NCERT Revision Notes for Chapter 8 Body Movements Class 6 Science

Answer

• What is locomotion? 
• Parts of human skeleton 
• Types of joints in human body
• Bones and their various shape and functions 
• Cartilage
• Muscles
• Gait of animals:- earthworm, snail, cockroach, birds, fishes and snakes.

Answer

→ Locomotion is movement of the entire body from one place to another.

→ Locomotion forms a framework that gives shape and support to the body.

→ The human body consists of 206 bones.

→ Bones protect internal organs.

Answer

→ The bones present in our body form a framework this frame work is called Skeleton.

→ The human skeleton has two parts:

(i) The axial skeleton system: It includes the skull, vertebral column and the chest bones or the rib-cage.

(ii) Appendicular skeleton system: It includes hip girdles and shoulder and the limbs.

Answer

Different types of Joints

(i) Ball and socket joints

(ii) Pivotal joints

(iii) Hinge joints

(iv) Fixed joints

(i) Ball and socket joints

→ It is a type of joint in which ball shape surface of one bone fitted into the hollow space of another bone known as socket.

(ii) Pivotal Joints

→ Pivotal joints allow for flexibility, extension, rotation and twisting.

(iii) Hinge Joint

→ It is found between two or more than two bones where we need back and forth movement.

(iv) Fixed Joint

→ It does not move in any direction.

Bones

→ Skeletal structure is composed of hard material which is made up of calcium called bone

Various shape and functions of bones

→ The number of small bones on the back side these small bones combine called as backbone, which is helpful in bending front and back.

→ Bones which joins the chest and the backbone is called ribs

→ If you will touch just below your stomach area you will find the presence of pelvic bone.

→ The skull is the most hard and tough bone of our body which protects our brain from any mechanical injuries.

Cartilage

→ It is softer and more flexible than bone. Cartilage is found between the joints of knee and hips.

Answer

→ Muscles are attached to the bones and it is responsible for the movement of human body.

→ There is change in the length of muscle due to contraction and relaxation.

Answer

Locomotion of Earthworm

→ Earth worms commonly found in soil, it do not have bones. Their body is segmented, forms rings all over.

Locomotion of Snail

→ Snails commonly found on land or in soil.

→ It possesses wavy movement with muscular contraction.

→ Snail has hard shell on its back but it is not made up of bone and not helpful in locomotion.

Locomotion of Cockroach:

→ Cockroach is an insect and is a terrestrial animal mostly a common household pet.

→ The body is divided into three parts—head, thorax, and abdomen.

→ 3 pair of legs is present in thoracic part which moves by the muscles present near its limbs (legs).

→ The body is covered with the outer hard exoskeleton.

→ It uses breast muscles for the movement of wings due to which they can fly.

Birds

→ Birds were egg laying animal with feathers, wings and beak.

→ Fore limbs of birds were modified into wings due to which these can fly.

→ Hind limbs are legs due to which they can jump, walk or swim as can be seen in ducks.

→ The skeleton of birds is hollow to reduce weight and the breastbone muscle use to move the wings up and down.

Fishes

→ Fishes found in oceans, rivers, lakes, aquarium etc.

→ Fishes has well-arranged skeleton covered with strong muscles.

→ This movement is helped by the fins present on tail and also the fins presents on body helps to balance the body while swimming.

Snakes

→ Snakes live on ground, water, on trees. These were legless reptile.

→ During its movement snakes creates curves in many loops which pushes them to the forward direction, they moves very fast but not in straight-line the motion created by snakes is called serpentine motion.