Deck 63: The Thyroid Gland

Question 1

Iod ine en ter s f ollic ula r c ells

A) By primary active transport
B) By secondary active transport using Na+ to driv e up hill transp ort
C) Pa ss ive ly
D) Bound to tyrosine
E) Bound to thyronine

Answer 1

B

Question 2

The m ain ac tive for m of t hyr oid ho rm on e in the tiss ue s is

A) T3
B) T4
C) Reverse T3
D) DIT
E) MIT

Answer 2

A

Question 3

A patient has low levels of T3 and T4. You test for TSH and find it is elevated. You conclude that

A) Iodine deficiency is the cause of low T3 and T4 levels
B) En d- or ga n u nr es po ns ive ne ss to T SH ca us ed the low T 3 a nd T 4 le ve ls
C) The patient has normal hypothalamic-pituitary function
D) The thyroid gland can't concentrate iodine
E) T he pro ble m lies in o rg an ific atio n o f th e th yro glo bu lin

Answer 3

C

Question 4

Which of the following is an example of primary hypothyroidism?

A) Defects in the TRH receptor
B) Defec ts in TSH s tructure
C) T ra um atic les ion of t he hyp op hys ea l sta lk
D) Defects in TRH secretion
E) Lack of iodine in the diet

Question 5

The m ain ne ga tive fee db ac k o n T SH se cr etio n is pro vid ed by

A) TRH
B) Body tem perature
C) T4 and T3 levels in the blood
D) Sex steroids
E) TBG from the liver

Question 6

The thyroid gland is located

A) In the neck on both sides of the trachea
B) Just above the kidney
C) In the region between stomach and sm all intestine
D) Buried within the parathyroid gland
E) At the angle of the jaw next to the lymph nodes

Question 7

The m ech anis m of ac tion of T3 is to

A) Phosphorylate discrete sets of proteins
B) Regulate the insertion of proteins into cell mem branes
C) Selectively regulate degradation of certain proteins
D) Regulate gene expression through binding of thyroid receptors to thyroid response eleme nts
E) R eg ula te g en e e xp re ss ion thr ou gh JA K- ST AT pa thw ays

Question 8

Iod ine us ed for thyr ox ine syn the sis

A) Co m es a lm os t exc lusiv ely fro m foo d o r iod ized salt
B) Derives from body fat stores
C) Comes mostly from drinks
D) C om es fro m the air
E) None of the above

Question 9

In iodine deficiency

A) TSH Increases due to decreased negative feedback by T3
B) TSH Increases due to stress
C) TSH Increases due to LATS
D) T3 levels are unaffected because iodine is recycled from DIT and MIT and so TSH is normal
E) TSH decreases due to CNS depression

Question 10

The thyroid follicle contains

A) Thyroglobulin
B) Thyroxine
C) Triiodothyronine
D) Pa ra fo llicu lar ce lls
E) C alc iton in

Question 11

Yo u w ou ld m os t like ly se e a go iter in

A) Iodine deficiency
B) H as him oto 's th yro iditis
C) Central hypothyroidism
D) Euthyroidism
E) M yxedema

Question 12

Most of the circulating T4 and T3 in the blood is

A) Free
B) Bo un d to alb um in
C) Bound to TBG (thyroxine binding globulin)
D) Bo un d to thyr ox ine bin din g p re alb um in
E) Bo un d to the su rfa ce of r ed blo od ce lls

Question 13

Receptors for T3 are found

A) O n th e s ur fa ce of m os t ce lls
B) In th e c ytop las m of m os t ce lls
C) In th e nu cleu s of m os t cells
D) Linked to G-protein coupled receptors in the liver and kidney
E) In the cytoplasm of brown fat

Question 14

The m ain se cr etio n o f th e th yro id g lan d is

A) T3
B) T4
C) Reverse T3
D) DIT
E) MIT

Question 15

TSH consists of an a and þ chain. The a ch ain in T SH is id en tica l to th at in

A) LH
B) FSH
C) HCG
D) All of the above
E) None of the above

Question 16

Which of the following is NOT a characteristic of cretinism?

A) Severe mental retardation
B) Shortness of stature
C) Deafness
D) Kid ney fa ilure
E) Poor motor coordination

Question 17

Which of the following is an example of central hypothyroidism?

A) Lack of iodine in the diet
B) De fec t in NIS
C) D ef ec t in p en dr in
D) Malfunctioning thyroid peroxidase
E) Defects in the TRH receptor

Question 18

TSH is secreted

A) From the anterior pituitary in response to TRH
B) From the hypothalamus in response to nervous excitation
C) Fr om the po ste rio r pit uita ry alo ng with ne ur op hys in
D) From the anterior pituitary in response to T3
E) From the thyroid gland in response to T3

Question 19

Deficiency of thyroid hormone during development causes

A) Ac ro m eg aly
B) Cretinism
C) Cushing's syndrome
D) Exopthalamos
E) Grave's disease

Question 20

Stimulation of the thyroid gland with TSH

A) Causes the thyroid cells to become flattened
B) Causes the thyroid cells to become m ore columnar
C) Decreas es the size of t he follic les be ca us e th ey c on su m e th e c ollo id
D) Uses a G q mechanism to stimulate thyroxine secretion
E) Inv olv es dire ct m an ipu latio n o f T SH -re sp on se ele m en ts in the follic ula r c ells

Question 21

The term "goiter " refe rs to

A) Hypothyroidism
B) An enlarged thyroid gland
C) Ac cu m ula tion of h yalu ro nic ac id in the de rm is
D) Inflamm ation of the thyroid gland
E) Iodine deficiency

Question 22

Graves disease is caused by

A) Excess production of TSH
B) Iodine poisoning
C) Goitrogens in the diet
D) LATS - long acting thyroid stimulator
E) Exopthalamos