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Flashcards in calcium physiology Deck (22)
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1

give some examples of the role calcium plays in the body

- bone and tooth structure
- mineral store
- action potentials in cardiac muscle
- membrane potentials
- 2nd messengers
- blood clotting

2

which 3 substances maintain calcium homeostasis?

- parathyroid hormone
- calcitonin
- Vit d

3

when is parathyroid hormone secreted?

when plasma calcium levels are low

4

how does parathyroid hormone work to increase plasma calcium levels?

- increase bone resorption
-increase calcium uptake by kidneys (decreased PO4 resorption)
- increase calcium uptake from intestine (assisted by vii d)

5

when is calcitonin secreted?

in response to high plasma calcium levels

6

how does calcitonin act to lower blood plasma?

- increase bone formation
- decrees calcium resorption in kidneys

7

does calcitonin play a major role in calcium homeostasis?

no

8

what role does vit d play in calcium uptake?

vit d is needed to absorb calcium

9

which hormones increase bone formation and bone mass?

- calcitonin
- growth hormone
- IGF-1
- insulin
- oestrogen
- testosterone

10

which hormones increase bone resorption and decrease bone mass?

- cortisol
- parathyroid hormone
- thyroid hormone

11

what role do osteoblasts play in the mineralisation of bone by calcium salts?

synthesise and secrete collagen fibres forming matrix later mineralised by calcium salts

12

raised calcium levels is known as?

hypercalceamia

13

decreased calcium levels is known as?

hypocalcaemia

14

what is tetany?

A condition that is due usually to low blood calcium

15

what may cause hypocalceamic tetany?

- decreased calcium intake
- excessive calcium loss
- alkalosis (low calcium)

16

what effect does low calcium have on nerves?

increased nerve excitability - spasms, pins and needles

17

decreased secretion of parathyroid hormone cause what condition?

hypoparathyroidism

18

what effect does hypoparathyroidism have on the teeth?

defective tooth mineralisation

19

vitamin D defence may cause what ?

- decreased calcium uptake from GI
- under mineralisation of bone
- bones lack rigidity
- rickets in children
- osteomalacia in adults

20

decreased bone mass and density is known as?

osteoporosis

21

increased bone mass and density is known as?

osteoporosis

22

does parathyroid hormone work on teeth?

no