Chapter 6: Calcium and Phosphate Regulation

Question 1

Majority of Ca+2

Answer 1

is in bone tissue, Least in cells - intracellular free Ca+2 is in the nanomolar range (10-9)

Question 2

Calcitriol

Answer 2

1. )activated vitamin D
2. )Increases calcium and phosphate in blood plasma
3. )Corrects hypocalcemia

Question 3

Parathyroid hormone (PTH)

Answer 3

1. )stimulates bone resorption
2. )Secreted by parathyroid gland (posterior to thyroid)
3. )Increases [Ca+2] in blood plasma, decreases Phosphate
4. )ESSENTIAL to human body
5. )Stimulates Osteoblast activity
6. )Synergistic to Calcitiriol
7. ) Increases phosphate secretion to kidneys

Question 4

Calcitonin

Answer 4

1. )stimulates bone deposition,
2. )Secreted by ‘C’ cells in thyroid gland,
3. )Decreases [Ca+2] and Phosphate in blood plasma
4. )Inhibit Osteoclast activity
5. ) Corrects Hyercalcemia

Question 5

Estrogen

Answer 5

Bone deposition

Question 6

Osteoporosis

Answer 6

low bone density, due to excess bone resorption and decreased bone deposition

Question 7

Hypercalcemia

Answer 7

high Ca+2, > (greater than) 11 mg/dL.
1.) Causes kidney stones, depression of the nervous system, emotional disturbances, muscle weakness, slow reflexes and sometimes cardiac arrest.

Question 8

Hypocalcemia

Answer 8

Low Ca+2, < 9 mg/dL.

1.) Condition of low calcium in blood, results in excessive excitability of nervous system, tremors, spasms and tetanus.

Question 9

Hyperphospatemia

Answer 9

High phosphate > 9 mg/dL

Question 10

Hypophosphatemia

Answer 10

Low phosphate < 2 mg/dL

Question 11

Osteoblasts

Answer 11

Bone deposition, synthesize collagen

Question 12

Osteoclasts

Answer 12

Bone resorption, secrete HCl acid to dissolve the hard bone matrix, secrete acid phosphatase (enzyme) to dissolve collagen in bone.

Question 13

Ca+2 Range

Answer 13

9-11 mg/dL

Question 14

Phosphate Range

Answer 14

2-9 mg/dL

Question 15

Osteocytes

Answer 15

Mature Osteoblasts

Question 16

Bone matrix

Answer 16

Ca+2 and Phosphate crystals called hydroxyapatite. They form spontaneously, Solubility inhibitors prevent their formation in soft tissue

Question 17

Osteogenic cells

Answer 17

Beginning of osteocyte. Osteogenic cells –> Osteoblasts –> Osteocyte

Question 18

Mineral deposition

Answer 18

1. ) Hydroxyapatite crystals form
2. ) Solubility-inhibitors prevent salt formation in other parts of body (soft tissue)
3. ) Osteoblasts in bone neutralize the solubility inhibitors

Question 19

Mineral resorption

Answer 19

Reabsorption: bone is ‘dissolved’ to re-absorb minerals to enter blood plasma.
1.) Osteoclasts dissolve bone by pumping H+ ions to ECF, Cl moves outside, H+ inside, and Hal dissolves bone

Question 20

Calcium imbalance

Answer 20

Hypercalcemia and Hypocalcemia. What are they?

Question 21

Hypocalcemic Tetanus

Answer 21

sharp flexion of wrists and or ankles is a characteristic sign of low blood Ca+2

Question 22

Calcitriol Synthesis

Answer 22

1. 7-dehydrocholesterol – converted by UV light to cholecalciferol
2. ) Cholecalciferol – converted by liver to calcidiol
3. ) Calcidiol– converted by kidney to calcitriol

7-dehydrocholesterol –> Cholecalciferol –> Calcidiol