Pth/calcitonin

Front 1

How much of our Ca2+ is found in bone?

Back 1

98.9%

Front 2

How much of our Ca2+ is found in intercellular spaces (in the cells)?

Back 2

1%

Front 3

How much Ca2+ is found in extracellular fluid?

Back 3

0.1%

Front 4

How much of our PHOSPHATE is found in bone?

Back 4

85%

Front 5

Hw much PHOSPHATE is found in intercellular spaces (in the cells)?

Back 5

15%

Front 6

How much PHOSPHATE is found in extracellular fluid? What conc (mg/dL) is this?

Back 6

<1% [=4 mg/dL]

Front 7

What % of the calcium in plasma is combined with plasma proteins? Is this diffusaible through the capillaries?

Back 7

41%; not diffusible

Front 8

What % of the calcium in plasma is combined with plasma anions (citrate, phosphate)? Is this diffusible thorugh the capillaries?

Back 8

9%; yes diffusible, just not ionized

Front 9

What % of the calcium in plasma is ionized? Is this diffusible thorugh the capillaries?

Back 9

50%; diffusible and ionized

Front 10

Concentration of ionized Ca2+ in blood/intersitium (in mM)?

Back 10

1.2 mM

Front 11

TF there is strict regulation of Pi because even small changes can cause immediate effects on body.

Back 11

False - body can handle 2-3x changes in plasma Pi with no immediate effects

Front 12

There is strict regulation of extracellular Ca2+. What is the normal conc of Ca2+[e]?

Back 12

2.4 mM (9.4mg/dl)

Front 13

At what extracellular Ca2+ conc do we see tetany? is this hypocal or hypercal

Back 13

7 mg/dl; hypocalcemia (rickets)

Front 14

At what extracellular Ca2+ conc. do we see depressive CNS effects? hypo or hypercal?

Back 14

12 mg/dL; hypercalcemia

Front 15

At what extracellular Ca2+ conc. do we find CaPO4 crystals throughout body, which can cause death?

Back 15

17 mg/dL; hypercalcemia

Front 16

Where is sodium mostly absorbed in the nephron?

Back 16

PCT

Front 17

Hypercalcemia causes excitation or depression of CNS function?

Back 17

depression - lots of Ca2+ means blocking more and more Na+-channels

Front 18

Hypocalcemia causes excitation or depression of CNS function?

Back 18

excitation - Ca2+ acts as a Na+ channel blocker, so with less Ca2+ you get more depol

Front 19

Muscle tetany is a symptom of hyper- or hypocalcemia?

Back 19

hypocalcemia

Front 20

Carpopedal spasm is a symptom of hyper- or hypocalcemia?

Back 20

hypocalcemia

Front 21

What % reduction in Ca2+[e] is fatal?

Back 21

60%

Front 22

At what % reduction in Ca2+[e] do we see excitiation of PNS and spontatnoues discharges to skeletal muscles during contraction?

Back 22

50%

Front 23

At what % reduction in Ca2+[e] do we see tetany?

Back 23

35%

Front 24

Hyper- or hypocalcemia? sluggish reflexes

Back 24

hypercalcemia

Front 25

Hyper- or hypocalcemia? loss of appetite/constipation

Back 25

hypercalcemia

Front 26

Hyper- or hypocalcemia? decreased QT interval

Back 26

hypercalcemia

Front 27

Hyper- or hypocalcemia? decreased GI contractility

Back 27

hypercalcemia

Front 28

2 forms of inorganic phosphate (Pi) in da plasma and %s

Back 28

H2PO4- (.26 mM); HPO42- (1.05 mM)

Front 29

TF Acidic pH increases [HPO42-]

Back 29

False, acid increases H2PO4- [more h+]

Front 30

TF alkaline pH increases [HPO42-]

Back 30

TRUE

Front 31

TF it is easy to absorb Pi from diet via GI tract.

Back 31

TRUE

Front 32

What assists more Pi absorption in GI tract

Back 32

Vit D

Front 33

What hormone regulates Pi excretion?

Back 33

PTH

Front 34

plasma Pi level is usually (in mM)

Back 34

1 mM

Front 35

Calcium salts represent what % of bone?

Back 35

70%

Front 36

Organic matrix represent what % of bone?

Back 36

30%

Front 37

What percent of the organic matrix of bone is collagen fibers? What's the rest?

Back 37

95%; ground substance like chondroitin sulfate and hyaluronic acid

Front 38

In addition to Pi and Ca2+, what 4 other ions are present in bone, conjugated to hydroxyapatite crystals.

Back 38

Mg2+, Na+, K+, carbonate ions

Front 39

Why does hydroxyapatite not precipitate in tissues despite high Ca2+ and high Pi in extracellular fluid?

Back 39

Inhibitors like pyrophosphate

Front 40

Deposition of radioactive substances in bone may cause...

Back 40

osteogenic sarcoma

Front 41

term: abnormal Ca2+ deposition in nonosseous tissues

Back 41

arteriosclerosis

Front 42

TF collagen fibers provide compression strength

Back 42

false - tensile strength

Front 43

TF calcium salt provides compression strength

Back 43

TRUE

Front 44

What do the hydroxyapatite crystals bind tightly to in bone?

Back 44

collagen fibrils

Front 45

What % of your daily Ca2+ intake is pooed out?

Back 45

90%

Front 46

What % of your daily Ca2+ intake is peed out?

Back 46

10%

Front 47

What % of your daily Ca2+ intake is reabsorbed by kidney?

Back 47

99%

Front 48

What is the active form of Vitamin D? What is it formed by?

Back 48

1,25-dihydroxycholecalciferol; liver(25), then kidney (1,25)

Front 49

TF 24,25-dihydrocholecalciferol is the active form of vitamin D

Back 49

false - inactive

Front 50

AA# for PTH preprohormone, prohormone, and hormone

Back 50

110 --> 90 --> 84

Front 51

How are Vit D and Ca2+ related?

Back 51

Vitamin D increases Ca2+ absorption from intestinal tract

Front 52

At high Ca2+ levels, what happens to PTH and vit D?

Back 52

PTH is suppressed and 1,25-dhcc is converted to the less active 24,25-hcc so you get less Ca2+ absorption

Front 53

Almost all PTH is synthesized and secreted by what cells of the PT gland?

Back 53

chief cells

Front 54

Synth. and secretion of calcitonin occurs in which cels? Where are they found?

Back 54

parafollicular cells in fluid b/w thyroid gland follicles

Front 55

Does PTH increase or decrease Ca2+/phosphate absrptn from intestine?

Back 55

increases (by inc. 1,25-dhcc from kidneys)

Front 56

Does PTH increase or decrease Ca2+/phosphate absrptn from bone? how?

Back 56

increases; rapid activation of osteocytes (inc. Ca2+ absorption), slow prolif of osteoclasts (inc. bone resorption)

Front 57

TF PTH increases phosphate excretion from kidneys.

Back 57

true, even tho it increases absoprtion of it from bone - more is released

Front 58

Does PTH increase or decrease Ca2+/phosphate elimination from kidneys?

Back 58

decreases Ca elimination

Front 59

what mediates the effects of PTH

Back 59

cAMP

Front 60

What is rickets? What happens to PT glands in rickets?

Back 60

Rickets is only a small reduction Ca2+ in ECF, but the response is parathyroid gland hypertrophy so you make more PTH to release more Ca2+ into the blood by breaking down your bones

Front 61

TF Osteoblasts are nonfunctional in rickets.

Back 61

False - they lay down osteoid but calcification doesnt occur - kids dont have enough from lack of Vit D produciotn in the wintertime

Front 62

Lactation would increase or decrease size of PT glands?

Back 62

increase because youre using up a lot of your Ca2+, so you need more (PTH)

Front 63

Which has a greater quant. effect in Ca2+ regulation - pth or calcitonin?

Back 63

pth

Front 64

RANK is on osteoclast or osteoblast

Back 64

osteoclast holds the receptor RANK

Front 65

RANKL is on osteoclast or osteoblast; another name for rankl?

Back 65

osteoblast holds the ligand RANKL; OPGL

Front 66

How does OPG protect bone?

Back 66

binds OPGL and prevents differentiaiton of bone resorbing osteoclasts

Front 67

Effect of PTH on RANKL formation

Back 67

increases RANKL [mech to break down bone]

Front 68

Effect of PTH on OPG formation

Back 68

decreases OPG [wanna break down bone]

Front 69

term: formation between 2 broken ends of bone

Back 69

callus

Front 70

How do ortho forces effect bone?

Back 70

change OPG, RANKL levels in gingival crevicular fluid

Front 71

Compressed PDL cells make a lot of RANKL or OPGL?

Back 71

RANKL - upregulate bone remodeling and root resportion during ortho tooth movement

Front 72

Tetany in hypo or hyperparathyroidism?

Back 72

hypoparathyroidism

Front 73

TF PTH replacement is an effective tx for hypoparathyroidism

Back 73

false - rapid elimination, expensive, antibody production all

Front 74

How do you treat hypoparathyroidism?

Back 74

Vit D + Calcium supplements [tryna increase ca2+ in blood since lacking PTH bone breakdown]

Front 75

PRIMARY cause of hyperparathyroidism

Back 75

tumor (more in women)

Front 76

TF We see elevated calcium and phosphate levels in hyperparathyroidism.

Back 76

False - increased calcium but DECREASED PHOSPHATE b/c of renal excreiton

Front 77

What is the diagnostic sign of hyperparathyroidism?

Back 77

increased plasma ALKALINE PHOSPHATASE (inc. osteoblast activity)

Front 78

Kidney stones in hyper or hypoparathyroidism?

Back 78

hyperparathyroidism (too much calcium)

Front 79

What is secondary hyperpt?

Back 79

high PTH to compensate for hypocalcemia (can be caused by Vit D deficiency, chronic renal disease, ostoemalacia)

Front 80

What is steatorrhea?

Back 80

failure of fat absorption; vit D is fat soluble, so you dont get enough vit D

Front 81

Why is congenital hypophosphatemia (type of rickets) resistant to Vit D treatmement?

Back 81

loss of renal resorption; treat with phosphate compounds

Front 82

renal rickets cuase

Back 82

destroyed kidneys means no vit D, means no calcium absorption, so you get bone resorptin

Front 83

most common bone disease

Back 83

osteoporosis (can be caused by hyperpt, lack of physical stress, malnutrition, lack of vit C, loss of estrogen, cushing's because of inc. in protein catabolism)