Syllabus Study Notes

Class VI >> Science >> Body movements >> Free Detailed Study Notes

IMPORTANT TERMS

Joints                         Place where two bones meet.

Skeleton                      A framework of hard and strong bones.

Vertebrae                     Small bones that make up the backbone.

Cartilage                      A tough, elastic tissue covering the end of the bones.

Streamlined                 Shape that is narrow in front and broader in the middle.

 

MOVEMENT IN ANIMALS

Each animal has a distinct way of moving. The body structure of an animal determines the kind of movement they show. Animals are divided into two groups based on the presence or absence of the backbone. 

  • Vertebrates - Animals that have a backbone are called vertebrates. E.g. Horse, frog, bird, etc.
  • Invertebrates - Animals that do not have a backbone are known as invertebrates. E.g. Snail, earthworm, cockroach, etc.

 

MOVEMENT IN EARTHWORM

  • An earthworm is an invertebrate.
  • An earthworm's body is made of segments. These segments have tiny, hair-like bristles, which help it to grip the surface and pull its body forward.
  • The shape of an earthworm's body is like a long tube. Its body shape is maintained by the fluid present in its body. It has a liquid skeleton.
  • An earthworm’s body secretes a slimy substance which helps in the movement.

 

MOVEMENT IN SNAIL

  • A snail is an invertebrate.
  • Snails have a shell that they use to hide from enemies and protect them from the heat of the sun. This shell is the outer skeleton but it is not made of bones. It is a liquid skeleton.
  • The foot of a snail is made of strong muscles, which produces a slimy substance called mucous. The snail crawls on the layers of mucous. 

MOVEMENT IN COCKROACH

  • A cockroach is an invertebrate.
  • A cockroach's body is covered with a hard outer skeleton. It has two pairs of wings and a pair of antennae.
  • Cockroaches have three pairs of legs and they move three legs at a time while moving.

MOVEMENT IN SNAKE

  • Snakes are vertebrates as they have flexible backbones.
  • A snake curves its body into many loops. Each loop gives it a forward push by pressing against the ground. The snakes move very fast in a wave-like manner.
  • Snakes crawl on their bellies; they have scales and a flexible backbone which help them in crawling.

MOVEMENT IN BIRDS

  • Birds are vertebrates.
  • Birds have streamlined bodies, which help them to move through air.
  • Birds have hollow bones which make them lightweight. The hollow bones make it easier for the birds to fly.
  • They have strong muscles which help them to flap their wings and fly.

 

MOVEMENT IN FISH

  • Fishes are vertebrates.
  • Fishes have streamlined bodies, which help them to swim through water.
  • Fish swims with the help of fins and the backbone.
  • Most fishes have swim bladder that can be filled with air or emptied to help them, while moving in water.

 

MOVEMENT IN HUMAN BEINGS

Human beings are vertebrates. The human body is supported by a framework of bones called skeleton. The muscular system along with skeleton system is responsible for the movement of the human body. There are 206 bones in the human skeleton. It performs the following functions:

  • The skeleton provides shape and support to the body and helps in movement.
  • The skeleton provides a framework and holds the human body upright.
  • A human body has many soft organs. The skeleton system provides a hard framework to support these organs such as heart, brain etc.

 

JOINTS IN THE HUMAN BODY

There are three main types of joints in the human skeleton:

  • Fixed joints do not allow any kind of movement. The joints in the skull are examples of fixed joints.
  • Slightly movable joints allow very little movements. E.g. The joints between most vertebrae.
  • Freely movable joints allow a variety of movements. E.g. Elbow and knee joints.

 

Types of Movable joints:

  • Gliding Joint- This kind of joint allows bones to glide over each other and provide very little movement in all directions. The ankle and the wrist have gliding joints.
  • Ball-and-socket joint – In this joint, the ball-like structure of one bone fits into the hollow space of the other bone. E.g. Joint of upper arm and shoulder
  • Pivot Joint – In such joints, the rounded surface of one bone fits into a ring formed by the other bone, in a way that one bone is able to rotate over the other. E.g. joint where the neck joins the head.
  • Hinge Joint – This joint allows only back and forth movement. Joints at the knee and elbow are the examples of hinge joint.

 

PARTS OF THE HUMAN SKELETON

  • Skull – The bony part of the head is known as skull. It is a structure of 22 bones that surrounds and protects the brain.
  • Backbone – Backbone or spine is made up of 33 small bones called vertebrae that protect the delicate spinal cord.
  • Rib cage – The ribs join the chest bone and the backbone together to form a cage. This rib cage protects the heart and the lungs. There are 12 pairs of ribs in a human body.
  • Limbs -   The human body has two pairs of limbs: the forelimbs (or arms) to carry or manipulate objects and the hind limbs (or legs) for locomotion.

 

X-Rays

  • Wilhelm Conrad Roentgen, a German physicist discovered X-rays in 1895.
  • X-rays are used to find out about any possible injuries that might have happened to the bones.

 

INTERESTING FACTS

  • Penguin is the only bird that cannot fly but can swim.
  • Tongue is a group of muscles which helps in chewing.
  • Fish like shark and ray have no bones. Their skeleton is made of cartilage.
  • Ostrich is the largest bird in the world. It cannot fly.
  • The longest bone in the human body is the thigh bone called the femur.