B11.4 The role of negative feedback

Question 1

What is the negative feedback system?

Answer 1

Involves coordination of changes in the internal environment of your body with the amounts of hormone produced

Question 2

What happens if an initial change happens?

Answer 2

Negative feedback - the response causes the opposite

Question 3

What is the purpose of the thyroid gland?

Answer 3

Uses iodine from your diet to produce the hormone thyroxine - controls the basal metabolic rate of your body

Question 4

What is the metabolic rate?

Answer 4

How quickly substances are broken down and built up

A sum of all the reactions in your body

Question 5

What happens if the level of thyroxine falls in your body?

Answer 5

Detected by sensors in the brain - as a result the amount of TSH released from the pituitary gland increases

Question 6

What does TSH stand for?

Answer 6

Thyroid-stimulating hormone

Question 7

What happens if you are: stressed - angry or excited?

Answer 7

Your adrenal glands located above the kidneys secret lots of adrenaline that is carried around by the bloodstream affecting lots of organs?

Question 8

What does Adrenaline cause?

Answer 8

Heart rate and breathing rate to increase
Stored glycogen in the liver to be converted to glucose for respiration
Pupils of your eyes to dialate to let in more light
Mental awareness to increase
Blood to be diverted away from your digestive system to he big muscles of the limbs

Question 9

How does a negative feedback system work?

Answer 9

If a factor in the internal environment increases
changes take place to reduce it and restore the original level.
If a factor in the internal environment decreases
changes take place to increase it and restore the original level.

Question 10

What are the differences between thyroxine and adrenaline?

Answer 10

Thyroxine involves a negative feedback loop whilst adrenaline doesn’t
Thyroxine controls metabolic rate in adults and growth in children
Adrenaline increases heart rate etc..