Calcium fnal
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Transcript of Calcium fnal
•Minerals
• 29 different types of elements in our body.• Divided into 4 Major Groups
• Group I:- C, H, O, N- Component of Macromolecules such as Carbohydrates, Proteins and Lipids
• Group II :- (Macro Elements)- Includes., Na , K , Cl ,Ca , P , Mg & S- Required in amount > 100 mg/day- Deficiency leads to fatal complications/death
• Group III :- (Trace Elements)
- Required in amount < 100 mg/day
- Includes., Co (Cobalt), Cr (Chromium), Cu (Copper), I (Iodine), Fe (Iron), Mn (Manganese), Mo (Molybdenum), Se (Selenium) & Zn (Zinc)
• Group IV:- (Additional Trace Elements)
- Exact role is unknown
- Cd (Cadmium), Ni (Nickel), Sn (Stensium),
Vn (Vanadium)
Metabolism of MineralsCommon minerals found active in body are
Na+, K+, Cl, Ca++ Fe++, P, Mg++, etc. Ca++, P, Mg, Constituent of bones and teethFe++:- Important element present in heme
compounds such as Hb , Cytochromes etc.Deficiency of Minerals result in disturbance
of Physical Structure, Metabolic processes and Normal functioning of body
• GENERAL FUNCTIONS OF MINERALAS1. Structural components of body i.e., They
perform building function e.g., Ca, P are used in Bone formation, F for Teeth, P, K, Cl & S for Tissues. S also for Hair, Nail; Fe for Hb; Cl for HCl secretion & I for Thyroid Hormones.
2. Acid/Base Balance:- [NaH2PO4/NaHPO4]
3. Regulates body fluids e.g in H2O Balance4. For the transport of Gases5. Responsible for Contraction & Relaxation6. As a Co-factor of certain Enzymes
CALCIUMCALCIUM
Dietary SourcesDietary Sources• Milk and milk product------Best dietary source• Other good Sources are Egg yolk, Beans, Nuts
& hard drinking water .• Leafy vegetables:- (also contain oxalate &
benzoate), which are insoluble and thud decrease its absorption
Body Distribution
• Human body contain about 1 Kg Ca2+
• 99 % in bones
• 1 % in extra cellular fluid .
Bone Ca2+:
In form of Hydroxyappetite Crystal [(Ca)6(PO4)3(OH)]
Bones perform two main functions:-
1. Mechanical Functions
2. Reservoir of Ca2+
1 % of bone Ca 2+ & 1 % of periosteal space Ca2+ is freely exchangeable with E.C.F & this is called Miscible Pool of Ca2+
This exchange is regularized by P.T.H, Calcitriol,
& also by Calcitionin
Calcium in Plasma
[9 – 11 mg /dL]
R.B.C contains very little Ca2+
Extracellular concentration = 5m mol/L
Intracellular concentration = 0.1 – 10 µ mol/L
Ca2+ in plasma Exists in 3 forms
A. Protein Bound Ca2+ [47%]
Mostly albumin (80%), Serum globulin (20%) and
Normal Level is 3.4 – 4.4 mg/dL
B. Complex Calcium [6%]
Complexed with plasma anions e.g., Citrate & Phosphates etc. (0.5 – 0.7 mg/dL)
C. Ionized, Diffusible or Free Ca2+ [47%]
Biologically active from
• All 3 forms of Ca2+ in plasma remain in equilibrium with each other
• Solubility product of Ca2+ i.e., Ca x P in serum is a constant value
• It gives protection against precipitation of Ectopic Calcification
Absorption:
• Ca2+ is taken in diet principally as calcium phosphate, carbonates & tartarate.
Only 40% of dietary Ca2+ is absorbed mainly from duodenum & first half of jejunum against electrical and concentration gradients
Mechanism:
Two mechanisms for absorption
1. Simple diffusion
2. Active transport process
Both the process required Calcitriol and also a Ca2+ dependent ATPase
Vitamin – D
Vit. D2: Ergocalciferol (Vegetables)
Vit. D3: Cholecalciferol (Animals origin/Inactive)
25 – Hydroxylase (Liver)
25–Hydroxycholecalciferol (Inactive)
1- α Hydroxylase
1, 25–Dihydroxy-Cholecalciferol/Calcitriol
(In Kidney)
Factor affecting absorption of Ca2+:
1. pH of Intestine Acidic pH favors/increases absorption because
Ca2+ salt particularly PO4-3, carbonate are quite
soluble in acidic solution. Alkaline pH decreases the absorption due to
form-ation of insoluble Tricalcium PO4-3
2. Composition of Diet High protein diet: Increases absorption
because a.a (lysine & arginine) increases solubility of Ca2+ salt
F. Acids decreases insoluble calcium soap Sugars & organic acids increases absorption Phytic acids decreases absorption Oxalates present in vegetables also decreases
the solubility & hence decreases its absorpt.
3. Minerals
a) PO4-3: Excess of PO4
-3, decreases Ca2+ absorption
b) Ca:P Ratio: For optimal absorption of Ca2+ ideal ratio of Ca2+ to PO4
-3 is 1:1 and it should not be more then 2:1 and not less than 1:2
c) Fe in diet: forms insoluble Ferric phosphates which decrease absorption
d) Vit–D: Increases absorption & serum Ca2+ level
4. State of Health & Aging:
- Healthy adult= 40% of dietary Ca+2
- above age of 60 years there is a gradual decline
- Ca+2 deficiency increases absorption probably through increase Parathyroid activity
e) Bile salts: Increases Ca2+ absorption by
i. Enhanced solubility of Ca2+ salts
ii. Increases Vit–D absorption
iii. Increases Digestion & absorption of fats
5. Hormones
(A) P.T.H:
1 Stimulates “1-α Hydroxylase’’ enzyme in kidneys & increase synthesis of Calcitriol which increase Ca2+ absorption from gut
2 Direct effect on bone
3 Direct effect on kidney.
(B). Calcitonin:
Increased level inhibits “1-α Hydroxylase’’ & decrease calcitriol synthesis & decrease Ca2+ absorption. Used in treatment of Hypercalcaemia caused by hyperparathyroidism & Vit–D intoxication
(C) Glucocorticoids:
Decrease Ca2+ absorption by decrease intestinal transport of Ca2+
• Factors affecting plasma Ca2+ Levela. Amount of Ca2+ absorbed from GITb. P.T.Hi. Increases mobilization of Ca2+ from bones
(Largest Effect)(ii) Increase absorption in gut (Long Term Effect)
(Increase the synthesis of Calcitriol)(iii) Decrease execration by kidney (Most Rapid
Action) c. Inverse relationship b/w plasma Ca2+ & Pi. When
plasma Ca increase, P decrease & vice versa so product of plasma Ca2+, & Pi remain constant at 30–40 mg/dL in adult 40–55 mg/dL in children.
[Plasma Ca2+ level falls in kidney diseases due to retention of PO4
-3 so increase PO4-3,
decreases Ca2+]
d. Serum Protein Level: 1 gm serum protein bound 0.84 mg of Ca2+. However ionized Ca2+ remain normal so there will be no Tetany, when there is deficiency of protein
e. Calcitonin: It decrease serum Ca2+ by antagonizing the action of PTH. It decrease bone resorption & increase deposition of Ca2+ in bones (It inhibits 1-α Hydroxylase)
Mechanism of action of Calcium:
Intracellular Ca2+ binds Calmodulin (4 binding Sites)
Ca–Calmodulin Complex
Active Calmodulin Kinase
Catalyze formation of Phosphoprotein from Protein [Phosphoprotein exert their
Physiological & Biological response]
• Functions of Calcium1. Calcification of Bones and Teeth2. Play imp. Role in Blood Coagulation3. A number of enzymes are activated by
blood Ca2+ e.g., Lipase, Succinic dehydrogenase & few Proteolytic enzymes
4. Play role in muscle contraction5. Transmission of nerve impulse6. Help in acid base balance7. Essential for release of certain hormones &
also for intracellular action of certain hormones
8. Essential for permeability of gap–junction
9. Membrane integrity & membrane transport
Excretion
Mainly excreted in faeces (0.4–0.8 g/day) , which is unabsorbed form. Urinary loss is 150 – 200 mg/day. Men working in extreme heat may loss 100 mg/hr of Ca2+
Requirement: [1g/day]
Increase in pregnancy, lactation, & in children
• Hypercalcaemia: Various causes
• Ca get deposited in various body tissues resulting in their malfunction
• Hypocalcaemia:
Low plasma ionized Ca2+:--- Tetany, characterized by spontaneous firing of Nerve fiber. Increase Cardiac contractibility, retardation of relaxation of muscles etc. Corpopedal Spasm
If untreated my lead to death. Spasm due to respiratory muscles. I/V Calcium is treatment