Ist Dental Students - BioChemistry

2. Classification of minerals in
human body:
 According to body needs, minerals are divided:According to body needs, minerals are divided:
1-1-Major [MacronutrientsMajor [Macronutrients ]:]:
They are required in amountsThey are required in amounts > 100 mg / day> 100 mg / day..
They include:They include: calcium, phosphorus, magnesium,calcium, phosphorus, magnesium,
sodium, potassium, chloride and sulphur.sodium, potassium, chloride and sulphur.
2-2-Trace elements [Micronutrients]Trace elements [Micronutrients] ::
They are required in amountsThey are required in amounts < 100 mg / day< 100 mg / day..
They include:They include:
iron, copper, zinc, selenium, chromium, cobalt, iodine,iron, copper, zinc, selenium, chromium, cobalt, iodine,
fluoride, manganese and molybdenumfluoride, manganese and molybdenum..

3. Calcium& PhosphorusCalcium& Phosphorus

4. Ca DistributionCa Distribution
 1200 g1200 g of Ca in adult body.of Ca in adult body.
 99%99% in skeleton:in skeleton:
1. Major form1. Major form isis crystalline Ca phosphatecrystalline Ca phosphate ..
2. Minor form2. Minor form is amorphousis amorphous non-crystallinenon-crystalline CaCa
phosphatephosphate..
 1%1% in body fluids, serum and CSF:in body fluids, serum and CSF: ionized andionized and
non-ionizednon-ionized..

6. CaCa FunctionFunction
 Bone mineralizationBone mineralization::
Ca is an essential element inCa is an essential element in bone and teeth.bone and teeth.
Ca is captured into bones by bindingCa is captured into bones by binding
osteocalcin (osteocalcin (Ca binding protein).Ca binding protein).
 Ionized Ca:Ionized Ca:
1.1. Blood coagulationBlood coagulation and milk clottingand milk clotting..
2.2. Membrane permeability.Membrane permeability.
3.3. Muscle and Nerve excitability:Muscle and Nerve excitability:
-- Generation and conduction ofGeneration and conduction of nerve impulse &msnerve impulse &ms
contractioncontraction..
- Regulation of- Regulation of neuro-muscular excitabilityneuro-muscular excitability ..

7. CaCa
FunctionFunction
 Ionized CaIonized Ca::
4.4. Second messenger of many hormones:Second messenger of many hormones:
5.5. For activity ofFor activity of lipase, phosphorylase andlipase, phosphorylase and
αα- amylase enzyme.- amylase enzyme.

8. PhPh
DistributionDistribution
 800 g800 g distributed in all body cells.distributed in all body cells.
 80%80% inin bone and teethbone and teeth combined with Ca.combined with Ca.
 20%20% in all body cells as:in all body cells as:
10%10% inin (phospho compound)(phospho compound) phosphoproteins,phosphoproteins,
phospholipids and sugar phosphates.phospholipids and sugar phosphates.
10%10% inin (chemical compounds)(chemical compounds) as nucleicas nucleic
acids, nucleotides, coenzymes andacids, nucleotides, coenzymes and
creatine phosphate.creatine phosphate.

9. PhPh
FunctionFunction
 Bone and teethBone and teeth mineralization.mineralization.
 Phosphate esterPhosphate ester compounds forcompounds for
transfer and storage of energy.transfer and storage of energy.
 PhosphatePhosphate buffersbuffers system in blood.system in blood.
 Nucleic acidsNucleic acids formation.formation.
 Coenzymes [Coenzymes [TPP, NADP].TPP, NADP].

10. CalciumCalcium PhosphorusPhosphorus
SourcesSources Milk and its product, egg yolk,Milk and its product, egg yolk,
cabbage, cauliflowercabbage, cauliflower
AbsorptionAbsorption Active transport in upper S.I byActive transport in upper S.I by
CBP.CBP.
Ca:P ratio in diet 1:1 (adults) andCa:P ratio in diet 1:1 (adults) and
1.5:1 (infants).1.5:1 (infants).

11. Factors affecting absorption
 1-Calcitriol (1,251-Calcitriol (1,25
dihydroxycholecalciferol):dihydroxycholecalciferol):
It is produced inIt is produced in
the kidneys in response tothe kidneys in response to lowlow plasma Ca.plasma Ca.
↑↑ intestinal absorption of calciumintestinal absorption of calcium &&
phosphorus through;phosphorus through;
mechanism :-mechanism :-↑↑ synthesissynthesis Calcium BindingCalcium Binding
ProteinProtein >>>which is responsible for Ca>>>which is responsible for Ca
absorption through the intestinal mucosalabsorption through the intestinal mucosal
cell.cell.

12. Factors affecting absorptionFactors affecting absorption
(cont(cont.(.(
 2-PTH:2-PTH: through activation of vit D.through activation of vit D.
 3-pH3-pH of intestinal contents.of intestinal contents.
Alkaline pHAlkaline pH leads to less soluble Ca saltsleads to less soluble Ca salts
Acidic pHAcidic pH favours Ca solublity andfavours Ca solublity and
absorption.absorption.

13. Factors affecting absorptionFactors affecting absorption
(cont(cont.(.(
 4-Dietary factors:4-Dietary factors:
For optimal absorption CaFor optimal absorption Ca++++
: PO: PO--
44 ratio inratio in
diet is 1:1 in adult and 1.5 : 1 in infant.diet is 1:1 in adult and 1.5 : 1 in infant.
A-A- Vit D, lactose and high protein dietVit D, lactose and high protein diet ↑↑
the absorption.the absorption.
B-B- Phytate, oxalate (insoluble Ca salts)Phytate, oxalate (insoluble Ca salts)
and fatty acids (insoluble Ca soap)and fatty acids (insoluble Ca soap) ↓↓ CaCa
absorptionabsorption while aluminum hydroxidewhile aluminum hydroxide
(antacid)(antacid) ↓↓ Ph absorption.Ph absorption.

14. Blood calcium & phosphorusBlood calcium & phosphorus
CaCa PhPh
Plasma level isPlasma level is
9-11 mg/dl9-11 mg/dl
diffusible:diffusible:
ionized: 50% (active)ionized: 50% (active)
non ionized: 5%non ionized: 5%
(inactive Ca citrate)(inactive Ca citrate)
 non diffusible:non diffusible:
protein bound [45%].protein bound [45%].
Plasma level isPlasma level is
4-7 mg/dl in child &4-7 mg/dl in child &
3-4.5 mg/dl in adult3-4.5 mg/dl in adult
Ca : P ratioCa : P ratio is importantis important
in ossificationin ossification
In serum, the ionic productIn serum, the ionic product
of Caof Ca ×× P is about 50 mg/dlP is about 50 mg/dl
in children (in children (↓↓ in rickets)in rickets)

15. Control of blood calcium &Control of blood calcium &
phosphorusphosphorus
o The precise control is regulated by action ofThe precise control is regulated by action of PTHPTH,,
calcitriolcalcitriol andand calcitonincalcitonin on intestine, kidney andon intestine, kidney and
bone.bone.
 1-Calcitriol:1-Calcitriol:
produced in kidney in response toproduced in kidney in response to
lowlow calcium & phosphorus level.calcium & phosphorus level.
It increases calcium level by:It increases calcium level by:
 Increasing theirIncreasing their intestinal absorptionintestinal absorption andand renalrenal
tubular reabsorption of Calcium .tubular reabsorption of Calcium .
 StimulateStimulate bonebone resorptionresorption..

16. Control of blood calcium &Control of blood calcium &
phosphorus (cont.)phosphorus (cont.)
2-PTH:2-PTH:
secreted in response tosecreted in response to low plasma calciumlow plasma calcium level.level.
ItIt ↑↑ calciumcalcium && ↓↓ phosphorusphosphorus levels through;levels through;
 ActivatesActivates vitamin D>>>calcitriol.vitamin D>>>calcitriol.
 IncreaseIncrease intestinal absorptionintestinal absorption of both in presence ofof both in presence of
calcitriol.calcitriol.
 Increases mobilization of both Ca&P fromIncreases mobilization of both Ca&P from bone tobone to
bloodblood..
 IncreasesIncreases renal tubular reabsorption of Carenal tubular reabsorption of Ca++++
andand
increases phosphate excretionincreases phosphate excretion..

17. Control of blood calcium &Control of blood calcium &
phosphorus (contphosphorus (cont.).)
 3-Calcitonin:3-Calcitonin:
lowerslowers both plasma calcium andboth plasma calcium and
phosphorus by:phosphorus by:
 inhibiting mobilization from bone.inhibiting mobilization from bone.
 DDecreasing calciumecreasing calcium renal tubular reabsorptionrenal tubular reabsorption
of calciumof calcium & phosphorus ( increases Ca and Ph& phosphorus ( increases Ca and Ph
excretion).excretion).

18. The total body iron of an adult (70 kg) isThe total body iron of an adult (70 kg) is
about 4-5 g. It is distributed as followsabout 4-5 g. It is distributed as follows::
Heme iron compoundsHeme iron compounds
 HemoglobinHemoglobin
 MyoglobinMyoglobin
 Cytochrome CCytochrome C
 Cytochrome aCytochrome a11, a, a33, b, b
 PeroxidasePeroxidase
 CatalaseCatalase
Non heme iron compoundsNon heme iron compounds
 FerritinFerritin
 HemosiderinHemosiderin
 TransferrinTransferrin
Other iron compounds (<5%) is mainly present
bound to proteins

19. Biological functionsBiological functions
 Iron enters in the structure of:Iron enters in the structure of:
- hemoglobin- hemoglobin
& myoglobin. .& myoglobin. .
- cytochrome P- cytochrome P450450..
- peroxidase and catalase.- peroxidase and catalase.
- thyroperoxidase.- thyroperoxidase.

20. Disorders of plasma iron levelDisorders of plasma iron level
Iron deficiency anemiaIron deficiency anemia..
HaemosiderosisHaemosiderosis..

21. Iron deficiency anemiaIron deficiency anemia
Inadequate intake.Inadequate intake.
Impaired absorption:Impaired absorption:
-achlorhydria.-achlorhydria.
-steatorrhea.-steatorrhea.
-intestinal resection.-intestinal resection.
Excessive blood loss.Excessive blood loss.
 ↓↓ Plasma iron.Plasma iron.
 ↑↑ transferrin.transferrin.
 RBCs isRBCs is hypochromic,hypochromic,
microcyticmicrocytic..

22. Haemosiderosis
 repeated blood transfusion.repeated blood transfusion.
 overdose of injectable iron.overdose of injectable iron.
 congenital abnormality of increasedcongenital abnormality of increased
iron absorption.iron absorption.

23. Flouride
 SourceSource: drinking fluorinated water, sea fish.: drinking fluorinated water, sea fish.
 FunctionsFunctions::
- protective against- protective against dental cariesdental caries (↓incidence(↓incidence
of dental caries of up to 70%).of dental caries of up to 70%).
- protective against- protective against bone demineralizationbone demineralization
disorders, asdisorders, as osteoporosis and osteomalaciaosteoporosis and osteomalacia..