B3.2.2 Flashcards
What does thyroxine do
Regulates the body’s metabolic rate
What does the thyroid gland do
The thyroid gland takes iodine in and converts it into thryoxine.
What does adrenaline do
Prepares the body for intensive action
Negative feedback what is it used for
Negative feedback is an important type of control used in homeostasis.
What is negative feedback
1) Conditions in body change from a point
2) A change detected by receptors
3) Corrective mechanisms activated by an effector
4) Conditions returns to set point
5) Corrective mechanisms switched off
What is the change detected by
The change is detected by sensory receptors. Effectors work to reverse the change and restore conditions to their base levels.
How are thyroxine levels controlled
When the body requires more energy. Hypothalamus releases TRH causing the pituitary gland to release TSH (thyroid stimulating hormone), stimulates thyroid gland to release thyroxine. Increases metabolic rate allowing cells to transfer additional energy. As thyroxine levels increase TRH and TSH is inhibited
What happens when the cells have the required amount of energy
When cells have the required amount of energy, hypothalamus inhibits production of TSH. Thyroid gland stops releasing thyroxine.
How are adrenaline levels controlled
Adrenaline levels are controlled by the same process
When you feel threatened or scared
Respire quicker -> increases ATP production
Increases rate of breathing to cope with extra demand for oxygen
Increasing heart rate
Diverts energy away from digestive system towards the muscles
When stress is removed, signals to glands stop. Therefore the glands stop producing adrenaline.
