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B5: Quiz 9 – Answers
B5: Quiz 9 – Answers
1)
a) Adrenaline
b) The adrenal glands that are located at the top of the kidneys
c) Any 3 from:
2)
a) Thyroxine is produced by the thyroid gland, which is found in the neck
b) BMR stands for basal metabolic rate. BMR is the rate at which chemical reactions happen in the body whilst the body is at rest
c) High
d)
i) Thyroid stimulating hormone (TSH)
ii) Pituitary gland, which is found at the base of the brain
iii) Lots (a greater quantity of TSH will result in lots of thyroxine being secreted into the bloodstream by the thyroid gland)
3)
a) At point A, the level of thyroxine in blood is too high. When thyroxine levels in blood are too high, the pituitary gland will stop secreting TSH (TSH secretion is inhibited). A lower level of TSH in blood causes the thyroid gland to secrete less thyroxine into the bloodstream, which results in blood thyroxine levels decreasing back to their normal/ optimal level.
b) At point B, the level of thyroxine in blood is too low. When thyroxine levels in blood are too low, the pituitary gland will secrete more TSH into the bloodstream. A greater level of TSH in blood causes the thyroid gland to secrete more thyroxine into the bloodstream, which results in blood thyroxine levels increasing back to their normal/ optimal level.
4) An underactive thyroid gland will not secrete enough thyroxine into the bloodstream. This causes their blood thyroxine levels to be lower than they should be, which results in them having a lower BMR. As their BMR is lower, less glucose is broken down during respiration reactions, which means that the glucose is stored as fat instead. This can result in individuals with underactive thyroid glands gaining weight.
a) Adrenaline
b) The adrenal glands that are located at the top of the kidneys
c) Any 3 from:
- Heart rate and blood pressure increases
- Breathing rate and volume of air per breath increases
- The liver breaks down glycogen into glucose
- Your eyes dilate slightly
2)
a) Thyroxine is produced by the thyroid gland, which is found in the neck
b) BMR stands for basal metabolic rate. BMR is the rate at which chemical reactions happen in the body whilst the body is at rest
c) High
d)
i) Thyroid stimulating hormone (TSH)
ii) Pituitary gland, which is found at the base of the brain
iii) Lots (a greater quantity of TSH will result in lots of thyroxine being secreted into the bloodstream by the thyroid gland)
3)
a) At point A, the level of thyroxine in blood is too high. When thyroxine levels in blood are too high, the pituitary gland will stop secreting TSH (TSH secretion is inhibited). A lower level of TSH in blood causes the thyroid gland to secrete less thyroxine into the bloodstream, which results in blood thyroxine levels decreasing back to their normal/ optimal level.
b) At point B, the level of thyroxine in blood is too low. When thyroxine levels in blood are too low, the pituitary gland will secrete more TSH into the bloodstream. A greater level of TSH in blood causes the thyroid gland to secrete more thyroxine into the bloodstream, which results in blood thyroxine levels increasing back to their normal/ optimal level.
4) An underactive thyroid gland will not secrete enough thyroxine into the bloodstream. This causes their blood thyroxine levels to be lower than they should be, which results in them having a lower BMR. As their BMR is lower, less glucose is broken down during respiration reactions, which means that the glucose is stored as fat instead. This can result in individuals with underactive thyroid glands gaining weight.
Questions
1)
a) What is the name of the hormone that is known as the fight or flight hormone?
b) What is the name of the glands that secrete the hormone in part a, and where are they located?
c) Give 3 effects that the secretion of the hormone in part a has on the human body.
2)
a) What gland produces thyroxine and where is this gland found?
b) Thyroxine controls BMR. What does BMR stand for and what does it mean?
c) If there is lots of thyroxine in blood, will BMR be low or high?
d) There is another hormone that controls how much thyroxine is produced.
i) What is the name of this hormone?
ii) What gland in the body secretes this hormone and where is this gland found?
iii) Will a greater quantity of this hormone in blood result in lots of thyroxine being secreted or very little thyroxine being secreted?
3) The graph below shows how the level of thyroxine in blood changes over time.
1)
a) What is the name of the hormone that is known as the fight or flight hormone?
b) What is the name of the glands that secrete the hormone in part a, and where are they located?
c) Give 3 effects that the secretion of the hormone in part a has on the human body.
2)
a) What gland produces thyroxine and where is this gland found?
b) Thyroxine controls BMR. What does BMR stand for and what does it mean?
c) If there is lots of thyroxine in blood, will BMR be low or high?
d) There is another hormone that controls how much thyroxine is produced.
i) What is the name of this hormone?
ii) What gland in the body secretes this hormone and where is this gland found?
iii) Will a greater quantity of this hormone in blood result in lots of thyroxine being secreted or very little thyroxine being secreted?
3) The graph below shows how the level of thyroxine in blood changes over time.
a) Explain what happens at point A to bring the levels of thyroxine in blood back to the normal/ optimal level.
b) Explain what happens at point B to bring the levels of thyroxine in blood back to the normal/ optimal level.
4) Explain how an underactive thyroid gland can cause an individual to gain weight.
b) Explain what happens at point B to bring the levels of thyroxine in blood back to the normal/ optimal level.
4) Explain how an underactive thyroid gland can cause an individual to gain weight.