MSK 04 - Calcium, Phosphate, & Vitamin D in Bone Health Flashcards Preview

BPM1 Exam 3 - Musculoskeletal > MSK 04 - Calcium, Phosphate, & Vitamin D in Bone Health > Flashcards

Flashcards in MSK 04 - Calcium, Phosphate, & Vitamin D in Bone Health Deck (31)
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1
Q

Bone functions you didn’t already know about

A

Marrow produces RBCs, WBCs, growth factors and stores fatty acids

Storage of calcium, phosphorus, zinc, copper, and sodium

Temporarily absorb and store toxic heave metals to reduce their effects on the body

2
Q
A
3
Q

What is the primary inorganic mineral found in bone? What is this mineral primarily composed of?

A

Hydroxyapatite (aka - calcium apatite)

It is a cyrstalline structure of mostly calcium, phosphate, and -OH

4
Q

What is bone mass?

A

The amount of osseous tissue in any unit volume of bone

5
Q

What are the major determinants of bone mass?

A
6
Q

What are the three primary forms in which plasma calcium is found?

A
7
Q

What is the typical concentration of ionized calcium in ECF (plasma)?

A

1.2mmol/L

8
Q

What are the best dietary sources of calcium and what is its recommended daily allowance?

A
9
Q

What are the primary forms in which phosphorus is found in the body?

A
10
Q

What can enhance the absorptive efficiency of phosphate?

A

1,25(OH)2D (aka - Vitamin D)

11
Q

How is phosphate excreted and how is this excretion regulated?

A
12
Q

What are the major effects of PTH on the body?

A
13
Q

What are the major types of Vitamin D and where are they most commonly found?

A

Ergocalciferol - Vitamin D2 - found in plants

Cholecalciferol - Vitamin D3 - found in animals (made using sunlight)

These two forms are also in OTC supplements

14
Q

What is Vitamin D3 derived from?

A

7-dehydrocholesterol in the skin. It is converted to cholecalciferol after coming into contact with UV light

15
Q

Describe how Cholecalciferol (Vit D3) becomes hormonally active and what this hormone does.

A
  1. Cholecalciferol gets converted into 25-hydroxycholecalciferol (calcidiol) by 25-hydroxylase in the liver
  2. Calcidiol gets converted to hormonally active 1,25-dihydroxycholecalciferol (calcitriol) by 1-hydroxylase in the kidneys
  3. Calcitriol binds to intracellular receptor proteins that will translocate to the nucleus to stimulate or repress gene expression
16
Q
A
17
Q

What are the effects Vitamin D has on the intestine, bone, and kidneys?

A
18
Q
A
19
Q

What is calcitonin? Where does it come from and what does it do?

A

Calcitonin is a hormone released by the thyroid in response to raised plasma [Ca++]. Calcitonin inhibits the activity of osteoclasts leading to less bone resorption and a lower plasma [Ca++].

20
Q

Summarize the effects of Vitamin D and PTH on Ca++ and Phosphate levels. Which has the greater effect?

A
21
Q
A
22
Q

What are the four primary causes of a Vitamin D deficiency?

A
23
Q

What are the two disorders that most often result from a Vitamin D deficiency? What are their symptoms?

A
24
Q

Aside from low Vitamin D levels, what are some other lab findings that occur when there is a Vitamin D deficiency?

A

Hypocalcemia

Hypophosphatemia

Increased serum alkaline phosphate (ALP) from bone

25
Q

What are the causes, symptoms, and treatments for Vitamin D resistant rickets?

A
26
Q

What is hypervitaminosis D? What causes it? What are its symptoms?

A
27
Q

What are the common causes of Hypocalcemia? What lab findings can be used to diagnose hypocalcemia?

A

Hypocalcemia can be caused by low PTH levels (hypoparathyroidism)

It can also be caused by Vit D deficiency or impaired calcitriol production/action from renal failure. In these cases there will actually be high PTH levels (secondary hyperparathyroidism).

25 hydroxyvitamin D (calcidiol) levels will be low if hypocalcemia is being caused by Vitmain D deficiency. 1,25 dihydroxyvitamin D levels (calcitriol) will be low if hypocalcemia is being caused by renal insufficiency.

28
Q

Why are some common symptoms of hypocalcemia? What are the treatments?

A

Tetany (excitability of peripheral nerves) such as carpopedal spasms (spasmodic contraction of the muscles of the hands, feet, and especially the wrists and ankles), stridor (spasm of the glottis), and other convulsions (which can lead to difficulty breathing).

Severe Hypocalcemia can lead to cardiac arrhythmias

Treatments include calcium and Vit D supplements and, in emergencies, a calcium gluconate IV

29
Q

What are the common causes and lab findings of hypercalcemia?

A
30
Q

What are some common symptoms and causes of hypophosphatemia?

A
31
Q

What are some common causes, symptoms, and lab findings of hyperphosphatemia?

A