Class 06 || Science || Ch. 08. Body movement

Class 06 || Science || Ch. 08. Body movement

Q. What do you mean by The skeleton aur skeletal system?

Ans. The framework formed by the bones of the body is called the skeleton. This framework provide a shape to our body.

The whole framework of the bones of the body is also known as the skeletal system.

Skeleton is made up of three types of components which are many bones, joints and cartilage.

Q. What do you mean by the movable and fixed joint?

And. Where two parts of our body seems to be jointed together are called joints, like elbow, shoulder or neck. 

(i) Movable joints and 

(ii) Immovable or Fix joints

(i) Moveable joint: The joints where movement of bones is possible are called movable joints.

(ii) Immovable or Fix joints:– The joints where no movement of bones is possible are called fixed joint. The joints in the skull bone (cranium) is examples of fixed or immovable joints.

Q. What do you mean by the joints? What are the main types of the joints? Explain with example.

Ans. Jaints:-  Where two parts of our body seems to be jointed together are called joints, like elbow, shoulder or neck. 

There are three different types of the joints in our body.

1. Ball and Socket joints

2. Pivotal jaints 

3. Hinge joints

4. Fixed joints

5. Gliding joints

1. Ball and Socket joints :- The joint where a ball is fitted into a cavity like socket, this type of joints are called ball and socket joints.

Such as the hip joint, in which a partially spherical end lies in a cavity or socket.

2. Pivotal joints :- Joint that allows only rotary movement around a single axis are called Pivot joint or rotary joint, like joint of head and neck.

The moving bone rotates within a ring that is formed from a second bone and adjoining ligament.

The joint of skull with backbone ardha examples of Pivot joints.

3. Hinge joints :- Joints that allows movement in one direction. Like The hing of a door so that it is called hinge joint.

Like that joints of elbow, fingers and knee.

4. Fixed joints: Those joints which do not allow movement are called fixed joint.

Joint of cranium skull are fixed joint.

5. Gliding joint: These joints allow only a limited amount of movement of sliding nature of cartilage. For example, the joints of backbone.

Q. What are ribs?

Ans: The bones of the chest are called ribs.

Q. What is rib cage?

Ans. The ribs are curiously bent bones of the chest. A case like structure is formed by joining the chest bones (rib) and the backbone together is called the rib cage. It protects our internal organs of our body inside this cage. 

Q. Name of the organs that are protected by the rib cage?

Ans: Heart and Lungs.

Q. What is backbone?

Ans. A long and hard structural row of small bones that connected together starting from the neck and move down the middle of back is called backbone. The rib cage is joined to these bones.

It is made of many small bones which make us capable to bend or move. If backbone is made up of only one long bone then we will not be able to bend or move. 

Q. What do you mean by the shoulder bone?

Ans. The bones standing to form the shoulder are called shoulder bones.

The shoulder bones are formed by the collar bone and the shoulder blade. It also connects the upper part of the chest and bones of the arm.

Q. What are pelvic bones?

Ans  The enclose portion of the hip of our body below the stomach on which we sit on. This structure of the hip is made up of pelvic bones. 

The bones enclose the body part below the stomach. 

Q. What is cavity in bone?
Ans:  The hollow or pit like space in the bone is called cavity.

Q. What do you mean by fractured bone? Why are fractured bones plastered?
Ans: Fractured bone means the broken bone.

Plaster checks the movement between broken parts and keeps broken bones at their right place so that they join properly.

Q. What are bones?

Ans: The hard, strong and non flexible internal part of the body d is known as bone.

Bones are hard and shows inflexibility so that a bone cannot be bent.

Q. What are cartilages?

Ans: Some parts of the skeleton are not as hard as bones and shows elasticity and can be bent are called cartilages, e.g. cartilage of ear.

Q. Write the differences between bones and cartilage.
Ans:  

Bone	Cartilage
(i) They are hard.	(i) They are soft.
(ii) They cannot bend.	(ii) They can bend.
(iii) They are used to make the framework of whole body.	(iii) They help to make some parts of the body.

Q. How can you know about the shape of human skeleton?
Ans:
(i) We can know the shape of skeleton by feeling of tuch.

(ii) We could know the shape by X-ray images of human body

Q. What do you mean by movement?

Ans:  The changing position or any part of the body is called movement.

Q. Why do we need two types of muscles together to move a bone?
Ans: A muscle can only pull, it cannot push. Thus, two muscles are required to work together to move a bone. When one muscle contracts, the bone is pulled. When another group of muscle of the pair pulls, it brings the bone in its original position.

Q. How do the muscles work?

Ans: Mind it that a muscle can only pull. It cannot push. 

The muscles work in two groups. When one of them contracts, the bone is pulled in desirable direction, the other group of muscle relaxes at this time. 

At the time of movement of the bone in the opposite direction, the relaxed group of muscle contracts to pull the bone towards its original position, while the other one group relaxes. 

Q. Many people suffer from a problem called arthritis. Explain its connection with movement.
Ans: Arthritis is the pain in joints. With this problem people find difficulty in moving from one place to another.

Q. How does the earthworm move?
Ans:  Earthworm does not have bones. It has muscles which help to extend and shorten the body during movement. 

At the time of the movement, earthworm first extends front part of the body keeping the rear portion fixed to the ground. Then it fixes the front and releases the rear end. 

It then shortens the body and pulls the rear end forward. This makes it move forward by a small distance.

In this way by repeating such muscular expansions and contractions earthworm moves. The body secretes a slimy substance to help the movement.

Q. How the earthworm moves under the ground?

Ans. Earthworm has a large number of tiny hair like structures called   bristles  projecting out of the body. The bristles are connected with muscles and help to get a good grip on the ground.

Q.  How the the earthworm make the soil fertile?

Ans. The earthworm, actually, eats its way through the soil and throws away the undigested part of the material that it eats. This activity of an earthworm makes the soil more useful for plants.

It increase the fertility of the soil so that the earthworms are called the friends of the farmers.

Q. How does the snail move?
Ans: The rounded structure on the back of the snail is called shell. It is the outer skeleton (exoskeleton) of snail. 

When it starts moving a thick structure of the body, the head of the snail come out of an opening in the shell. The thick structure is called foot, made up of strong muscles. It helps snail in moving. It fix the foot and then dreag the shell. This makes it move forward by a small distance.

Q. How the cockroach moves?

Ans. Cockroaches walk, climb as well as fly in the air. They have three pairs of legs to walk. The body is covered with a hard outer skeleton.

The cockroaches have distinct muscles near the legs helps to move the legs for walking. There are two pairs of wings attached to the breast. The breast muscles move the wings to flies.

Q. What do you mean by streamlined ?
Ans: If the shape of the body is smaller at both the ends than the middle portion of the body like boat is called streamlined.

The shape of a boat, fish and birds are streamlined.

The streamlined shape can flow around it easily and allow the fish to move in water.

The head and tail of the fish are smaller than the middle portion of the body the body tapers at both ends. This body shape is called streamlined.

Q. How is a bird’s body adapted for flying?
Ans: Birds can fly in the air and walk on the ground. Some birds like ducks and swans also swim in water. 

The birds can fly because their bodies are well adopted for flying. Their bones are hallow and light. The bones of the hind limbs are typical for walking and perching. The shoulder bones are strong. The bony parts of the forelimbs are modified as wings. 

The breast bones are modified to hold muscles of flight which are used to move the wings up and down.

In short we can say that the following adaptations are seen in the body of birds.
(i) Bones are hollow.
(ii) Forelimbs are modified into wings.
(iii) Body is streamlined.

Q. How does fish move in water?

Ans: The body of fish is streamlined. The streamlined shape is such that water can flow around it easily and helps and allow the fish to swim in water. 

The skeleton of the fish is covered with strong muscles. During swimming, muscles make the front part of the body fish curve to one side and the tail part swings towards the opposite side. 

The fish forms a curve as shown in Figure. Then, quickly, the body and tail curve to the other side. This makes a jerk and pushes the body forward. A series of such jerks make the fish swim ahead. This is helped by the fins of the tail.

Q. How does the snake move?

Ans: Snakes have a long backbone and many thin muscles connected to each other which help in the movement. These muscles are also interconnected the backbone, ribs and skin.

The snake curves their body into many loops. Each loop of the snake gives it a forward push by pressing against the ground.

 

Large number of loops form large push, by this the snake moves forward very fast and not in a straightline.

Q. What do you know about the Gait of Animals?

Ans. The 'Gait of Animals' is the name of a book which was written by the ancient Greek philosopher Aristotle. 

In his book he asked himself so many questions the movement of the animals. 

Q. Can bones be bent?
Ans:  No, bones cannot be bent.

Q. Which parts of the body help in movement.
Ans: Contraction and relaxation of muscles, bones and joints help in movement.

Q. Write the name of an animal which can walk, climb and fly in the air.
Ans: Cockroaches.

Exercise

Q. 1. Fill in the blanks:

(a) Joints of bones help in the _________ of body.

(b) A combination of bones and cartilages forms the _________ of the body.

(c) Bones at the elbow are joined by a _________ joint.

(d) The contraction of the _________ pulls the bones during movement.

Ans. (a)  movement , (b) skeleton, (c) hinge, (d) muscle

Q. 2. Indicate true (T) or false (F) for the following sentences.

(a) Movement and locomotion of all animals is exactly the same. ( )

(b) Cartilages are harder than bones. ( )

(c) Finger bones do not have joints. ()

(d) The fore arm has two bones. ( )

(e) Cockroaches have an outer skeleton. ( )

Ans.

(a) False; Movement and locomotion of animals is not same, but it depend up on their body structure. So, animals with different body structure need different modes of movement.

(b) False; Cartilages are not as hard as bones but it is soft and can be bent easily.

(c) False; Finger bones also have joints.

(d) True.

(e) True

Q. 3. Match the items in Column I with one or more items in Column II.

Column I       Column II

Upper jaw      *have fins on the body

Fishes            *has an outer skeleton

Ribs                *can fly in the air

Snail               *is an immovable joint

Cockroach     *protect the heart

                         *shows very slow 

                          movement

                         *have a streamlined 

                            body

Ans.

Correct matches of column I with column II are given below:

Column I      Column II

Upper jaw    *is an immovable joint

Fishes          *have a streamlined 

                         body; 

                      *have fins on the body

Ribs              *protect the heart

Snail             *shows very slow 

                         movement

Cockroach   *has an outer skeleton; 

                      *can fly in the air

Q. 4. Answer the following:

(a) What is a ball and socket joint?

Ans. Ball and Socket joints :- The joint where a ball is fitted into a cavity like socket, this type of joints are called ball and socket joints.

Such as the hip joint, in which a partially spherical end lies in a cavity or socket.

(b) Which of the skull bones are movable?

Ans. Lower jaw bone (Mandible bone) is the only skull bone which is movable.

(c) Why can our elbow not move backwards?

Ans. Our elbow cannot move backwards because it has a hinge joint which allows the movement only in one direction.