Test # 4 Thyroid hormones

Question 1

Where is TSH made

Answer 1

pituitary gland in brain

Question 2

Where is the TSH located

Answer 2

on the plasma membrane

Question 3

the TRH is made by

Answer 3

the hypothalamus

Question 4

describe the process of how the actual thyroid hormone is made

Answer 4

• The Hypothalamus is signaled to release TRH onto the pituitary gland.
• This will cause the TSH to be released from the pituitary
• the TSH will then act on the thyroid gland to release T4 which then goes to the tissues

Question 5

What can feedback to the hypothalamus to decrease the production of TRH if there is too much in the pituitary

Answer 5

TSH - this is called short loop

brain (Pituitary) feeding back to brain (hypothalamus) to stop/decrease the release of TRH which decreases TSH production!

Question 6

What is the auto feedback mechanism that explains when the target organ (the organ that gets the T4 from the thyroid) gets too much T4 is sends a signal back to the brain (hypothalamus) to decrease the production of TRH?

Answer 6

Long loop - target organ feedback to brain

Question 7

What disease is when you have low levels of TSH and high levels of T3/T4?

Answer 7

hyperthyroidism - Graves disease

Question 8

What disease is when you have high levels of TSH and low levels of T3/T4?

Answer 8

hypothyroidism - Hashimoto’s

Question 9

What kind of receptors do T3/T4 bind to?

Answer 9

Nuclear receptors

they bind in the nucleus of the cells and active the gene expression on the DNA

Question 10

What is the process called?
if we didn’t have thyroid hormones NOREPI would be useless because. TH promotes gene transcription and some of these are B adrenergic receptor genes - so no hormone = low level of adrenergic receptors. Norepi would not be effective

Answer 10

Premissiveness

Question 11

What potentates the adrenergic system

Answer 11

TH

Question 12

What is absolutely required for perinatal brain development - if low levels then it causes____

Answer 12

T3

low levels cause Cretinism (mentally retarded)

Question 13

What autoimmune disease does it not help to lower TSH levels because there is a formation of antibodies that binds to the TSH receptor and activates them

Answer 13

Graves disease

Question 14

A drug to treat hyperthyroidism.
It blocks the transport of iodine
found in foods and cigarettes
Jim Jones effect - drank “kool-aid” and killed everyone

Answer 14

Thiocyanate

Question 15

A drug to treat hyperthyroidism.
It blocks the transport of iodine
10x more active than thiocyanate

Answer 15

Perchlorate

excessive doses (2-3g/day) can cause fatal aplastic anemia

Question 16

What two drugs tx for hyperthyroid but cross placenta (class D - no pregnant pt)
- they can be used but one more than the other\_\_\_\_. Dr. would make sure if it is worth the risk to the fetus

Answer 16

Propylthiuoracil (PTU) and Methimazole

Question 17

What causes a decrease in thyroxin production at the organification step to stop the production of TH. It decreases the BMR within hours

Answer 17

Iodine

Question 18

What drug to tx hyperthyroidism leads to partial destruction of the thyroid gland

Answer 18

131I - Radioactive iodine

Question 19

What drug used to tx hyperthyroidism blocks type 1 deiodinase

Answer 19

propylthiouracil

Question 20

What drug used to tx hyperthyroidism blocks type 1 and type 2 deiodinase

These drugs also release 75-150mg of iodine which helps inhibit t3/t4 secretion (used as radiology contract dyes)

Answer 20

Sodium ipodate

iopanoic acid

Question 21

What is a life threatening event which causes exaggerate sympt of hyperthyroidism
(high fever, tachy, n/v, AHF

What is the #1 and #2 treatment plans
and then give what last?

Answer 21

Thyroid Storm

#1: BB to decrease HR
#2: antipyretics - to decrease fever
Then give PTU to block the conversion of T4 to T3

Question 22

What autoimmune disorder is caused by a gene defect that does not allow the conversion of T4 to T3 then to TH

Low T4/T3 and high TSH

Answer 22

Hypothyroidism

Question 23

upper eyelid lowering

fluid accumulation of fluid around neck (not a tumor)

Answer 23

ptosis

goiter

Question 24

What is it called when you have marked retardation in growth, severe MR, and poor nervous system development in infancy

Answer 24

Cretins

Question 25

What two hormones can be given to help treat hypothyroidism?

Answer 25

Levothyroxine Sodium (T3 - Synthroid)

Lyothronine Sodium (T4)

Question 26

How is the efficacy monitored when giving 
Levothyroxine Sodium (T3 - Synthroid) and 
Lyothronine Sodium (T4)

Answer 26

Serum TSH levels - if the therapy is working then the TSH levels will start to decrease becauseT4 and T3 stimulate TSH