B3.2.2 Negative Feedback

Question 1

What’s thyroxine

Answer 1

Hormone produced in thyroid gland

Important to regulate body’s metabolic rate

Question 2

Define metabolic rate

Answer 2

Speed at which the body transfers energy from its chemical stores in order to perform its functions

Question 3

What is adrenaline

Answer 3

Hormone secreted by adrenal glands in times of stress

Question 4

Outline steps of negative feedback

Answer 4

Conditions in body change from set point
Change detected by receptor
Corrective mechanisms activated by an effector
Conditions return to set point
Corrective mechanisms switched off

Question 5

How are thyroxine levels controlled when cold

Answer 5

Cold/stresssed (cells need more energy)
Hypothalamus detects that cells need more energy
Pituitary gland secretes TSH
thyroid releases thyroxine
Increase in metabolic rate
Normal energy level

Question 6

How are thyroxine levels controlled when hot

Answer 6

Too hot (too much energy)
Hypothalamus detects cells need less energy
Pituitary gland stops releasing TSH
a thyroid stops releasing thyroxine
Decrease metabolic rate
Normal energy levels

Question 7

How does body respond to adrenaline

Answer 7

Quicker respiration to increase ATP production
Increased breathing rate to cope with extra demand of oxygen
Increased heart rate to pump more blood to muscles
Diverting blood from areas like digestive system to the muscles that need it