Hormones And Metabolic Rate Flashcards
What is metabolic rate?
The rate at which the energy stores in your food is transferred by all the reaction that take place in your body to keep you alive
What do the adrenal glands release
Adrenalin
When might Adrenalin be secreted?
During frightening or exciting situations, due to an increase in impulses from neurones reaching the adrenal glands. From the spinal cord
What is adrenalin’s effect on the heart?
Heart cells contract more RAPIDLY (increase heart rate) and MORE STRONGLY (increase blood pressure)
What is Adrenalins effect on the liver?
Cells change from glycogen to glucose quicker
More glucose is released into the blood, increasing blood sugar concentration
How does Adrenalin affect blood vessels?
Leading to targeted muscles - blood vessels widen, increasing blood flow to those targeted muscles
Other organ’s blood vessels - narrow reducing blood flow and increasing blood pressure
What is negative feedback
a control mechanism that reacts to a change on a condition by trying to bring the condition down to a normal level
Explain how changes caused by Adrenalin prepare the body for ‘Fight or flight’
By increasing blood flow to targeted organ + with heart rate increasing, the body can act quickly on whether to run away from danger or fight it
- Increased heart rate, blood pressure, blood sugar levels and blood flow also cause this ‘fight or flight’ instinct
Describe the negative feedback diagram for thyroxine
Hypothalamus ⬇️ TRH Pituitary gland ⬇️ TSH Thyroid gland ⬇️Thyroxine Other target organs
How does thyroxine control metabolic rate as a negative feedback?
- Low levels of thyroxine stimulates the production of TRH in the hypothalamus
- This causes the release of TSH from the pituitary gland
- TSH acts on the thyroid to produce thyroxine
- When thyroxine levels aren’t normal, thyroxine inhibits the release of TRH and the production of TSH
- This keeps the metabolic rate steady
