Renata

Question 1

Suggest how body maintains a constant body temperature when in a cold environment

Answer 1

• receptors in the skin (hypothalamus)
• nerve impulses to hypothalamus)
• arterioles constrict (vasoconstriction) so less blood to skin
• idea that hair erector muscles contract to trap air (insulate)
• idea less heat loss by radiation, convection
• idea that heat generated by shivering/muscle contraction/increase in metabolic rate/increase in respiration
• idea less sweating/inhibition of sweat glands
• idea less heat loss by evaporation

Question 2

What is homeostasis?

Answer 2

The ability of the body to maintain a relatively constant internal environment necessary for life, regardless of changes in either external or internal conditions

Question 3

What steps are taken in our body to maintain suitable conditions for our body?

Answer 3

1) Change in the level of internal factor
2) Changes in the body detected by sensors ( receptors)
3) Message send to effector (works to reverse change-negative feedback or to increase it-positive feedback)

Question 4

Which 2 types of systems are used to detect change and respond?

Answer 4

• negative feedback system

- positive feedback system

Question 5

What is negative feedback?

Answer 5

Negative feedback is when levels change and feedback causes the opposite so that levels are restored. eg if blood glucose levels rise, insulin is released to lower it back down.

Question 6

What is positive feedback?

Answer 6

Positive feedback is when levels rise of a certain factor causes feedback making it rise more. An example is during the first part of menstrual cycle. Before ovulation, small amounts of oestrogen are secreted from the ovary.

Question 7

Give an example of homeostasis

Answer 7

thermoregulation