Body Movements

Human Body and Its Movements

Let’s explore how our bodies move! Sit still and observe your body’s movements. Notice your blinking and breathing. These are some of the many movements our bodies make.

Moving Parts of Our Body

• When writing or turning to look at a friend, different body parts move.
• We also move from place to place by walking, running, skipping, jumping, etc.

How Animals Move

Animals move in various ways:

• Walking, running, flying, jumping, creeping, crawling, slithering, and swimming.

Human Body and Its Movements

Let’s start with our movements:

• Physical exercises involve moving hands and legs differently.
• Try bowling an imaginary ball, rotating your arm at the shoulder, or bending your arm at the elbow and leg at the knee.

Why Do Some Parts Move Easily?

• We can move some body parts in various directions and others in just one.
• Some parts, like the elbow, can’t move if a scale is tied to them.

Joints in Our Body

• We can bend or rotate where two parts join, like the elbow, shoulder, or neck.
• These places are called joints.

Bones and Joints

• Press different parts of your body to feel the hard structures called bones.
• Bones can’t bend, so they join at points like the elbow for movement.

Types of Joints

1. Ball and Socket Joints

• Roll a paper into a cylinder and insert it into a ball. The ball in a bowl rotates like your shoulder joint.
• This joint allows movement in all directions, like your hip joint.

2. Pivotal Joint

• The neck joint, where the neck joins the head, is a pivotal joint.
• It allows the head to bend forward, backward, and turn left or right.
• This movement is different from the arm’s circular rotation in a ball and socket joint.

Activities to Try

3. Hinge Joints

• Example: A door’s movement.
• Movement: Hinge joints, like in the elbow, allow back-and-forth movement only.

4. Fixed Joints

• Example: Joints in the head.
• Function: Fixed joints don’t move, like the joint between the upper jaw and the rest of the head.

The Skeleton

• Function: Bones form a framework called the skeleton, giving shape to our body.
• X-rays: Used by doctors to see bones and check for injuries.

Exploring Bones

• Feel Bones: In your forearm, upper arm, lower leg, and upper leg.
• Finger Joints: Bend them and count how many bones are in the middle finger.
• Wrist Bones: Called carples, making the wrist flexible.

Interesting Facts

• Number of Bones: 305 bones at birth, reducing to 206 in adulthood as some bones fuse.

Rib Cage

• Function: The rib cage protects important internal organs.
• Structure: 12 ribs on each side, forming a protective box.

Backbone

• Structure: Made of 33 small bones called vertebrae.
• Function: Allows bending and protects the spine.

Shoulder and Pelvic Bones

• Pelvic Bones: Form the part you sit on and support the lower body.

Skull

• Structure: Made of many joined bones.
• Function: Protects the brain.

Cartilage

• Definition: Cartilage is a part of the skeleton that is not as hard as bones and can be bent.
• Example: Feel your ear – the upper part is cartilage, not as soft as the ear lobe but not as hard as a bone.
• Location: Found in joints and other parts of the body.

Skeleton Structure

• Components: Made up of bones, joints, and cartilage.

Muscles and Movement

• Muscle Contraction: Make a fist, bend your arm, and touch your shoulder. Notice the muscle bulging in your upper arm. This is due to muscle contraction.
• Muscle Function: When muscles contract, they become shorter, stiffer, and thicker, pulling the bone.
• Muscle Pairs: Muscles work in pairs. One muscle contracts to pull the bone while the other relaxes. To move the bone back, the opposite muscle contracts.

Key Points

• Muscles Pull, Not Push: Muscles can only pull bones, so they work in pairs to move bones in different directions.

Movement in Other Animals

• Question: Do all animals have bones?
• Examples: Earthworms and snails move differently since they don’t have bones.

Summary

• Cartilage is flexible and found in various parts of the body.
• The skeleton consists of bones, joints, and cartilage.
• Muscles work in pairs to move bones by contracting and pulling.
• Different animals have different ways of moving, not all involving bones.

Conclusion

Our bodies have different types of bones , joints and muscles to help us move in various ways. Understanding these can help us appreciate how our bodies function and how animals move differently.

Gait of Animals

Let’s explore how different animals move!

a. Earthworm

• Body Structure: Made of many rings, no bones.
• Movement: Uses muscles to extend and shorten its body.
  • Extends the front part while the rear is fixed, then pulls the rear forward.
  • Secretes a slimy substance to help move.
• Grip: Tiny bristles under its body help it grip the ground.
• Function: Eats soil and helps make it useful for plants.

b. Snail

• Shell: A rounded outer skeleton, not made of bones.
• Movement: Uses a muscular foot that moves in a wavy motion.
• Speed: Moves slower than an earthworm.

c. Cockroach

• Movement: Walks, climbs, and flies.
  • Has three pairs of legs for walking.
  • Two pairs of wings for flying.
• Body Structure: Hard outer skeleton made of plates.
• Muscles: Different muscles for moving legs and wings.

d. Birds

• Movement: Fly in the air, walk on the ground, some swim.
• Body Adaptations:
  • Hollow and light bones for flying.
  • Hind limbs for walking and perching.
  • Forelimbs modified as wings.
  • Strong shoulder bones and breastbones to support flight muscles.

e. Fish

• Streamlined Shape:
  • Fish have a streamlined body with the head and tail smaller than the middle.
  • This shape helps water flow around easily, aiding movement.
• Movement:
  • Fish use strong muscles to curve their body from side to side.
  • The tail swings in the opposite direction, creating a series of jerks that push the fish forward.
  • Fins help in balance and direction.
• Example: Divers use fin-like flippers to move easily in water.

f. Snakes

• Movement:
  • Snakes slither and do not move in a straight line.
  • They have a long backbone and many thin muscles connected to each other.
  • The body curves into loops, and each loop pushes against the ground, moving the snake forward.

Understanding Animal Movement

• Questions to Explore:
  • Why do animals have different body parts for movement?
  • What are the similarities and differences in these body parts among different animals?
  • Why do some animals have an even number of legs?
  • Why do our legs bend differently from our arms?

Interesting Fact: Yoga for Better Health

• Benefits of Yoga:
  • Keeps the backbone erect and prevents slouching.
  • Strengthens bones and prevents osteoporosis.
  • Relieves joint pain, especially in the elderly.
  • Tunes muscles and keeps them active.
  • Keeps the heart healthy and efficient.
  • Note: Certain yoga postures should be performed under supervision.

Understanding how different animals move helps us learn more about their body structures and adaptations!

Chapter Summary:

• Bones and cartilage form the skeleton of the human body.
• The skeleton gives the body its frame and shape.
• It helps in movement and protects inner organs.
• The human skeleton includes:
  • Skull
  • Back bone
  • Ribs and breast bone
  • Shoulder and hipbones
  • Bones of hands and legs
• Bones move by alternate contractions and relaxations of two sets of muscles.
• Bone joints vary depending on their type and the direction of movement they allow.
• Birds have strong muscles and light bones to help them fly by flapping their wings.
• Fish swim by forming loops on two sides of their body.
• Snakes slither by looping sideways, using many bones and muscles to push their body forward.
• Cockroaches have hard coverings forming an outer skeleton.
  • They have three pairs of legs and two pairs of wings connected to muscles in the breast.
  • These muscles help cockroaches walk and fly.
• Earthworms move by extending and contracting their body using muscles.
  • Tiny bristles on the underside help grip the ground.
• Snails move with the help of a muscular foot.

Keywords

Serial No.	Keyword	Serial No.	Keyword
1	Backbone	10	Muscle
2	Ball and socket joint	11	Outer skeleton
3	Bristles	12	Pelvic bones
4	Cartilage	13	Pivotal joint
5	Cavity	14	Rib cage
6	Fixed joint	15	Shoulder bones
7	Gait of animals	16	Skeleton
8	Hinge joint	17	Streamlined
9	Muscle