Adrenaline and Thyroxine

Question 1

What is adrenaline?

Answer 1

-a hormone released by the adrenal glands released in response to stressful or scary situations
-the brain detects fear or stress and sends nervous impulses to the adrenal glands which respond by sending adrenaline

Question 2

what is the purpouse of adrenaline?

Answer 2

it prepares the body for a ‘flight or fight’ by triggering mechanisms that increase the supply of oxygen and glucose to cells in the brain and muscles e.g. adrenaline increases heart rate

Question 3

what gland secretes thyroxine?

Answer 3

the thyroid gland in the neck

Question 4

what is the role of thyroxine?

Answer 4

it plays an important role in regulating the basal metabolic rate- the speed at which chemical reactions in the body occur while the body is at rest
-it is also important for lots of processes in the body such as stimulating protein synthesis for growth and development

Question 5

when is thyroxine released into the body?

Answer 5

it is released in response to a thyroid stimulating hormone which is released in the pituitary gland

Question 6

How is the level of thyroxine in the blood controlled and kept at the right level?

Answer 6

-by negative feedback
-when the level of thyroxine in the blood is higher than normal the secretion of TSH from the pituitary gland is inhibited
-this reduces the amount of thyroxine released from the thyroid gland so the level falls back to normal