based on your knowledge of tissues explain how sufficient di

based on your knowledge of tissues, explain how sufficient dietary intake of calcium would ensure the normal development of bone.

Solution

ANS:

Calcium is the most abundant among the minerals in the body. Adult man contains 1 to 1.5 kg calcium and 99% of calcium is present in bones and teeth.

Physiological mechanism of calcium in normal development of bone:

Bone formation is also known as osteogenesis. this process starts at 8th week of embryo. Bone tissue replaces a precursor embryonic tissue to form the skeleton. So the need of calcium is very important in this process of ossification, it occurs throughout life when bone has happened any damages.

The prenatal bone formation divides into 2 parts

A. Intra-membranous ossification ( occurs in many bones of skull)

B.  Endochordal ossification (occurs in rest of the body)

A. Intra-membranous ossification

it is divide divided into 4 stages

1.Ossification center developed in Fibrous connective tissue:

The bones is generated on or within the fibrous connective tissue membrane. The embryonic mesenchymal cells differentiates into osteoblasts and this region is called ossification center.

2.Calcification or Osteocytes mineral salts deposition:

The osteoblasts begin to secret osteiods (bone matrix) and become osteocytes.

The osteocytes are bone maintenance cells that promote deposition of calcium salts.

In this stage the calcium and phosphorus are highly deposited and hardens the matrix.

3.Trabecules Formation:

The bone matrix develop thin column bone called Trabecules. and this Trabecule fused to formed spongy bone.

4.Development of periosteum, spongybone and compact bone tissue:

In this the blood and lymphatic vessels grows into the surface of newly formed bone and develop

red bone marrow. outside of the bone a dense connective layer formed and it is called as aperiosteum.

Most of the outer layer of spongy bone is replaced by compact bone. but the center remains spongy.

The daily requirement of calcium is depends on age.

Age                          Daily Recommended Allowance

Infants                                   250 mg/day

Children 1- 3 years 700 mg/day

Children 4- 8 years 1000 mg/day

Children 9- 18 years 1300 mg/day

Adults 19- 50 years 1000 mg/day

Adults Male 51- 70 years 1000 mg/day

Adults Female 51- 70 years 1200 mg/day

Calcium Recommended in pregnancy:

Around 30 mg of calcium is deposited in fully grown fetus. so an intake of 1 gram calcium/day meets the needs of mother.

Calcium Recommended in Lactation:

Human milk contains 30- 40 mg cal/100 ml. So for 850 ml around 300 mg cal secreted /day through milk. so an intake of 1 gram calcium/day meets the needs of mother.

Calcium Recommended in school age:

10- 12 Years child require more calcium than adults, because the skeletal growth is very high when compare to other stages.

Calcium Source:

Best Source: Milk and Milk products.

Good Source: Beans, Leafy vegetables, Fish, Cabbage and Egg yolk.