CBSE Class 6 Science Revision Notes Chapter 8

CBSE Class 6 Science Revision Notes Chapter 8 – Body Movements

The human body system is made up of numerous components. Each is in charge of performing specific bodily functions. An organ is a set of tissues within a living thing that has been modified to serve a particular purpose. The skeletal system refers to the internal framework of a body, which is composed of bones and cartilage. It allows us to move with greater ease and stability. The skeletal system is divided into various components, including the backbone, skull, shoulder and pelvic bones and cartilage.

CBSE Class 6 Science: Chapter 8: Body Movements covers the fundamental and important concepts of biology, laying the groundwork for higher classes.A simple and comprehensive guide is necessary for students to understand the topic well and score better on exams. Extramarks offers Revision Notes for Class 6 students prepared by subject matter experts. These notes are written in an easy-to-understand language and explain concepts with diagrammatic representations for a better grasp of the subject. Extramarks’ Revision Notes are available on the website so that students can access them easily. 

Revision Notes for CBSE Class 6 Science Chapter 8 

Access Class 6 Science Chapter 8 – Body Movements Notes

Terminologies:

The term locomotion refers to a variety of body movements, such as running, walking, jumping, crawling, swimming, etc., that result in a change in the body’s posture. It also refers to the movement of an organism from one location to another.

An organism’s skeletal and muscular systems allow for movement and locomotion.

Skeletal System

The skeletal system, also known as the skeleton, is made up of various bones that are joined to one another helps in movement and provides the body its structure. 

Bones are of different sizes and shapes. X-rays beams are used to produce images of internal organs, particularly bones. Hence, they are helpful when the bones in certain regions are fractured.

Humans have 305 bones when they are born, but as they grow, some of those bones join together, reducing the number to 206.

The carpals are eight tiny bones that make up the wrist.

The delicate internal organs like the heart, lungs, and brain are protected by the skeletal system.

For example, the rib cage and chest bones, also known as the ribs, protect the heart and lungs. The human rib cage is made of twelve pairs of ribs, which is connected to the sternum in the front and the vertebral column in the back. The lungs and heart are housed inside a box-like structure that is formed when they are bent to join the backbone at the back.

Below the stomach, pelvic bones support the sitting of the stomach and aid in thigh movement.

Joints

A joint is a connection that takes place between bones in the skeletal system. It is also referred to as an articulation or an articular surface. Motion is made possible by joints. The degree and nature of mobility in a particular joint are determined by its type and features.

Types of Joints

Joints with a ball and socket: In a ball and socket joint, one bone has a hemispherical head while the other bone has a cuplike depression. The rounded end of one bone fits into the cavity of the other bone to form a joint. Bones can move freely at these joints in all directions. For example, the joint where the hip and thigh bones meet is a ball and socket joint.

Pivotal Joints – In pivotal joint, a cylindrical bone rotates in a ring. An example of 

Hinge Joints: Bones can only move very little in these joints. A hinge joint is a joint between two bones that enables movement in only one direction. For example, the elbows contain the hinge joint.

Fixed Joints: Joints that cannot move or bend are referred to as fixed joints. For example, the skull is a fixed joint.

Muscular System

Muscles are part of the body that help with movement by contraction and relaxation. They help the head, arms, legs, and other body parts to move.

Muscles work in pairs. When one of them contracts, the bone is pulled in that direction. The other muscle in the pair relaxes. To move the bone in the opposite direction, while the contracted muscle relaxes, while the relaxed muscle contracts to pull the bone back to its original position.

A muscle can only contract. It is unable to push. To move a bone, two muscles must work together.

Locomotion in Animals

Earthworm: Bristles, which resemble tiny hairs, are a feature of earthworms that enable them to anchor a portion of their bodies to the ground. While keeping its back anchored to the ground, the earthworm first expands the front portion of its body. The front end is then fixed, and the back end is released. The body is then pulled forward and made shorter.  This causes it to move forward slightly.Because they lack bones, earthworms can contract and relax to move.

Snail: An opening in the shell allows a thick structure and the snail’s head to emerge. The thick structure is its foot, which is formed of strong muscles. Snails use their musculotendinous foot to propel them forward.

Cockroach: A cockroach uses three pairs of legs for locomotion. A hard outer skeleton that covers their bodies is made up of various plates and aids in movement. The cockroaches’ wings enable them to fly.

Bird: Birds can walk on the ground and fly through the air because their bodies are well suited for these activities. Their forelimbs have hollow bones and are modified into wings for flight. Walking and perching typically require the bones of the hind limbs. The shoulder bones are strong to help in flight. Also, the breast bones are altered to hold the flight muscles that are needed to raise and lower the wings.

Fish: Fish have streamlined bodies, fins, and tails. Their body muscles also bend and form curves to aid in swimming.

Snakes: Snakes have long spines along with many delicate muscles. The skin, ribs, and backbone are all joined together by muscles. Their muscles and backbones exhibit a slithering movement.

The snake’s body performs several loops to move. By pressing on the ground, each loop of the snake propels it forward. The snake moves remarkably fast, but not in a straight line because of the numerous loops its lengthy body performs, each of which provides it with a push.