Functions of calcium
This is the most abundant mineral found in the skeletal and bone tissues. Approximately 1200g of calcium is found in our body, of which 99% is combined as salts- mainly as calcium phosphate- which give hardness to the bones and enable them to hold the weight of a body.
The remaining one percent performs the following function:
- It catalyses the clotting of blood. Injury to a cell is taken care as follows:
Blood platelets in presence of calcium are converted to Thromboplastin
Thromboplastin + prothrombin to Thrombin
Thrombin + Fibrinogen in presence of calcium are converted to Fibrin (the clot)
2. It activates several enzymes such as pancreative lipase, adenosine phosphatase and some proteolytic enzymes.
3. It is necessary for synthesis of acetylcholine,a substance that is necessary for transmitting nerve impulses.
4. It helps to absorb vitamin B12 in the ileum.
5. Its vital function is to regulate contraction and relaxation of muscles including beating of heart.
6. It helps the absorption process by increasing the permeability of cell membranes.
Deficiency of calcium
- Severe deficiency of calcium leads to Rickets in children and Osteomalacia in adults.
Rickets – seen more often in premature infants than in full term infants as their growth and calcification rate demand more calcium and vitamin D.
The characterstics of rickets
- Are delayed closure of fontanelles, bulging or bossing of forehead and soft and fragile bones.
- There may be bowing of the legs or knock knees if there is enlargement of wrist, knee and ankle joints.
- Muscle development is poor and walking may be delayed.There may be restlessness and nervous irritability.
- Rachitic rosary is seen in the breast region as enlargement of the costochondrial junction.Projection of sternum causes pigeon breast.
Osteomalacia – Softening of the bones may be seen in women due to repeated pregnancies and low intake of Vitamin D and calcium.
It can also be seen in patients suffering from diseases with interference in fat absorption and in patients with renal disease.
The characterstics of osteomalacia
- Softening which usually takes place in the bones of legs, spine, thorax and pelvis,which may bend and show deformities.
- Other symptoms are-Rheumatic -type pain in bones of legs and lower part of back
- General weakness, especially while walking and climbing stairs
- Spontaneous multiple fractures.