Calcium Metabolism

Question 1

Serum conc of calcium

Answer 1

2.2-2.6

Question 2

Serum conc of phosphate

Answer 2

0.7-1.4

Question 3

Magnesium serum conc

Answer 3

0.8-1.2

Question 4

Organ systems ca metabolism

Answer 4

Skeleton
Kidney
Gi tract

Question 5

Calcitrophic hormones

Answer 5

Parathyroid hormone
Calcitonin
Vitamin D
Parathyroid hormone related protein

Question 6

Forms of circulating calcium

Answer 6

Protein bound-inactive,not excreted
Ionized-active,excreted
Complexed with phosphate,bicarbonate and citrate

Question 7

Calcium is

Answer 7

Essential

Question 8

Calcium balance

Answer 8

Input=output

Question 9

Negative balance of calcium

Answer 9

Osteoporosis

Question 10

Calcium means of transport into cell

Answer 10

Translocation across cell membrane ,Er,mitochondria

Ca atpase

Question 11

Feedback inhibition of ca

Answer 11

Decreased ca->increased pth-> stimulate kidney->vit d->git->release ca.

Also pth-> bone resorption-> ca

Question 12

Parathyroid hormone structure

Answer 12

Prepropth(115aa)->propth->(90aa)->cleaved at position 6/7 ->84 residues(mature peptide)

Question 13

Factors that regulate pth synthesis

Answer 13

Calcium regulates secretion and transcription. Inversely proportional

Transcription Inhibited by high vt D

Question 14

Pth function

Answer 14

Increases calcium

Decreases inorganic phosphate by excretion

Question 15

Bone components

Answer 15

Organic -33%- collagen,structural proteins like proteoglycans,phosphoproteins,osteocalcin

Inorganic-67%-hydroxyapatite with some calcium phosphate

Question 16

Osteoblast function

Answer 16

Bone formation
Bone mineralization
Formation of matrix proteins
Activation of osteoclast by producing RANKL

Question 17

Function of osteoclast

Answer 17

Resorption of bone

RANKL TO RANK which causes differentiation into osteoclasts

Question 18

Osteoblast encased in bone

Answer 18

Osteoclast

Question 19

Osteoblasts have receptors for

Answer 19

Pth
Vit d
Growth factors
Cytokines

Question 20

Pth

Answer 20

Is trying to cause bone resorption

Prevents osteoblast to osteocyte
Promotes osteoblast to osteoclast
Promotes osteoblast activation of osteoclast

Question 21

Pth site of action on kidney

Answer 21

Acts on pct (80%)and dct (20%)but primarily on dct bc pct reabsorption is vis osmosis

Question 22

Calcitonin produced by

Answer 22

Parafollicar c cells

32aa

Question 23

Calcitonin fxn

Answer 23

Inhibits bone resorption

Aids calcium excretion

Question 24

Activationof vit d

Answer 24

Skin->liver->kidney

7dehydrocholesterol->cholecalciferol->25hydroxycholecalciferol when acted on by 25 hydroxylase->1,25dihydroxycholecalceferol when acted on by 1 alpha hudroxylase

Question 25

How does activated vit d work

Answer 25

Activated vit d->binding to receptor on intestines->transcription of genes ie calbindin->transporter of ca Nongenomic-allows ca through luminal brush border

Question 26

Vit d deficiency

Answer 26

Rickets in children | Osteomalacia-most prominent

Question 27

Deficiency in alpha 1 hydroxylsse

Answer 27

Vitamin d resistant rickets Hypoplastic teeth Retarded eruption

Question 28

Pthrp isoforms

Answer 28

3 | 138,141,173 due to alternative splicing

Question 29

Pthrp

Answer 29

Can activate pth receptor

Question 30

Functions of pthrp

Answer 30

Tranfer calcium to milk Fetal development Can cause hypercalcemia of malignancy

Question 31

Causes of hypocalcemia

Answer 31

``` Idiopathic After exposure to radiation Postoperative Vit d deficiency Malabsorption Liver dx Kidney dx Vit d resistance Psiedohyperparsthyroidsm-pth resistance ```

Question 32

Psuedoparathroidsm symptoms

Answer 32

``` Hypocalcemia Hyperphosphatemia Tetany Siezures Hypoplasia of enamel Absence of eruption ```

Question 33

Causes of hypercalcemia

Answer 33

Common Hyperparathyroidsm Malognancy Vit d intoxication Uncommon Renal failuire Sarcoidosis Multiple myeloma

Question 34

Symptoms of hypetcalcemia

Answer 34

``` Bone ache Muscle weakness Arrhythmia Lethargy Depression Confusion ```

Question 35

Common sumptom of hypercalcemia

Answer 35

Pain in bones Stones Abdominal pain

Question 36

Treat hypercalcemia of malignancy with

Answer 36

Bisphosphatones. Inhibits osteoclastic activity

Question 37

Treatment of serum ca>3

Answer 37

Nacl iv

Question 38

Osteoporosis

Answer 38

Reduction in bone mineral density for age,srx group

Question 39

Factors affecting peak bone mass

Answer 39

``` Gender-Males>females Race-blacks>white Genetic Gonadal steroids-increase pbm Groth hormone Calcium intake Excercise ```

Question 40

Sequale of osteoporosis

Answer 40

Dowagers hump | Loss of 6-9inches in height in upper thoracic vertebra

Question 41

Treatment of osteoporosis

Answer 41

Estrogen treatment-inhibit osteoclast activity ``` Intake of calcium Excercise daily Bisphosphatones Calcitonin Vit d Pth (forteo) ```