calcium, magnesium and phosphate metabolism

Question 1

why are Ca and Mg important

Answer 1

structure for teeth and bones
cofactor enzymes
used as intracellular signalling second messengers
neuromusclar muscle contraction and neurotransmitter release

Question 2

why is Po4 important

Answer 2

substrate for mineralisation
metabolism of sugars
ATp and GDP
help secrete H+ ions

Question 3

why is 2,3 DPG important

Answer 3

inorganic phosphate produced in red cells
binds to the beta chain of reduced haemoglobin (Hb), lowering Hb’s affinity for O2 and facilitating O2 release to tissues,

Question 4

Po4 and DPG

Answer 4

low Po4 reduces ability to form DPG
moves O2 curve to lefti increasing binding affinity for oxygen
results in inadqeuate o2 release at tisues

Question 5

calcium economy

Answer 5

bone is major pool for it

exchaned fromhere

Question 6

trabecular bone

Answer 6

spongy matrix structure

metabolic cyle occurs here

Question 7

osteoclasts

Answer 7

resorb bone and chomp it up

Ca, Po4 released

Question 8

osteoblasts

Answer 8

lay down new bone

Build it up

Question 9

bone anabolism

Answer 9

bone growth
laying down collagen and mineralisation
pos balance between things

Question 10

ageing bone

Answer 10

catabolism
negative balance
bone broken down more

Question 11

osteoporosis

Answer 11

metabolic bone dissease

bone mineral density falls

Question 12

calcium economy and the kidney

Answer 12

kidney filters blood ith calcium in and resorbs it

but high levels of blood Ca and damage kiney cels

Question 13

renal stones

Answer 13

high calcium through kidney leads to rena mechanism of stones forming
the calcium redicpiates into stones

Question 14

what facilitates the absoption of calcium

Answer 14

Vit D

Question 15

PTh

Answer 15

parathyroid hormone

also helps with calcium regulation

Question 16

role of PTh

Answer 16

parathyoid gland receptors detect falling ca and Mg

PTH made as pre-pro horone then cleaved to be biologically active

Question 17

PTH receptor

Answer 17

found in kidney
enzymatic region
makes cAMP
stimulates renal resoroption of calcium

Question 18

endocrine functions of Vit D

Answer 18

uregulates intestinal ca transport
more bone metabolism
more renal ca erabsoption
incerased blood pressure

Question 19

autocrine paracrine actions of vit D

Answer 19

inhibits cell proliferation
promotes cell differntiation
regulates immune system

Question 20

hyperparathyrodism

Answer 20

excess PTH

can be due to tumour

Question 21

consequences of hyperparathyrodism

Answer 21

• bones degraded, fractures
• kidney retains ca
• dilute urine
• kidney stones
• neuromuscular weakness

Question 22

hypocalamia

Answer 22

not enough vit D

can be caused by kidney failure, Mag deficiency, low PTH or vit D deficiency

Question 23

rickets

Answer 23

poor mineratlistion of bones and they become soft and bow under pressure

Question 24

role of PTH

Answer 24

• release more calcium from bone
• excrete less Ca from kdineys
• absorp more ca in gut