ES. Calcium

Question 1

what is calcium involved in the structure of?

Answer 1

bone and tooth

Question 2

what does calcium store?

Answer 2

minerals

Question 3

in terms of a second messenger, what is calcium involved in?

Answer 3

muscle: excitation-contraction coupling
gland secretion
non steroid hormone action

Question 4

how do we maintain the concentration of calcium?

Answer 4

diet then absorbed in the GIT

Question 5

what hormones are involved in calcium homeostasis?

Answer 5

parathyroid
calcitonin
vit d

Question 6

where are parathyroid hormones secreted from and in response to what?

Answer 6

from parathyroid glands in response to low plasma

Question 7

how does parathyroid hormone act to increase plasma calcium?

Answer 7

• increased resorption of bone (osteoclasts)
• increased calcium ion resorption in kidney (with reduction in phosphate resorption)
• increased uptake in calcium ions form the intestines (assisted by vitamin d)

Question 8

where is calcitonin secreted from and in response to what?

Answer 8

from thyroid glands in response to high plasma

Question 9

how does calcitonin lower plasma calcium?

Answer 9

• increased formation of bone (osteoblasts)
• decreased calcium resorption in kidney

Question 10

does calcitonin play a major role in calcium homeostasis?

Answer 10

no as it lacks pathological effects

Question 11

does calcitonin play a major role in calcium homeostasis?

Answer 11

no as it lacks pathological effects

Question 12

which hormones increase bone formation and bone mass?

Answer 12

calcitonin
growth hormone
IGF-1
insulin
oestrogen
testosterone

Question 13

which hormones increase bone resorption and decrease bone mass?

Answer 13

cortisol
parathyroid hormone
thyroid hormone

Question 14

what do osteoblasts do?

Answer 14

synthesise and secrete collagen fibres forming a matrix layer mineralised by calcium salts
PRODUCE BONE

Question 15

what are osteocytes?

Answer 15

osteoblasts that are trapped in the bone matrix

Question 16

where do osteocytes lie and how do they contact other cells?

Answer 16

in bony lacunae and contact other cells via long cytoplasmic processes

Question 17

what is the function of osteoclasts?

Answer 17

resorb bone

Question 18

what are osteoclasts? (structure)

Answer 18

large, multinucleate cells
derived from macrophages

Question 19

where do osteoclasts lie?

Answer 19

in depressions (howships lacunae)

Question 20

what is hypercalcaemia?

Answer 20

raised Ca2+

Question 21

what is hypocalcaemia?

Answer 21

reduced Ca2+

Question 22

what hypocalcaemia due to?

Answer 22

• decreased Ca2+ intake
• excessive Ca2+ loss
• alkalosis (low Ca2+)

Question 23

what effect does low Ca2+ have on nerve excitability?
what does this feel like?

Answer 23

increases it which feels like pins and needles/ muscle spasms

Question 23

what effect does low Ca2+ have on nerve excitability?
what does this feel like?

Answer 23

increases it which feels like pins and needles/ muscle spasms

Question 24

what can lead to hypocalcaemia?

Answer 24

hyperventilation (panic attack) which can cause alkalosis so decreased co2

Question 25

what is the remedy for alkalosis ?

Answer 25

trap co2 in patients lungs so rebreathe air from a bag

Question 26

what can hyperparathyroidism lead to?

Answer 26

osteitis fibrosa cystica = areas of demineralisation in skull and leg bones

Question 27

how would osteitis fibrosa cystica in the gingiva present in a radiograph?

Answer 27

radiolucent

Question 28

how can hypothyroidism effect the teeth?

Answer 28

defective mineralisation of teeth due to low blood calcium levels due to under secretion of PTH

Question 29

what can a vit d deficiency lead to in adults and children?

Answer 29

rickets - children osteomalacia - adults

Question 30

what effect does vit d deficiency have on the uptake of calcium by the GIT?

Answer 30

decreases the uptake

Question 31

what effect does a vitamin d deficiency have on bone?

Answer 31

unmineralised so lacks rigidity

Question 32

what clinical consequences does a change in calcitonin levels have?

Answer 32

none therefor not essential for regulation of plasma

Question 33

what is osteoporosis?

Answer 33

decreased bone mass and density

Question 34

what is ostepetrosis?

Answer 34

increased bone mass and density

Question 35

what part of the bone does osteoporosis effect?

Answer 35

reached thickness of cortical bone in the femur

Question 36

what causes osteoporosis?

Answer 36

common in elderly women earlier due to menopause corticosteroids nutritional deficiency

Question 37

how does osteoporosis show on a radiograph?

Answer 37

tooth roots are indistinct

Question 38

what can people with osteoporosis be prone to?

Answer 38

fracture and chronic infection

Question 39

how does osteopetrosis effect blood supply?

Answer 39

reduces it

Question 40

is osteopetrosis present in the mandible or the maxilla?

Answer 40

mandible