Skeletal System

The skeletal system is composed of 206 bones joined and held together by connective tissues (Ligaments, Tendons , Fascia) to form a protective and supportive framework for the internal organs.

The function of the skeletal system is to enable the movement through a series of independently moveable levers.i.e. the bones , which the muscles can pull to different parts of the body. 

Bones aid movement by providing points of attachment for muscles and transmitting the force of muscular contraction form one part of the body to another during movement. 

Major Bones of the skeleton are :

The human skeleton is made up of 206 bones, including bones of the:
Skull – including the jaw bone
Spine – cervical, thoracic and lumbar vertebrae, sacrum and tailbone (coccyx)
Chest – ribs and breastbone (sternum)
Arms – shoulder blade (scapula), collar bone (clavicle), humerus, radius and ulna
Hands – wrist bones (carpals), metacarpals and phalanges
Pelvis – hip bones
Legs – thigh bone (femur), kneecap (patella), shin bone (tibia) and fibula
Feet – tarsals, metatarsals and phalanges.

There are 4 different types of bones :

Long Bone ,Short Bone ,Flat Bone  and Irregular Bone.

Long bone –  Examples include the bones of the arms and legs (excluding the wrists, ankles and kneecaps). It has long, thin shape.With the help of muscles, long bones work as levers to permit movement.

Short bone –Eg. bones that make up the wrists and the ankles.It has a squat, cubed shape.

Flat bone – Eg. ribs, shoulder blades, breast bone and skull bones.It has has a flattened, broad surface.

Irregular bone –  Eg. The bones of the spine (vertebrae). 

Vertebral Column : The Vertebral column also known as spine or spinal column.It is like a S shaped spring made of 33 bones known as vertebrae.It extends from the base of the skull through the entire length of trunk. It protects the spinal cord, supports the body and helps the body keep an erect posture.

Bone cells
Our body is constantly remodelling its skeleton by building up and breaking down bone tissue as required. As a result, each bone is rebuilt from scratch about every decade. The bone cells involved in this process include:
Osteoblasts – the cells that build bone tissue
Osteocytes – the cells that maintain bone tissue by controlling the mineral and calcium content
Osteoclasts – the cells that break down old bone tissue.

Bone tissue
The different layers of bone tissue include:
Periosteum – the dense, tough outer shell that contains blood vessels and nerves
Compact or dense tissue – the hard, smooth layer that protects the tissue within
Spongy or cancellous tissue – the porous, honeycombed material found inside most bones, which allows the bone to be strong yet lightweight
Bone marrow – the jelly-like substance found inside the cavities of some bones (including the pelvis) that produces blood cells.

Bone marrow
Bone marrow is where blood cells are made. The three different types of blood cell made by bone marrow include:
Red blood cells – carry oxygen around the body.
White blood cells – make up the body’s immune system.
Platelets – are used for clotting.

How to Improve Bone Density 
Eat Good amount of dietary calcium and Get adequate Vitamin D from food and sunlight. and do regular weight bearing exercise.   
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