Hormones and Homeostasis

Question 1

Define the term hormone; give two examples

Answer 1

A chemical messenger that moves to target organs in the blood plasma, e.g. adrenaline, ADH, oestrogen, testosterone, FSH, LH etc.

Question 2

Describe the role of insulin after a meal

Answer 2

Insulin released from pancreas; stimulates conversion of glucose to glycogen (stored in muscle/liver); blood sugar level decreases

Question 3

Describe the role of adrenaline in the body

Answer 3

Released from adrenal glands; increases heart rate and breathing rate; stimulates conversion of glycogen to glucose; diverts blood flow to muscles and away from digestive system; dilates pupils; increases clarity of thinking etc.

Question 4

Describe the role of testosterone

Answer 4

Released from testes; stimulates development of secondary sexual characteristics in males

Question 5

Describe the role of oestrogen

Answer 5

Released from ovaries; stimulates development of secondary sexual characteristics in females; repairs uterus lining after menstruation

Question 6

Describe the role of progesterone

Answer 6

Released from ovaries; maintains lining of uterus during pregnancy

Question 7

What common structure releases ADH, FSH and LH?

Answer 7

Pituitary gland

Question 8

Define the term homeostasis

Answer 8

Maintenance of a constant internal environment

Question 9

Give two examples of homeostasis in the human body

Answer 9

Control of body water levels, control of core body temperature, control of blood glucose levels

Question 10

Describe what is meant by the term vasodilation

Answer 10

Arterioles near the surface of the skin widen; more blood flows near the surface of the skin; more heat lost by radiation

Question 11

Describe what is meant by the term vasoconstriction

Answer 11

Arterioles near the surface of the skin narrow; less blood flows near the surface of the skin; less heat lost by radiation

Question 12

Describe two ways, other than vasodilation, that cool the body down when too hot

Answer 12

Sweating (evaporation of water from surface of skin); hairs lie flat (less heat trapped)

Question 13

Describe two ways, other than vasoconstriction, that keep the body warm when too cold

Answer 13

Shivering (rapid muscle contractions to release heat by respiration); hairs stand on end (trap more heat)

Question 14

What part of the brain detects changes in body temperature and water levels?

Answer 14

Hypothalamus