Calcitonin/Parathyroid

Question 1

Where is calcitonin synthesized?

Answer 1

Parafollicular cells AKA C-cells of the thyroid gland ***

Question 2

What is the chemical class of calcitonin?

Answer 2

PPP

Question 3

What are the primary functions of calcitonin?

Answer 3

Decrease plasma calcium **
Decrease osteoclast cell synthesis **
Decrease 1 hydroxylase enzyme activity

Question 4

What are the secondary functions of calcitonin?

Answer 4

Decrease digestion, PAIN ***, plasma phosphorus, and plasma sodium

Question 5

If calcitonin’s ability to decrease pain is a secondary function, what possesses the primary function of decreasing pain?

Answer 5

Endorphins

Question 6

Calcitonin controls the secretion and concentration of what substance?

Answer 6

Plasma calcium concentration

Question 7

Where can some calcitonin be secreted besides the C cells of the thyroid?

Answer 7

Thymus and parathyroid

Question 8

What is the effect of calcitonin on bone reabsorption? ***

Answer 8

Inhibition

Question 9

What does calcitonin do in the body?

Answer 9

Lowers calcium and phosphate in plasma ***

Question 10

Calcitonin can be used as treatment for what conditions?

Answer 10

Osteoporosis and Paget’s disease ***

Question 11

When is calcitonin used as treatment for osteoporosis?

Answer 11

If patient has adverse reactions to bisphosphonates

Question 12

How does calcitonin work as treatment for osteoporosis?

Answer 12

Prevents fractures

Question 13

What happens to bone with osteoporosis?

Answer 13

Bone mass and bone strength decreases
Porous bone
Bone breaks easily

Question 14

What is Paget’s disease (osteitis)?

Answer 14

Disorder of the normal bone remodeling ***

Bone formed is abnormal, enlarged, and weak

Question 15

Does the bone remodeling process occur faster or slower in patients with Paget’s disease?

Answer 15

Faster (therefore weak bone is formed)

Question 16

Paget’s disease is more common among what age group?

Answer 16

Over 50

Question 17

What are the symptoms of Paget’s disease?

Answer 17

Pain in bone/spine, fractures, bowed legs, cauda equina syndrome, enlarged skull (possible hearing problems)

Question 18

What are treatment options for Paget’s disease?

Answer 18

Bisphosphonates or calcitonin (if side effects seen with bisphosphonates)

Question 19

Parathormone (parathyroid hormone) essentially is the opposite of what other hormone?

Answer 19

Calcitonin

Question 20

Where is parathyroid hormone synthesized? *

Answer 20

Dark chief cells of the parathyroid gland *

Question 21

What chemical class is PTH?

Answer 21

PPP

Question 22

What does parathyroid hormone do?

Answer 22

Maintains calcium and phosphorus in plasma ***

Question 23

What condition arises from a deficiency in PTH?

Answer 23

Hypocalcaemia (decreased calcium in blood)

Question 24

What are the primary functions of parathyroid hormone? *

Answer 24

Stimulate growth *
Increase 100% vitamin D synthesis **
Increase plasma calcium *
Decrease plasma phosphorus

Question 25

What is the means by which parathyroid hormone stimulates growth and increases vitamin D synthesis?

Answer 25

Stimulation of 1-hydroxlase enzyme synthesis

Question 26

What is the means by which PTH increases plasma calcium? *

Answer 26

Increases renal reabsorption of calcium

Question 27

What is the most powerful hormone to increase plasma calcium? *

Answer 27

Parathyroid hormone (PTH) ***

Question 28

Does PTH stimulate osteoblast or osteoclast activity?

Answer 28

Osteoclast

Question 29

How does PTH decrease plasma phosphorus?

Answer 29

Decreases renal reabsorption of phosphorus

Question 30

What is the most powerful hormone to decrease phosphorus in plasma?

Answer 30

PTH

Question 31

PTH controls the secretion of what substance?

Answer 31

Plasma calcium

Question 32

What are the secondary functions of PTH? *

Answer 32

Big 4: increase metabolism, plasma glucose, BP, and immune response **** Also decreases plasma bicarbonate

Question 33

What can cause hypercalcemia?

Answer 33

Increase in hormones that increase plasma calcium Decrease in hormones that decrease plasma calcium Excessive sunlight, malignancies, hypervitaminosis Liver/kidney disorders

Question 34

Where is vitamin D synthesized?

Answer 34

Liver * (25-(OH) D3) and kidney (all active forms) *

Question 35

What is the chemical class of vitamin D?

Answer 35

Seco-steroid

Question 36

What is the precursor molecule of vitamin D that we obtain from our diet and sunlight?

Answer 36

7-dehydrocholesterol aka vitamin D3 aka cholecalciferol

Question 37

What kind of vitamin D do we obtain from supplements?

Answer 37

Vitamin D2

Question 38

What does the vitamin D become that is obtained from sunlight and diet when it is hydroxylated in the liver?

Answer 38

25-hydroxycholecalciferol ***(aka calcifediol)

Question 39

What is the final form of vitamin D seen after it passes through the kidneys?

Answer 39

1,25-dihydroxycholecalciferol (aka calcitriol or 1,25(OH)2D3) ***

Question 40

The activity of what substance leads to tight regulation of vitamin D by the kidneys?

Answer 40

1-alpha-hydroxylase

Question 41

What is the major controller of 1-alpha-hydroxylase? **

Answer 41

Parathyroid hormone **

Question 42

What are the primary functions of vitamin D? **

Answer 42

Increase linear height ** | Increase plasma calcium **

Question 43

What are the means by which vitamin D increases linear height?

Answer 43

Stimulation of osteoblast cell activity | Increase intestinal absorption of calcium

Question 44

What are the means by which vitamin D increases plasma calcium?

Answer 44

Stimulation of osteoclast cell activity Increase intestinal absorption of calcium Increase renal reabsorption of calcium

Question 45

What is the secondary function of vitamin D? *

Answer 45

Stimulate integumentary system (skin and hair) ** Stimulates immune resonse Increases oxygen transport and plasma phosphorus

Question 46

What condition results from a deficiency in thyroxine and vitamin D?

Answer 46

Alopecia (hair loss)

Question 47

What controls the secretion of vitamin D?

Answer 47

Plasma calcium * Sunlight * Hormones like PTH, glucagon, cortisol

Question 48

What hormone is most powerful in decreasing the secretion of vitamin D?

Answer 48

Glucagon

Question 49

What situations can cause vitamin D deficiency?

Answer 49

Sun shunning * | Strict vegetarian diet *

Question 50

What are foods that are good sources of vitamin D?

Answer 50

Fish liver oils, egg yolks, some fortified dairy products, fortified grain

Question 51

What is a major symptom of vitamin D deficiency?

Answer 51

Cognitive impairment *

Question 52

What conditions can result from vitamin D deficiency?

Answer 52

Rickets, severe asthma in children *, some cancers *, increased risk of cardiovascular disease *

Question 53

What is the blood test used to determine vitamin D deficiency? *

Answer 53

25-hydroxyvitamin D blood test

Question 54

What is the normal vitamin D range on a blood test?

Answer 54

20-50 nanograms/milliliter

Question 55

What level is considered deficient in vitamin D on a blood test?

Answer 55

12 ng/ml **

Question 56

What is the treatment for vitamin D deficiency?

Answer 56

Short sunlight exposure Foods rich in vitamin D Vitamin D supplements if needed (up to 4000 IUs)