Body Movement Class 6 Notes Science Chapter 5

What is Locomotion?

• Locomotion refers to the movement of the whole body from one location to another.
• Locomotion provides a structure that helps shape and support the body.
• The human body is made up of 206 bones.
• Bones serve to protect the internal organs.

Parts of Human Skeleton

• The bones in our body create a framework known as the Skeleton.
• The human skeleton consists of two main parts:
  • Axial skeleton system: This part includes the skull, vertebral column, and the bones of the chest, also known as the rib cage.
  • Appendicular skeleton system: This part consists of the hip girdles, shoulders, and the limbs.

Joints

The point at which two separate bones meet is called a joint. There are four types of joints in the human body.

Ball and Socket Joints

• One end of a bone is rounded and ball-like, and fits into a cup-like depression of the other bone.
• This joint provides movement in any direction.
• Shoulder joints and hip joints are examples.
• In the shoulder joint, the head of the humerus fits into a socket of the shoulder girdle.
• In the hip joint, the large ball-like head of the femur fits into the deep socket of the hip girdle.

Hinge Joints

• The hinge joint functions similarly to a door hinge, allowing movement in only one direction.
• An example of a hinge joint is the elbow joint, which connects the humerus and the ulna.
• Hinge joints can also be found between the bones in your fingers and toes, as well as to a lesser degree in the knee joint.
• These joints are typically strong and provide enough power for movement, while minimizing the risk of twisting at the joint.

Pivotal Joint

• One bone rotates over a pivot-like end of the other bone.
• The skull rotates on the upper end of the back bone.

Fixed Joints

• In this joint, no movement is possible between the two bones.
• The sutures between the bones of the cranium are an example.

Bones and Skeleton

• The skeleton is a framework of all the bones in the human body.
• The skeleton consists of the skull, hand bone, shoulder bone, rib cage, pelvic bone, backbone, leg bone, and cartilage.
• The skull protects the brain.
• The shoulder has the ball and socket joint that helps the arm swing.
• The rib cage protects the lungs, heart, stomach, abdomen, and liver.
• The backbone runs from the top of the skeleton to the bottom of the skeleton.
• It is connected to all the bones.
• The pelvic bone protects the lower abdominal organs such as the urinary bladder, rectum, and uterus.
• Cartilage is a soft bone tissue that connects joints.
• It is present in external parts like the ear and nose.

"Gait of Animals"

Earthworm

• Earthworms move easily on hard and slippery surfaces.
• They have tiny, stiff hair-like projections called bristles under their body.
• These bristles help them grab the soil.
• Earthworms first stretch and then contract their muscles to move.
• As a result, they cover only a small distance with every move.
• A slimy substance secreted by the earthworm helps it to move.
• Earthworms eat their way through the soil.
• They throw away undigested food, which improves the quality of the soil.

Snail

• The outer skeleton of the snail, the shell, is made of calcium carbonate.
• The snail pulls this shell along as it moves.
• The snail can even hide its head inside the shell.
• The strong muscular foot below the shell can protrude.
• The under surface of the muscular foot is lubricated with mucus.
• Waves of muscular contractions along this surface help a snail move.
• The mucus also reduces the risk of injury from sharp objects.
• That is why snails can walk over sharp objects like blades without getting hurt.

Cockroach

• The cockroach has three pairs of legs that help it to walk.
• It has two pairs of wings that help it to fly.
• A cockroach moves its legs with the help of muscles near the limbs.
• It uses its breast muscles to move its wings and fly.
• A cockroach can walk, fly, and even climb.
• A cockroach can move in different terrains like sand and wired meshes.
• This movement is possible because of the spines on its legs.

Birds

• A bird has a body best suited for flying.
• Its wings are actually modified forelimbs.
• Birds can fly easily with the help of these bony forelimbs.
• Birds have light and hollow bones.
• The breast bones hold the muscles of flight that help them to flutter their wings.
• The tail controls the direction of flight.
• Birds have very strong shoulder bones.
• They don't have the urinary bladder, which helps them to fly easily.
• They can walk and perch on trees with the help of their hind limbs.

How do Snakes Move?

• Snakes move in S-shaped loops and in a zigzag manner.
• They cannot move in a straight line.
• They have difficulty moving on very smooth surfaces.
• Snakes have a long backbone and many interconnected muscles that help them to slither.
• They have muscles connecting the backbone, ribs, and skin.
• Snakes can move in grass, sand, and water.
• Snakes do not have arms or legs, but they can climb trees.

Fish

• Fish have a streamlined body, which helps them move fast in water.
• Fish swim with the help of their fins.
• The tail moves from side to side, and helps the fish swim in the right direction.
• Some fish, however, move by bending their bodies from one side to another in quick succession, which produces a thrust that helps it move forward.