CHAPTER-8 Body Movements

Human Body and its movements

  • Bone is a hard, grayish-white substance of which, two thirds is composed of inorganic matter or minerals like Calcium, phosphate, Carbonate which make the bone more brittle. The remaining one third is organic matter.
  • Bones are not solid. They have a strong outer layer of light weight compact bone which is spongy inside
  • In the centre a soft marrow which makes new Red Blood Cells(R BC) for the blood
  • Bones hav a strong covering like skin, this outer layer is called periosteum

S.No

Shape

Example

1

Long Bones

Bones of thighs,legs,toes,arm,forearm and fingers

2

Short Bones

Wrist and ankle

3

Flat Bones

Cranial bones,scapula clavicle and sternum clavicle

4

Irregular Bones

Vertebrae coccys and certain skull facial bones

 

S.No

Name of the joint

Nature

Example

1

Fibrous joints

Bones are held together fibrous connective tissue with no synovial cavity. These joints include immovable sutures

Skull bone between calf bone and tibia

2

Cartilaginous joints

Bones are held together by cartilage with no synovial cavity

Ear lobe, tip of nose, sternum

3

Synovial joints

All synovial joints are freely movable in selected directions and contain synovial cavity ,articular cartilage and a synovial membrane

Hip joint shoulder joint,elbow,elbow,atlas and axis ,tarsal bones

Skeleton

  • The adult human skeleton consists of 206 bones.They are classified into axial skeleton and appendicular skeleton.

Axial Skeleton

  • The vertebral column has a characteristic curve. It has five distinct regions.

They are listed below.

  1. Cervical Region (neck region) consists of seven vertebrae
  2. Thoracic Region (chest region) consists of twelve vertebrae
  3. Lumbar Region (Abdominal region) consists of five vertebrae
  4. Sacral Region (Hip region) consists of five vertebrae
  5. Coocygeal Region (vestigial region) consists of four vertebrae. They are rudimentary.

Ribs and sternum (Ribcage)

  • Protect the vital organs like lungs, heart, etc., There are twelve pairs ofribs.
  • The ribs at the sides, the sternum in the front and the backbones togetherform the “chest box”
  • The first seven pairs of ribs are directly attached to the sternum and are called ‘true ribs’
  • The next three pairs of ribs which are not directly attached to the sternum are called ‘false ribs’
  • The last two pairs (11th and 12th) are short and not connected to the sternum they are called ‘floating ribs’

Regions of the skeleton

Number of Bones

Axial

80

Appendicular

126

Total

206

 

Functions of the Skeletal  System

  • Support provideframe work and supports the soft tissue.
  • Protection: Many vital internal organs like brain, heart, lungs areprotected.
  • Movement facilitation: Serves as lever and helps to produce movement
  • Storage of minerals: Stores minerals like calcium, phosphate and carbonate.
  • Production of blood cells: Bone marrow produces the RBC, WBC andblood platelets.

More to know

  • The largest bone in the human body is the thigh bone or femer. In an average man, it is about 45 cm long.
  • The smallest bone is the Shapes, inside the ear.

Movement of Animals

Fish

  • Fishes live only in water. Their stream-line bodies are best suited for locomotion in water. Fins are locomotion organs
  • Most fish swim by waving their tails from side to side (eg. Tunny fish) .
  • Eels are fish with long bodies and moving with its whole body from side to side.
  • By moving certain fins, fish can change direction .They can go up or down, from left to right, or from right to left

Earthworms

  • The earth worm moves at the  rate of 25 cm per minute.
  • The nervous coordinates the activities of circular and longitudinalmuscles.

Cockroach

  • Cockroach is a swift runner as well as a flier.
  • The six legs are helpful in walking or running. When the cockroach is atrest, the coxae of the legs lie back against the body and the first legs are.directed forward.
  • The hind legs are stretched out posterior and the middle legs takewhatever position is convenient.

Snake

  • This S-shape movement also known as undulatory locomotion is used by many snakes on land and in water.

Birds

  • Birds are best suited for an aerial mode of life. The body is stream-linesand thus offers the least amount of resistance for movement in the air.
  • The reduced body weight facilitates easy flight. This is brought about bythe hollow (pneumatic) bones and air sacs in the cavity of the bone.
Scroll to Top