BODY MOVEMENTS
Joints –
Places where two parts of our body seem to be joined together.
Types of joints-
There are different types of joints in our body that help in carrying out different movements and activities. Some of them are：
1. Ball and socket joints –
- The joint in which part of the shoulder joined with arms.
- Such a joint allows movement in all directions.
2. Pivotal joints-
- The joint where our neck joins the head.
- It allows us to bend our neck forward and backward.
- Turns the head to our left or right.
3. Hinge joints-
- The elbow has a hinge joint.
- Allows only a back and forth movement.
4. Fixed joints-
- Joints where the bones cannot move.
- There is a joint between the upper jaw and the rest of the head which is a fixed joint.
Skeleton –
All the bones in our body form a framework to give a shape to our body, this framework is called the skeleton.
Carples-
Fingers are made up of several small bones called carples.
Rib cage-
- The ribs join the chest bone and backbone together to form a box, this is called the rib cage.
- There are 12 ribs on each side of the chest.
- It protects some internal parts of our body.
Backbone-
- It starts from the neck and ends at back our body.
- It is made up of many small bones called vertebrae.
- The backbone consists of 33 vertebrae and the rib cage is joined to these bones.
Shoulder bone-
- Two bones on The back where shoulders are present.
Pelvic bones-
- They enclose the portion of a body below the stomach, the part you sit on.
Skull-
- In this part of a body, many bones joined together.
- It encloses and protects our brain.
Cartilages-
- Additional parts of the skeleton are not as hard as the bones and can be bent.
Muscles –
Responsible for the movement of the human body. When contracted, the muscles become shorter, stiffer, and thicker.
Gait of animals –
Earthworm-
The body of an earthworm is made up of many rings joined end to end. It does not have bones. Earthworm first extends the front part of the body, then it fixes the part and releases the rear end.
Snail-
It carries a rounded structure at its back, this is called the shell. A thick structure and the head of the snail may come out of an opening. The structure of the foot made of strong muscles.
Cockroach-
The body is covered with a harr outer skeleton .outer skeleton is made of the number of plates joined together and that permits movement.
Birds-
The head and tail of the fish are smaller than the middle portion of the body, this body shape is called streamlined. The shape allows the fish to move in the water.
How do snakes move?
Snakes have:
- A long backbone.
- Many thin muscles.
- Muscles interconnect the backbone, ribs, and skins.
- The snake’s body curves into many loops. Each loop gives it a forward push by pressing against the ground.
Exercise
1. Fill in the blanks:
(a) Joints of the bones help in the __________ of the body.
(b) A combination of bones and cartilages forms the __________ of the body.
(c) The bones at the elbow are joined by a _________.
(d) The contraction of the __________ pulls the bones during movement.
(a) movement
(b) skeleton
(c) hinge
(d) muscles
2. Indicate ‘true’ and false’ among the following sentences:
(a) The movement and locomotion of all animals are exactly the same.
(b) The cartilages are harder than bones.
(c) The finger bones do not have joints.
(d) The forearm has two bones.
(e) Cockroaches have an outer skeleton.
(a) False
(b) False
(c) False
(d) True
(e) True
3)Match the following:
(i) Upper jaw (a) have fins on the body.
(ii) Fish (b) has an outer skeleton
(iii) Ribs (c) can fly in the air
(iv) Snail (d) is an immovable joint.
(v) Cockroach (e) protect the heart
(f) shows a very slow movement.
(g) have a streamlined body.
Ans –
(i) Upper jaw (d) is an immovable joint.
(ii) Fish (a) have fins on the body. & (g) have a streamlined body.
(iii) Ribs (e) protect the heart
(iv) Snail. (b) has an outer skeleton. & (f) shows a very slow movement.
(v) Cockroach. (c) can fly in the air
4.Answer the following questions:
(a) What are a ball and socket joint?
Ans: The joint in which part of the shoulder joined with arms. Such a joint allows movement in all directions.
(b) Which of the skull bones is movable?
Ans: Only lower jaws are movable.
(c) Why can our elbow not move backward?
Ans: Because the elbow has a hinge joint that allows movement in one direction only.
