Introduction to Body movements
The ability of organisms to change position, by using their body parts, is called movement.
- Skeleton is the internal structure in organisms which helps in bringing about movement.
- It forms a framework that gives the shape of the body and provides support to organisms.
- The skeleton is made up of bones.
- Different kinds of bones are joined to each other in a particular manner.
- These joints facilitate various types of movements.
- In higher animals, bones, muscles and cartilage together make the movement possible.
- Muscles are parts of the body which help in bringing about movement.
- Muscles may be attached to bones, (humans) or may work alone (earthworm).
- 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 are the points where two parts of the skeleton are fitted together and make movement possible.
- Examples are hip joint, elbow joint, knee joint, etc
Ball and Socket Joint
- Ball and socket joint, where the rounded end of one bone fits into the cavity of the other bone.
- It brings in movement in all directions.
- It is seen in the hips and shoulders of the human body.
- A pivotal joint is where a cylindrical bone rotates in a ring.
- It joins the neck to the head.
- It allows to bend the head forward and backwards and turn the head to our left or right.
- Hinge joints bring about movement in only back and forth direction.
- The knees and elbows have hinge joints.
- The following image is a hinge joint in the elbow.
- Fixed joints are immovable joints because the bones are joined together.
- Such joints are found in the skull.
Gaits of Animals
The different patterns of movement of animals due to the differences in their skeletal structure are called gaits of animals.
- The earthworm does not have any internal skeleton.
- The body is made up of many rings joined end to end and muscles attached to these rings help to extend and shorten the body.
- The skin of earthworm also has a large number of tiny bristles that help it get a good grip on the ground.
- Repeated extension and contraction of the body muscles, enable the earthworm to move through the soil.
- Snails move with the help of their muscular, flat foot.
- They glide along a solid surface which is lubricated with mucus.
- This motion is powered by succeeding waves of muscular contractions of the foot.
- 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 have a special skeletal and muscular structures that help them to fly.
- The forelimbs are modified to become wings and the bones inside are hollow to suit flying.
- The bones of the hind limbs are used for perching and walking.
- The shoulder bones and breastbones are strong and support muscles of flight which move the wings up and down.
- Fishes have a streamlined body that helps them swim with least resistance.
- They use tail fin for small jerks through water and other fins assist swimming.
- The tail fin is also used for changing directions.
- 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.
Learn more about the Body movements, Bones, joints, and about the skeletal system from the topics given below: