of glucocorticoids?

Answer 16

regulate METABOLISM - control how body converts fats/carbohydrates/proteins to energy

regulate BLOOD PRESSURE

regulate IMMUNE RESPONSE + SUPPRESS INFLAMMATORY reactions

release of glucocorticoids controlled by hypothalamus

Question 17

What is the role of mineralocorticoids?

Answer 17

controls BLOOD PRESSURE - maintains balance between salt + water concentrations in blood + bodily fluids

release of mineralocorticoids mediated by kidney

Question 18

What is the role of androgens?

Answer 18

releases small amounts of male + female sex hormones

Question 19

Which hormones are released by the adrenal medulla?

Answer 19

ADRENALINE - increases heart rate, raises blood glucose levels etc

NORADRENALINE - narrows blood vessels to non-esential organs