Homeostasis

Question 1

What is homeostasis?

Answer 1

Homeostasis is the maintenance of a relatively stable environment within the body e.g. body temperature

Question 2

Why is homeostasis important?

Answer 2

Homeostasis is important for normal cellular function

Question 3

What are feedback loops?

Answer 3

Homeostasis occurs via feedback loops. Feedback loops act upon specific variables. A feedback loop is activated when the variable is no longer in the normal range.

Question 4

What is a positive feedback loop and give an example.

Answer 4

Positive feedback loops move variables further away from the original set point and are likely to be used when a very rapid response is required e.g. blood clotting or labour

Question 5

What is a negative feedback loop and give an example.

Answer 5

Negative feedback loops return the variable to within its normal range e.g. body temperature.
Body temp. goes up/down (variable) - Thermoreceptors detect change (receptor) - feeds into hypothalamus of brain (control centre) - Sweat glands become more active (effector) - sweat on skin surface causes evaporative cooling and body temp. (original stimulus) is returned to normal range