Coordination and Response

Question 1

What is homeostasis?

Answer 1

Homeostasis is the maintenance of a constant internal environment
eg body temperature, blood glucose level, water content

Question 2

What are receptors?

Answer 2

Receptors detect external stimuli

Eg eyes detect changes in light

Question 3

What are effectors?

Answer 3

Effectors are cells that bring about a response to stimuli

eg muscle cells

Question 4

What is a stimulus?

Answer 4

Any change in the internal or external environment

Question 5

What is negative feedback?

Answer 5

The process by which the body corrects any movement away from the optimum internal conditions.
A change in environment is detected, signalled to other cells and responded to to reverse it

Question 6

What are hormones?

Answer 6

Chemical messengers
Released into the blood
Slow acting and long lasting

Question 7

What is the normal blood glucose level?

Answer 7

90mg/100cm3 of blood

Question 8

What is insulin and what does it do?

Answer 8

Hormone produced by pancreas
Helps control blood sugar levels
Levels too high -> pancreas secretes more insulin -> more glucose is changed to glycogen -> normal levels

Question 9

What is ADH and what does it do?

Answer 9

Anti-diuretic hormone
Released by pituitary gland
Makes collecting ducts of nephrons more permeable so more water is reabsorbed
Water loss -> more ADH released -> kidney reabsorbs more water -> hydrated

Question 10

What is vasodilation?

Answer 10

When blood vessels close to the skin’s surface widen.

Increases blood flow, so more thermal energy transfer to surroundings, cooling you down.

Question 11

What is vasoconstriction?

Answer 11

When blood vessels close to the skin’s surface narrow/constrict.
Reduces blood flow, so less thermal energy transfer to surroundings.

Question 12

What does skin do when you’re too hot?

Answer 12

Produces sweat, which evaporates transferring energy to surroundings
Vasodilation
Hairs lie flat

Question 13

What does skin do when you’re too cold?

Answer 13

Produces very little sweat
Vasoconstriction
Hairs stand on end to trap insulating layer of air

Question 14

What is adrenaline and what does it do?

Answer 14

Secreted by adrenal glands
Makes heart beat faster, so muscle cells receive more glucose and oxygen for respiration
Prepares for ‘fight or flight’

Question 15

What is testosterone and what does it do?

Answer 15

Hormone produced by the testes
Main male reproductive hormone and stimulates sperm production
Controls secondary sexual characteristics, eg facial hair

Question 16

What is oestrogen and what does it do?

Answer 16

Hormone produced by the ovaries
Repairs, thickens and maintains the uterus lining. stimulates LH release, stops FSH production
Controls secondary sexual characteristics, eg breast development

Question 17

What is progesterone and what does it do?

Answer 17

Hormone secreted by ovaries

Maintains the lining of the uterus during the middle part of the menstrual cycle and during pregnancy.

Question 18

What is LH (lutenising hormone) and what does it do?

Answer 18

Hormone secreted by pituitary gland
Stimulates ovulation (egg release) in females and testosterone production in males

Question 19

What is FSH (follicle stimulating hormone) and what does it do?

Answer 19

Secreted by pituitary gland

Stimulates egg development in ovary and oestrogen secretion in females and sperm production in males

Question 20

What is the placenta?

Answer 20

Organ responsible for providing oxygen and nutrients to fetus and removing waste substances
Mother and fetus’s blood do not mix, substances diffuse

Question 21

What does amniotic fluid do?

Answer 21

Acts as a shock absorber, protecting the fetus