Calcium Phosphate Flashcards Preview

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Flashcards in Calcium Phosphate Deck (53)
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1
Q

Responses of physiologic system to levels of Ca and P are in regards to the levels here:

A

blood

2
Q

Net drive of Ca and P into bone:

A

growing

3
Q

What hormones help regulate the net loss and gain of bone?

A

Estrogens and testosterone

4
Q

These cells regulate Ca levels in blood:

A

C cells, production and release of calcitonin (thyroid tissues)

5
Q

True or False? Calcitonin is very important physiologically.

A

F

6
Q

Cells that make parathyroid hormone:

A

chief cells

7
Q

Procedure for hyperthyroidism:

A

thyroidectomy

8
Q

Issues with thyroid removal

A

reverse hyperthroidism state and create an iatrogenic issue in Ca and P balance because parathyroid tissue was accidentally cut out as well

9
Q

primary action of calcitonin:

A

Excrete Ca and P

10
Q

Calcitonin is more important for what animal?

A

fish

11
Q

Drug for postmenopausal women at risk for osteoporosis:

A

calcitonin, decreases osteoclasts, prevents osteoporosis

12
Q

3 important hormones for Ca and P homeostasis:

A

parathyroid hormone, vitamin D, calcitonin

13
Q

True or False? Bone is a fast responder to changes in Ca and P levels.

A

F. slow

14
Q

True or False? Direction of Ca and P movement is the same for the gut and bone.

A

T

15
Q

Differential regulation of Calcium levels vs. P levels occurs here:

A

kidney, some passive and some active channels

16
Q

What affects Ca and P regulation at the level of the kidney

A

parathyroid hormone

17
Q

Low blood calcium:

A

take up in the gastrointestinal or excrete less, reabsorb more from filtrate.

18
Q

Functions of parathyroid hormones

A

to increase plasma calcium levels

19
Q

High calcium levels affect parathyroid hormone levels in this way:

A

inhibit parathyroid hormone secretion

20
Q

Low calcium levels:

A

parathyroid hormone release and calcium reabsorption in kidney

21
Q

___% of calcium that enters kidney is reabsorbed

A

98

22
Q

how much Ca and P is taken in via the diet daily?

A

1gm

23
Q

What % of filtered load …

A

90% of filtered load

24
Q

Reabsorption via calcium transporter in the distal tubule

A

active transport stimulated via parathyroid hormone (increases calcium reabsorption)

25
Q

Proximal tubule, hydroxylases

A

hormone stimulate proximal tubule to activate vit D (steroid) goes to gut to increase absorption of both Ca and P, stimulates production of calbindin (calcium binding in the duodenum, transport into the blood)

26
Q

Target of Vit D:

A

gut to increases Ca and P(more passive for P)

27
Q

2 ways parathyroid hormone increase Ca and P levels:

A

directly increases reabsorption of calcium in distal tubule AND VIT D3 activated to get more Ca and P absorption at the gut (also increased P transport)

28
Q

Issue with increased P uptake:

A

fixing hypocalcemia, you are now hyperphosphatemic

29
Q

Why does the increase in P occur?

A

Vitamin D levels

30
Q

What inhibits the Na/P transporter in the proximal tubule:

A

parathyroid hormone, increasing its excretion (loss of na and Water, now that must be corrected)

31
Q

Calcitonin functions:

A

inhibition of reuptake of Ca and P to lower blood Ca and P levels

32
Q

Bone is stimulated by:

A

parathyroid hormone, vitamin d and calcitonin

33
Q

When you want to leach Ca and P out of the bone:

A

stimulate osteocytes that release Ca and P in the canaliculi out of the bone, mobilize into blood pool, causing osteocytic osteo breakdown of bone without degrading the structure itself (parathyroid hormone and vitamin d are non-destructive), leave the matrix intact

34
Q

Function of ?

A

restore pool and mobilize Ca and P out of bone and into he blood

35
Q

Turns inactive to active Vitamin D form:

A

parathyroid hormone

36
Q

Where is the phosphate sensor?

A

proximal tubule of kidney

37
Q

low phosphate levels:

A

activate hydrolase to convert inactive vitamin d to active

38
Q

hypophosphatemia is caused by:

A

malnutrition, alcoholism, respiratory alkylosis

39
Q

vitamin d effect on gut:

A

increases Ca and P in gut

40
Q

First line of defense is here to normalize Ca and P levels

A

gut, then bone

41
Q

intracellularly transport across gut or take p from bone:

A

p levels are restored, now we are hypercalcemic, sensed by chief cells,

42
Q

inhibt parathyroid hormone:

A

block resorption (decreases activity of Calcium pump in distal tubule and a little effect on the resporption of P in the poximal tubule)

43
Q

glucocorticoids effect on bone:

A

long term bone growth retardation

44
Q

cortisol or increases stress, effect on Ca and P levels:

A

block the transport of Ca and P across gut because the actions of —

45
Q

another function of glucocorticoids:

A

effect differentiation of osteoblasts (decrease activity, can’t lie down fresh osteoid matrix)

46
Q

Which bones will be targeted first for bone breakdown?

A

compact bone and those with a larger tissues content

47
Q

High calcium levels:

A

inhibition of parathyroid hormone levels

48
Q

dehydrocholesterol + light:

A

cholecalciferol (non-active vitamin d3, broken steroid nucleus, lipophilic, enters epithelial cells)

49
Q

free calcium is the killer, active vitamin d damage is prevented by;

A

calbindin

50
Q

Where is cholecalciferol activated?

A

liver 25 hypoxie vitamin d (low biological activity)

51
Q

Which form of Vitamin D is floating around in blood?

A

25 hydroxycholecalciferol vitamin d

52
Q

hormonal regulation point for active vitamin d:

A

1-hyroxylase that is sensitive to parathyroid hormone or low phosphate levels, activates inactive to active vitamin d3

53
Q

Low calcium is sensed here:

A

parathyroid gland