Deck 67: The Calcitropic Hormones

Question 1

Calcitonin is secreted by

A) Four small glands embedded in the thyroid gland
B) Parafollicular cells in between the thyroid follicles
C) Gla nds locate d at the top o f the c hes t cavity
D) Os teob lasts
E) Patches of endocrine tissue located in the gut

Answer 1

B

Question 2

Calcium and Phosphorus homeostasis are linked because

A) Both Ca and Phosphate are released when bone is resorbed
B) Both Ca and Phosphate are in the urine
C) Ca com plexes with phosphate in the blood
D) Both Ca and Phosphate are absorbed in the intestine
E) Both A and C are true

Answer 2

E

Question 3

Which of the following is NOT an action of PTH?

A) It Increases activation of vitamin D by stimulating the 1a hydroxylase reaction
B) It Increases os teo cytic os teo lysis
C) It Increases os teo cla stic os teo lysis
D) It increa ses urina ry exc retion of ph osp hate
E) It Increases intestinal absorption of calcium

Answer 3

E

Question 4

Positive calcium balance means

A) Your bones are healthy
B) Yo u ar e inc reas ing Ca sto res d aily
C) Urinary Ca excretion is low
D) You do not have kidney stones
E) You have enough vitamin D

Question 5

Normal plasma total calcium concentration is regulated at a value around

A) 1.2 mM
B) 10 mg%
C) 5 mg%
D) 0.8 mg%
E) 4 g%

Question 6

The largest pool of calcium in the body is found in the

A) Plasma
B) Bone
B) Inte rs titial f luid
C) Intr ac ellu lar fluid
D) Ex tra ce llula r flu id

Question 7

PTH is a

A) Single chain peptide hormone 84 amino acids long
B) Glycopeptide
C) Com plex of two peptides, an A and a B chain, linked by disulfide bonds
D) M od ified am ino ac id
E) Steroid hormone

Question 8

For a person in net calcium balance

A) The am ount of Ca ingested in the diet is 800 mg /day
B) The am ount of Ca ingested in the diet is 1500 mg/day
C) The am ount of Ca lost from the body is 800 mg/day
D) The daily loss of Ca equals the daily gain of Ca
E) Total plasma Ca is maintained at 1.2 mM

Question 9

The bo ne m ine ra l ha s th e e m pir ica l for m ula

A) Ca₁₀ (PO₄)6 (OH )₂
B) Ca4₃(PO₄ )₂
C) Ca4₄ (HPO₄ )₂
D) Ca(HCO₃)₂
E) CaCO3

Question 10

The fraction of plasma calcium that is bound to protein is about

A) 10%
B) 90%
C) 40%
D) Almost none
E) Alm os t all

Question 11

PTH

A) Directly Increases Ca absorption from the intestine
B) Raises blood Ca and Increases urinary P excretion
C) Stimulates kidney 24 hydroxylation of vitamin D
D) Secretion Increases with Increases in plasma [Ca]
E) Is secreted by C cells of the thyroid gland

Question 12

PTH originates from

A) Four small glands embedded in the thyroid gland
B) Cells surrounding the thyroid follicles
C) Pa rathyro id glan ds loc ated at the to p of th e ch est c avity
D) Cells located in the parathalamus of the hypothalamus
E) Patches of endocrine tissue located in the gut

Question 13

The m ajor store of phosphorus in the body is in the

A) Plasma
B) Bone
B) Inte rs titial f luid
C) Intr ac ellu lar fluid
D) Ex tra ce llula r flu id

Question 14

The stimuli for calcitonin secretion include

A) H ype rc alc em ia
B) H ypo ca lce m ia
C) G I ho rm on es ga str in a nd ch ole cys tok inin
D) H ype rp ho sp ha tem ia
E) Both A and C are correct

Question 15

Negative calcium balance means

A) Your bones are not healthy
B) You do not have enough vitamin D
C) Urinary Ca excretion is high
D) You have kidney stones
E) Yo u ar e de crea sing Ca sto res d aily

Question 16

Calcitonin is secreted as a

A) Single chain peptide hormone 32 amino acids long
B) Glycopeptide
C) Com plex of two peptides, an A and a B chain, linked by disulfide bonds
D) M od ified am ino ac id
E) Steroid hormone

Question 17

The sig na l for Increased PT H se cr etio n is

A) H ype rp ho sp ha tem ia
B) H ype rp ho sp ha tur ia
C) Increased vitamin D
D) Hyp oc alce m ia
E) H ype rc alc em ia

Question 18

The larg es t sin k f or ph os ph or us lea vin g th e b od y is

A) Skin exfoliation
B) Feces
C) Sweat
D) Urine
E) Accretion onto bone

Question 19

Calcium in plasma is bound to plasma proteins by

A) Com plexing with hydroxyl groups on the proteins
B) Com plexing with amino groups on the proteins
C) Electrostatic attraction to amino groups on the proteins
D) Complexing with carboxyl groups on the proteins
E) Com plexing with the peptide bond backbone of the proteins

Question 20

Hypocalcemia can cause

A) Sluggish central nervous system responses
B) Pa in
C) Hypocalcemic tetany
D) Ectopic calcification
E) Heart arrhythmias

Question 21

Vitamin D is secreted by

A) The skin in response to UV radiation
B) The liver in response to PTH
C) The kidney in response to PTH
D) T he kid ne y in re sp on se to h ypo ca lce m ia
E) T he kid ne y in re sp on se to h ypo ph os ph ate m ia

Question 22

Control of vitamin D activation is accomplished by

A) PTH control of the liver 25 hydroxylase
B) PTH control of the liver 1 hydroxylase
C) PTH control of the kidney 25 hydroxylase
D) PTH con trol of the kidney 1 hydroxylase
E) Feedback inhibition of the liver 1 hydroxylase by vitamin D

Question 23

Vitamin D is activated by

A) Hydroxylation at the 25 position in the liver
B) Hydroxylation at the 1 position in the liver
C) Hydroxylation at the 1 position in the kidney
D) Hydroxylation at the 25 position in the kidney
E) Both A and C are true

Question 24

The m ajo r c irc ula ting for m of v itam in D is

A) Cholecalciferol
B) Ergocalciferol
C) 25 hydroxy cholecalciferol
D) 1, 25 dihydoxy cholecalciferol
E) 1 hydroxy cholecalciferol

Question 25

The m ajor action of calcitonin is

A) Increase Ca and Phosphate reabsorption from the kidney lumen
B) Incre ase oste obla st rec ruitm ent o f oste ocla sts
C) Decrea se bo ne reso rption by o steoclasts
D) Increases os teo cytic os teo lysis
E) D o n oth in; th er e a re no de fic ien cy o r ex ce ss dis ea se s f or ca lcito nin

Question 26

The pre cu rs or for vita m in D in th e s kin is

A) Tachysterol
B) 7-dehydro cholesterol
C) Pregnenolone
D) Lanosterol
E) Cholecalciferol