Thyroid/Parathyroid 1

Question 1

Feedback loops: (+)

Answer 1

Increase in one action triggers an increase in target

Question 2

Feedback loops: (-)

Answer 2

Response in a target is opposite to the perturbation

Question 3

Example of a positive feedback loop (oxytocin)

Answer 3

Childbirth contractions trigger oxytocin, which in turn amplifies the contractions

Question 4

T3 =

Answer 4

Triiodothyronine

Question 5

T4 =

Answer 5

Throxine

Question 6

What are the thyroid hormones?

Answer 6

T3
T4
Calcitonin

Question 7

Overall, what do T3 and T4 do?

Answer 7

• Regulate metabolic rate of body

- Increase protein synthesis

Question 8

T3 and T4: How do they work in the cell and how does this account for the genetic component in thyroid disease?

Answer 8

• Enter cell and bind with receptors in nucleus

- DNA stimulated for gene expression (this is why there’s a genetic component in thyroid disease)

Question 9

T3 and T4 are necessary for

Answer 9

normal growth and development

• esp brain and bone!

Question 10

T3 and T4 stimulate and enhance the effects of ____, accounting for impacts on brain and bone development

Answer 10

GH

Question 11

Thyroid hormones: calcitonin has a weak effect on:

Answer 11

calcium-phosphorus balance

Question 12

Thyroid function is regulated by:

Answer 12

• hypothalamus and pituitary feedback controls

- SOME intrinsic regulation by the gland itself

Question 13

How does thyroid function impact metabolism, growth, and development?

Answer 13

• increased thermogenesis
• cardiovascular effects
• metabolic effects

Question 14

How does thyroid function impact thermogenesis

Answer 14

affects BMR and heat production

Question 15

How does thyroid function impact the cardiovascular system?

Answer 15

• increases HR and contractility

- possibly by enhancing effect of epi and norepi

Question 16

How does thyroid function impact metabolism?

Answer 16

energy substrate utilization

• Glucose absorption and enzyme enhancement
• Lipolysis and lipolytic hormone use

Question 17

When the thyroid gland is stimulated, where do the hormones go and what do they do?

Answer 17

• travel from thyroid via bloodstream to nearly all body tissues
• Activate genes that regulate body functions

Question 18

Negative feedback loop control of thyroid function

Answer 18

• When hypothalamus senses that circulating levels have dropped, it signals the pituitary gland
• Pituitary sends TSH to the thyroid to trigger release of thyroid hormones