LMP301 Lecture 11: Calcium, Vit D, Parathyroid Flashcards Preview

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Flashcards in LMP301 Lecture 11: Calcium, Vit D, Parathyroid Deck (90)
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1

Where is calcium excreted?

- intestines (poop)
- kidneys

2

Which hormones regulate calcium homeostatsis?

- parathyroid hormone
- 1,25 (OH)2 vit D
- calcitonin

3

What stimulates PTH release?

low Ca++

4

effect of PTH on bone

reabsorption (break down)

5

effect of PTH on kidney

- Ca++ reabsorption
- P secretion
- incr. 1-OH'ase
- incr. 1,25 (OH)2 vit D

6

Where does PTH act on?

- bones
- kidneys

7

How do we get to the active form of 1,25 (OH)2 vit D?

1. pro-vitamin D --(UV)--> vit D
2. vit D --(25-OH'ase)--> 25-(OH)D3
3. 25-(OH)D3 --(1a-OH'ase)--> 1,25-(OH)2D3

8

Where can 25-OH'ase be found?

liver

9

where can 1a-OH'ase be found?

many tissues, including kidneys, pancreas, colon, prostate, breasts...

10

The active 1,25 (OH)2 vit D can be converted into the inactive...

1,24,25-(OH)3D3

11

25 OH vit D can be converted into ____ by ____ (not the reaction to make 1,25-(OH)2D3)

24,25-(OH)2D3
24-OH'ase

12

Sources of vit D3

- supplement
- sunlight on skin
- milk
- salmon

13

function of 1,25-(OH)2D3 at pancreas, colon, prostate, breasts...

regulate cell growth (prevent cancer)

Prevent autoimmune diseases

14

function of 1,25-(OH)2D3 at kidneys

prevent autoimmune diseases

maintain calcium homoeostasis (muscle & bone health)

15

Where does 1,25-(OH)2D3 act on?

- intestines
- bones
- parathyroid gland

16

effect of 1,25-(OH)2D3 on intestines

- increase Ca absorption
- incr P absorption

17

Overall effect of 1,25-(OH)2D3

raise blood Ca++ levels

18

effect of 1,25-(OH)2D3 on bone

increase reabsoprtion

19

effect of 1,25-(OH)2D3 on parathyroid gland

decrease PTH

20

Feedback of 1,25-(OH)2D3

- inhibit its own synthesis
- promotes its own breakdown

21

1,25-(OH)2D3 is bound to ___ when in circulation

vit D binding protein

22

receptor for 1,25-(OH)2D3

nuclear vit D receptor

23

calcitonin is secreted by...

parafollicular / C cells of thyroid gland

24

Secretion of calcitonin is stimulated by...

- high Ca
- GI hormones

25

Effect of calcitonin

- lower serum CA
- lower serum P
- stops bone reabsorption

26

Calcitonin is used as treatment for which bone diseases?

- post-menopausal osteoporosis
- Paget's disease

27

Calcitonin is a tumour marker for...

medullary thyroid carcinoma (tumor of the C cells in thyroid gland)

28

Tetany is a symptom of...

hypocalcemia

29

Tetany

flexed wrist & ankle joint, muscle twitching, cramps

30

Hypocalcemia is usually present with...

neuromuscular hyperexcitability (tetany, Trousseau's sign)