Biochemical role of calcium-

Calcium is the principle mineral and is an essential constituent of the cell and has following function in the body-
1) Calcium along with phosphorous is essential for the formation of the developments of bones and teeths.
2) Ionized calcium is required in blood coagulation process
3) It regulates the excitability of nerve fibers and nerve centers.
4) It is essential for nerve impulse and muscular contraction and regulates the permeability of membrances.
5) It is required for maintaing the integrity of intracellular material.
6) It is required for activation of several enzymes such as succinate dehydrogenase, ATPase and certain proteolytic enzymes.

Trace Elements-

These elements are present in living tissue in small amount. They are subdivided into three groups-
a) Eseential trace elements
b) Possibly Eseential trace elements
c) Non Eseential trace elements

Principal Element-

These includes calcium, magnesium, sodium, potassium, phosphorous, sulphur and chlorine.
Out of these, Na, K and Cl2 are involved mainly in the maintainance of acid base balance and osmotic control of water metabolism; Ca, P, Mg are the constituents of bones and teeth; phosphorous is a constituent of body cells of soft tissue, such as muscles, liver etc. sulphur in cysteine and methionine, thiamine, biotin and CoA.

Mineral Metabolim-

Mineral elements present in the body are supplied by the diet and are of two types-
· principal elements
· trace elements

Effects of dehydration-

1) Loss of weight due to the reduction in tissue water.
2) Disturbance in acid-base balance
3) Rise in nonprotein nitrogen of blood
4) Increased pulse rate and reduced cardiac output
5) Dryness, wrinklink and looseness of skin
6) Rise in body temperature due to reduction in circulating fluid.
7) Exhaustion and Collapse.

Dehydration due to injection of hypertonic solution-

When a highly concentrated sugar or salt solution is injected into the body, the osmotic pressure of blood increases. This result in the flow of fluid from the tissue into the blood until equilibrium sets in, consequently the blood volume increases. This increase blood volume soon returns the normal by to loss of excess material through excretion. This causes the net loss of body water producing dehydration.

Secondry dehydration-

The concentration of the elocrolytes of the body fluids are maintained constant through the elimination or reduction of water. The reduction or increase in the total electrolyte, which affects chiefly the basic radicals and is accompanied by a corresponding increase or decrease in the volume of body water. This causes intracellular edema. There is slowing of circulation and impairement of urinal function. The individual becomes weaker.

Primary dehydration-

a) Simple deprivation of water from desrt travel, extreme weakness and mental patients refusing to drink causes dehydration. It occurs more quickly in fever or in high temperature of the environment.
b) Excessive water loss due to vomiting, prolonged diarrhea, excretion of large quantity of urine or sweat.
In water depletion, the concentration of extracellular fluid increases. Water is drawn from the cells and both the extracellular and intracellular compartment shrinks. Extreme thirst result, the individual complains of hot and dry body, dry tongue.

What is dehydration-

When the lossess of water exceeds the intake of water, the body’s water content is reduced, that is, the body is in enegative water balance and this condition is known as Dehydration.

Properties of water-

1) Water is an extremely polar, hence is a good solevent.
2) It is a good insulator, hence controls the heat loss from the body.
3) Water has a very high dielectric constant.
4) Water shows hydrogen bonding with each other and variety of molecules such as protein, sugars, ions,etc.

Water is lost from body by the following routes-

1) Urine
2) Faeces
3) Perspiration
4) Evaporation from skin and lung

Water is supplied by body at following process-

1) Dietary liquid
2) Solid food
3) Oxidation of food stuff

Water balance-

Water is most common and abundant compound of all living system. An equilibrium is maintained between the intake and the loss of water from body. The regulatory mechanism of body water is influenced in addition to other factor by certain hormones, such as ADH oxytocin and aldosterone.

Heat regulation-

By virtue of its high specific heat, water prevents any significant rise in the body temperature due to heat liberated from body reaction. The loss of heat from the body is also regulated by the evaporation of water from skin and lungs and its removal in urine

Vitamin H-

Vitamin H is isolated from milk and named as Biotin. The carbonyl group of biotin combines with the terminal nitrogen of lysine residue of enzyme protein forming biocytin.
Biotin is concerned with carboxylation reaction. The biotin coenzymes apoenzyme complex attaches CO2 which is afterward transferred to other substances.

Co-enzymic activities of vitamin B6-

It is involved in the process of absorption of amino acids from intestine and in the desulphuration of cystein and homocysteine. It is required for the synthesis of amino levalinic acid which is an important intermediate in the synthesis of porphyrin and hemo nuclei.
It is also especially applied to brain metabolism because it is necessary for the formation of serotonin, amino butyric acid and the catecholamine. It is also concerned with immune response.

Biological function of pyridoxine-

Pyridoxine is essential for the growth of infants. Pyridoxine phosphate acts as coenzyme in transmination and decarboxylation af amino acids, interconversion of glycine and serine and transulfuration in methionine metabolism. Pyridoxine phosphate is required in the transport of amino acid and some metallic ions across the cell membrane. It is involved in the synthesis of co-enzyme-A from pantothenic acid is also concerned with immune response.