Download Chapter 9 THE BODY AND ITS MOVEMENT

Chapter 9
THE BODY AND ITS MOVEMENT
1) All living things are made up of cells.
2) Cells make up tissues ; tissues make up organs ; organs make up organ system ; organ
systems make up the human body
3) The main organ systems in the human body are skeletal , muscular , circulatory ,
nervous , respiratory , digestive , excretory and reproductive.
4) The skeleton gives support and protection , helps in the movements and makes blood
cells.
5) The human skeleton can be divided into four main parts – skull , backbone , ribs and
limbs.
Functions of the skeleton
The skeleton has four main functions :
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Support – skeleton provides framework and holds us upright .
Protection – the bones protect the soft organs of our body . The brain is protected by
the skull ; the heart and the lungs by the thin long bones in your chest called the ribs .
c) Movement – though the individual bones are hard , several of them move at places
where they are joined to other bones.
d) Making blood cells – bones are hard from outside but they are soft and spongy in the
inside. The inside of bones contains a soft substance called the bone marrow. Blood
cells are made in the bone marrow .
Structure of the human skeleton
a) The skull –
The skull is the bony structure that surrounds and protects the brain . The upper part is
made up of 8 flat bones joined together . The face and jaw contains 14 bones . The
lower jaw bones is the only movable bone in the skull .
b) The backbone or spine –
The backbone consists of 33 small bones called the vertebrae . The vertebrae are joined
to each other . The joints allow slight movement if the vertebrae . This is why you can
bend and twist your back . The backbone is attached to the base of the skull . It forms
the central supporting rod for the skeleton . Each vertebrae has a hole in it. The delicate
organ of your body called the spinal cord passes through these holes . Thus , the
backbone the spinal cord .
c) The rib cage –
The ribs are thin , flat , curved bones that form a protective cage around the organs in
the upper part of the body . This is called the rib cage . The rib cage consists of 24 bones
arranged in 12 pairs . All of them are joined to the backbone at the back . Most of them
are joined to the breast bone at the back . The last two pairs that are not joined to the
breast bone are called floating ribs. The rib cage protects the heart and the lungs .
c) The limbs { arms and legs } –
The longest bone of your body is the thigh bone or the femur . The ankles and the feet
have a number of small bones . The upper arm has one long bone called the humerus .
JOINTS
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Hinge joint –
The elbow , knee and finger joints allow movement in one plane only , that is , up and
down , or backward and forward , like the hinges of a door . Such joints are therefore
called hinge joints .
b) Ball and socket joint –
The shoulder and hip joints allow movements in all directions . In such joints , the end
of one of the bones is round as a ball . It fits into a hollow part (or socket ) in the other
bone .
c) Pivot joint –
The neck joint also allows movement in all directions . It allows you to move your head
up and down , left and right and also to rotate it. In such joints , one of the bones ends
in a rounded or conical surface that fits into a dent in the other bone . Such a joint is
called a pivot joint .
d)Gliding joint –
The wrist or ankle joints have flattened ends of bones that can move (or glide) against
each other . These joints allow side – to – side as well as backward and forward
movement .
MOVEMENTS
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earthworms have liquid skeletons . To move , the earthworm first extends the
front part of its body , keeping the rear part fixed to the ground . Next , it fixes
the front part and shortens it , thus pulling the rear end forward . It carries out
such expansion and contraction of muscles repeatedly to move forward .
2) Skeleton which is outside the body is known as an exoskeleton . Crabs and insects
such as cockroaches also have exoskeleton . The snail has a thick structure called a foot .
It is made up of strong muscles . It produces a series of wave like movements that push
the snails body forward .
3) The skeleton of a human body is inside the body.
Such an skeleton is known as endoskeleton . Fish , amphibians , reptiles , birds and
mammals have endoskeletons . Muscles that enables the fish to move are found on
either side of the backbone . These muscles contract on one side and expand on the
other .
TOPIC –THE HABITAT OF THE LIVING
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HABITAT- The natural surrounding where a living organism lives is called its
habitat .
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TYPES OF HABITATS
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TERRESTRIAL HABITAT – it consist of habitats on land like forests ,desert
,grassland and mountain .
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AQUATIC HABITAT – it includes habitat in water like ponds , lakes ,river and
oceans .
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ARBOREAL HABITAT – it includes habitat on trees .
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AERIAL HABITAT –it includes sky or air for activities .
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AMPHIBIOUS HABITAT - it includes habitat both on land and water .
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COMPONENTS OF A HABITAT
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LIVING COMPONENT ,also called BIOTIC COMPONENT .
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NON LIVING COMPONENT ,also called ABIOTIC COMPONENT .
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BIOTIC COMPONENT include plants and animals .ABIOTIC COMPONENT
includes soil ,rocks ,air ,water ,light and temperature .
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ADAPTATION - The presence of features or certain habits which help an
organism to live in a particular habitat or environment is called adaptation .
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ADAPTATION IN A CAMEL
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A camel has long legs which help to keep the upper part of the body away
from the heat of the sand .
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After drinking water once ,it can live without water for many days .
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A camel excretes as small amount of urine and its dung is dry
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A camel does not sweat .
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Its feet have thick pads .
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A camel has long eyelashes which do not allow flying sand to reach its eyes
in a sand storm .
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A camel can close its nostrils .
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Fat stored in its hump acts as a food reserve.
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ADAPTATION IN A LION (PREDATOR)
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Eyes face forward , which help in locating the prey.
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Long and sharp canines help in tearing the flesh.
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The skin is light brown in colour or patchy so as to hide in the dry grass while
hunting for prey.
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They have sharp claws to catch , hold and tear the body of prey.
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Adaptation in deer
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They have strong teeth for chewing and cutting hard grass .
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Their ears are long to detect the movement of predators .
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They have long legs to run fast and escape predators.
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They have eyes on the sides of their head which help to look in all the directions
for predator’s presence.
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Adaptations in fish
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Their body shape is streamlined and fins are present these features help them in
swimming.
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Their gills are present , which help the fish to breathe under water .
MOTION AND MEASUREMENT
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Ancient unit of measurement
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HANDSPAN – It is the length between the tip of the thumb and the little finger
when stretched .
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CUBIT –IT is the length between the tip of the middle finger and the elbow.
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ARM LENGTH –It is the length between the shoulder and the middle finger
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FOOT STEP- It is the length between thumb and the heal of the foot .
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These unit lack precision because hand , arm, and foot length of all human is
not the same .
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For the sake of uniformity standard system of unit is accepted all over the world
and is known as INTERNATIONAL SYSTEM OF UNITS or S.I. units .
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S.I UNIT of length is metre .
MOTION AND TYPES OF MOTION
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A body is said to be in motion if it changes its position with respect to time
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LINEAR MOTION – An object is said to be in Linear motion if it moves from one
position to another along a straight line in one direction only.
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For eg an apple falling from a tree
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CURVILINEAR OR RANDOM MOTION - An object is said to be in random motion
if it changes its direction in an irregular manner .for eg a butterfly flying in a
garden .
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CIRCULAR MOTION – an object is said to be in circular motion when it moves on
its own axis or around a fixed centre .for eg movement of a spinning top .
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OSCILLATORY MOTION – The to and fro motion of an object about its position of
rest is called oscillatory motion .for eg a pendulum.
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Vibratory motion is actually very fast to and fro motion .for eg strings of guitar
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PERIODIC AND NON PERIODIC MOTION - The motion where an object repeats
its motion after a fixed interval is called periodic motion .for eg the movement of
hands of a clock .
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NON PERIODIC motion is that is not repeated at regular interval of time . For eg
the beating of heart .