CBSE Class 6 Science Notes Chapter 8 Body Movements

Learn from School Connect Online in this chapter we will learn the things,like  our garden has different varieties of plants like grasses, bushes, flowering plants and tall coconut trees. In this chapter we will learn how to classify them in categories?Body Movements Class 6 notes – Chapter 8 – School Connect Online

Chapter : 8 – Body Movements

The different topics covered in CBSE Class 6 Science Chapter 8 are tabulated below:

Ex : 8.1 – Human Body and Its Movements

Movement :

Body movement is something that gets polished as we grow in age. In our childhood, we tend to start with basic movements such as rolling, crawling and eventually walking.

Skeletal System

• Bones in our body form the framework that supports the whole body. This framework is called the skeleton.
• Our skeleton is made up of a number of bones and cartilages.
• There are about 650 muscles attached to the various bones in our body.
• The bones are hard and rigid.
• Cartilages are comparatively soft and elastic.

Functions of skeleton

• Skeleton system gives support to the body.
• It protects the inner organs.
• Together with muscles, it gives the body its shape.
• Red blood cells and some white blood cells are produced in the marrow of the bone.

Muscles:

The bones are moved by the alternate contractions and relaxations of two sets of muscles. Muscle is the tissue of the body which primarily functions as a source of power.

There are three types of muscle in the body :

• Muscle which is responsible for moving extremities and external areas of the body is called “skeletal muscle.”
• Heart muscle is called “cardiac muscle.”
• Muscle that is in the walls of arteries and bowel is called “smooth muscle.”

Cartilage

• Part of the skeleton that is not hard as bones and can be bent, is cartilage.
• They are found in the upper part of the ear, the tip of the nose and at the tips of long bones.

Joints

The area where two bones are attached for the purpose of permitting body parts to move.

• Joints are the points where two parts of the skeleton are fitted together to make movement possible.
• Examples are hip joint, elbow joint, knee joint, etc.

Ball and socket joint:

A joint in which the rounded end of one bone fits into the cavity of the other bones.

Pivotal joint:

A pivotal joint is where our neck joins the head.It joins the neck to the head.In pivotal joint is where a cylindrical bone rotates in a ring. It allows us to bend the head forward and backwards and turn the head to our left or right.

Hinge joint:

Hinge joint is found in the fingers, elbow and knee. It allows movement only in one direction. The knees and elbows have hinge joints.

Fixed joints:

Some of the joints allow no movement. These are called fixed joints.

E.x :  joints in the skull and upper jaw

Ex : 8.2 – “Gaits of Animals”

Muscles and bones help in the movement of animals. The pattern of movement of limbs of animals is called a gait. Gait of lower animals differs from that of larger ones. The pattern of movement of limbs of animals is called as gait. Gait of lower animals differs from that of larger ones.Some animals do not have bones. They have muscles which help to extend and shorten the body. During movement, the animal first extends the front part of the body, keeping the rear position fixed to the ground. After that the animal fixes the front end and releases the rear end. Now the animal shortens the body and pulls the rear end forward. During this practice the animal moves forward by a small distance.

Earthworms :

The body of an earthworm is made up of many rings joined end to end. An earthworm does not have bones. It has muscles that help to extend and shorten the body. During movement, the earthworm first extends the front part of the body, keeping the rear portion fixed to the ground. Then it fixes the front end 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. Repeating such muscle expansions and contractions, the earthworm can move through soil.

Snail :

The rounded structure a snail carries on its back is called the shell and it is the outer skeleton of the snail, but is not made of bones. The shell is a single unit and does not help in moving from place to place. It has to be dragged along. The snail can even hide its head inside the shell.

For movement a thick structure and the head of the snail come out of an opening in the shell. The thick structure is its foot, made of strong muscles. The under surface of the muscular foot is lubricated with mucus, which helps in movement and also reduces the risk of injury from sharp objects. Waves of muscular contractions along this surface help a snail move.

Cockroach :

• The body of a cockroach is covered with a hard outer skeleton that is made of different units joined together.
• It has three pairs of legs for walking and two pairs of wings attached to the breast for flying.
• It has distinct muscles that are used for movement.
• The muscles attached to the legs help in walking.
• The breast muscles attached to the wings help in flying, although they are not good flyers.

Birds :

Birds 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 suited for flying. They are hollow and light, and they don’t have a urinary bladder. These features help them to fly easily.

Snakes :

Snakes have a long backbone and many thin muscles. These are connected to each other even though they are far from one another. The muscles also interconnect the backbone, ribs and skin. It is this interconnected muscles that helps them slither.

Snakes move in S-shaped loops and in a zigzag manner. Each loop of the snake gives it a forward push by pressing against the ground. Since its long body makes many loops and each loop gives it this push, the snake moves forward very fast and not in a straight line.

Fish :

The head and tail of the fish are smaller than the middle portion of the body, and the body tapers at both ends. This body shape is called streamlined. The shape is such that water can flow around it easily and allow the fish to move fast in water.The skeleton of the fish is covered with strong muscles.

Snakes :

• Snakes do not have legs for movement but use their long backbone along with muscles for movement.
• Their body curves into many loops, which gives it a forward push by pressing against the ground.

Conclusion :

• Hinge joint: Hinge joint is found in the fingers, elbow and knee. It allows movement only in one direction.
• Muscle: Muscles are involved in the movement of bones.
• Pelvic bones: Bones in the hip region are called pelvic bones.
• Pivotal joint: The joint where our neck joins the head is a pivotal joint.
• Rib cage: Ribs join the chest bone and the backbone together to form a box. This is called a rib cage.
• Skeleton: The framework of the body which is made up of bones and cartilage is called skeleton.
• Earthworms move by alternate extension and contraction of the body using muscles. Tiny bristles on the underside of the body help in gripping the ground.
• Snails move with the help of a muscular foot.
• The body and legs of cockroaches have hard coverings forming an outer skeleton. The muscles of the breast connected with three pairs of legs and two pairs of wings help the cockroach to walk and fly.
• Strong muscles and light bones work together to help the birds fly. They fly by flapping their wings.
• Fish swim by forming loops alternately on two sides of the body.
• Snakes slither on the ground by looping sideways. A large number of bones and associated muscles push the body forward.

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