Skeletal

Skeletal system

Presented by:-Soumya GuptaClass:-V-ASchool:-Mother Mary’s School, Mayur Vihar Phase-I, Delhi-110091.

What is a bone?

The skeletal system is made up of the bones and cartilage that

forms the framework of your body.

We have bones so that we are not a puddle of skin and guts on the

floor.

Babies have 300 bones.

Adults have 206 bones.

A bone is made up of salts, water, and tissue.Inside a bone there is a jelly substance called bone marrow.Bone marrow produces blood cells for the body.

The inside of the bone

Skull:-The skull protects the brain .The skull of an adult human being generally contains 22 bones.All bones in the skull are fixed, except the lower jaw. The movable lower jaw enables us to talk and eat. The upper and the lower jaws have teeth.

Different parts of human skeleton

Ribs are thin and curved bones that form a cage in the chest, called the rib cage.The rib cage protects our heart and lungs. .Most people have 12 pairs of ribs. .A long bone at the centre of the chest called sternum, holds the ribs from the front.The ribs are also attached to the backbone at the back. Last two pairs of ribs are not attached to the sternum are called floating ribs.

Rib cage

The backbone protects the spinal cord. It is made up of 33 small bones called vertebrae. The backbone is called the vertebral column.

Back bone

Upper Limbs:-The upper limbs have two parts.The upper arm is made up of a single bone, called the humerus .It is joined at the elbow to a pair of bones that form the lower arm. A number of smaller bones form the hand , which is attached to the lower arm.

LIMBS contd.

Lower Limbs:-The lower limbs have two parts.The upper leg is made up of a single bone called the femur, or the thigh bone. It is the longest bone in the human body. The lower leg is made up of two bones that join the femur at the knee.The feet are made up of a number of smaller bones.

limbs

Girdles are ring-like bony structures connecting the skull and vertebral column to the upper and the lower limbs. Types of girdles:- The shoulder girdle & the hip girdle.

Girdles contd.

The shoulder girdles connects the upper limbs to the body. It is made up of the collar bone and the shoulder blade . The hip girdles connects the lower limbs to the body.

Girdles

To protect our body and give it shape.To protect our internal organs.To provide a scaffolding for our muscles, allowing you to move.To store minerals until they are needed by the body.Produced blood cells in the bone marrow.

FUNCTIONS OF skeletal system

A joint is a place where two or more bones meet. Bones are held together at the joint by special tissues called ligaments. A tough, elastic called cartilage is also present on the surface of bones, at the joints.

joints

Ball and Socket Joint:-It allows movement in many directions.The shoulder joint and hip joint are examples of ball and socket joint.Hinge Joint:-It allows back and forth movement.. It works like the hinges of the door. Bones in the knee, elbow, fingers, and toes have this type of a joint.

Types of moveable joints

Pivot Joint:-

It allows you to move your head up, down, and sideways. It is found between the head and the first vertebra of your backbone .

Gliding Joint:-

It allows the bones to slide against each other in a gliding motion. It is found between the bones of wrist and ankle.

Cartilage and muscles

In addition to bones, cartilage and muscles also help us in movement.

Cartilage

:-It holds the bone together at the joints.Without cartilage, the bones would rub against each other and wear out.Ex:-Nose & Ears have cartilage.

Muscles

:-

Muscles

are

tissues that covers the bones.They are attached to the bones with the help of special tissues called tendons.

Thank you