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.
- Cervical Region (neck region) consists of seven vertebrae
- Thoracic Region (chest region) consists of twelve vertebrae
- Lumbar Region (Abdominal region) consists of five vertebrae
- Sacral Region (Hip region) consists of five vertebrae
- 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.