5.6 Calcium Homeostasis Flashcards Preview

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Flashcards in 5.6 Calcium Homeostasis Deck (29):
1

Importance of calcium

Nerve and muscle excitability
Neurotransmitter release from axon terminals
2nd messenger in intracellular signaling
Major constituent of bone

2

Most of total body calcium is in ___

Bone

3

Importance of phosphorus

Enzyme activation/inactivation
Major constituent of DNA, RNA and other phosphoproteins
Major component of bone

4

Majority of phosphorus is in __

Bone

5

Contains the second most abundant storage of phosphorus

ICF

6

The most biologically important form of calcium

Free ionized form

7

Calcium RDA for adults

around 1000 mg

8

Major dietary source of calcium

Dairy products

9

Organ which is the major site of phosphorus homeostasis

Kidneys

10

The Bone forming cell responsible for secreting and depositing organic matrix that will form the new bone (osteoid)

Osteoblast

11

Cells that promote bone resorption

Osteoclast

12

Signals for activation and maturation of osteoclasts

RANK ligands
Various interleukins
Cytokines

13

A group of osteoclasts and osteoblasts that carries out the process of bone remodeling

BMU or Basic Multicellular Unit

14

Relative length of bone remodeling

3 months

15

Most important hormone in regulating ca

Parathyroid hormone

16

Primary regulator for secretion of PTH

Ionized calcium

17

Primary stimulus for secretion of PTH

Decreased plasma ionized calcium

18

in the presences of calcium, GPCR activates this effector which leads to the inhibitions of PTH secretion and synthesis

Protein Lipase C/phospholipase C

19

Hormone which inhibits gene expression of PTH

Calcitriol

20

___ terminal of PTH contains the biologically active sequence

Amino terminal

21

Net effect of PTH

Increase serum calcium
Decrease serum phosphorus

22

Effect of PTH on Bone

Stimulate both osteoblasts (directly) and osteoclasts (indirectly)

23

How PTH increases serum Ca via the kidneys

PTH increases Ca reabsorption at the thick ascending limb and early distal convoluted tubule

24

Effect of calcitriol on bone

Represses synthesis of type 1 collagen
induces synthesis of osteocalcin

25

Enzyme which acts upon 25 hydroxycholecalciferol to produce 1,25 dihydroxycholecalciferol (calcitriol; activated form of calcium)

1alpha-hydroxylase

26

Source of calcitonin

Thyroid gland, C cells or clear cells or parafollicular cells

27

Effect of calcitonin

Promote bone deposition and inhibits osteoclastic resorption

28

PTH and Ca levels in hypoparathyroidism

Low PTH, Low Ca

29

Signs and symptoms of hypocalcemia

Neuromuscular irritability: cramping, tetany, tingling, paresthesia, chvostek's sign