2. Introduction to the Human Body
The human body like the bodies of all animals is made up of tissues and
cells and organs,
The study of the human body is called Anatomy,
The systems the human of body can be classified as the immune system,
muscular system, nervous system, skeletal system, digestive system,
respiratory system, urinary system,
The coordination between different systems makes the body function
properly,
If even a single system stops functioning properly it would effect the
entire body.
3. Defining human body
The human body is made up of different organs, they function differently to
carry on all the woks of the body,
The bones give the body its shape and protect vital organs of the body like
the brain, heart and lungs,
Muscles in the body provide us energy. They enable movements to take place
like walking, eating etc.,
The food we eat goes to the stomach where it is converted into energy,
Our blood contains Red blood, White blood cell, Plasma, Platelets,
4. Cells
A cell is the structural and functional
unit of all living organisms,
Our body has millions of these tiny
units,
Our blood, skin and all other body
tissues are formed from different
types of cells,
There are 200 different types of cells
in our body,
A cell is made up of a watery gel called
cytoplasm.
5. Skin & Hair
Skin is the largest organ of the human body ,it covers the whole
body.it protects the vital organs of the body from getting damaged.
When the skin is exposed to sunlight it gets red.dead cells are shed
from the skins surface.
Skin has minute openings in it ,through which hair grows. We have hair
all over our body except for our palms and soles.
Hair is made of keratin.
Hair can be straight wavy or curly and some can be too tiny to be seen
.
6. Muscles
Almost half the body weight is formed by muscles,
Muscles are part of our body that allow us to move. They are made up of
special kind of tissues that can contract and expand,
There are more than 640 muscles, and they hardly ever work alone,
Muscles are arranged in a opposing teams, one team pull the body part one
way, and the other team pulls it back again. As each team pulls, the other
team relaxes and gets stretched.
All the muscles action is controlled by the brain. Which sends and receives
signals through the nervous system.
7. Heart
Heart is a hollow muscular organ in the middle of the chest.
It is fist sized and is made up of cardiac muscles
The heart weighs around 300 gram.
It beats 60 to 80 times in a minute
During exercise the rate of heart beat increases to 200 beats a minute.
Heart is a single organ but acts like a double pump,
Each time it beats it pumps about a cupful of blood.
The heart pumps about 1 million barrels of blood in the average lifetime.
8. Skeleton
The skeleton provides shape to the body and protects the vital organs.
The human skeleton has 206 bones.
Bones are mainly composed of iron calcium , phosphorous and fibrous
substances known as collagen.
There 230 movable and semi movable joints in our body.
The largest bone is pelvis or the hip bone.
The smallest bone of the body is the stirrup , deep in the ear it is as small as
a grain of rice.
The longest bone is the femur in the thigh .
9. Blood Circulation
There is a continuous flow of blood in the body this is known as blood
circulation.
Blood circulation consists of the heart and the blood vessels
De-oxygenated blood is pumped to the heart. And the heart pumps back
oxygen rich blood back to the body.
Blood consists of platelets, red and white blood cells .
Blood protects the body from illness.
In fetal circulation, the lungs are inactive. A flap valve allows mixing of
blood in left ventricular chamber , but this valve soon closes after first
breath is taken
10. More on Blood Circulation
Within a tiny drop of blood there are 5 million blood cells.
About 8 million blood cells die in your body every second and about the
same no. are produced
It takes 20 secs for a red blood to circulate the whole body
Red blood cells may live for about four months, circulating in the body and
feeding 60 trillion other cells
11. Nervous and Respiratory System
The nervous system consists of nerves that carry information from the
senses to the brain.
These nerve are made up of cells called neurons.
The air is inhaled by us via the trachea into the lungs. The air we inhale
passes through the wind pipe into the lungs.
When we breath out ,the lungs push used air out through the nose and
mouth.
Unlike other body cells brain cells cannot regenerate.
If we opened up all the vains of the human lungs it would make a length of
two times the width of the earth.
12. Digestive System
The process-from the moment the food
enters the mouth until it enters the blood
stream-digestion
Digestive system consists of organs which
help in chewing , swallowing, breakdown,
absorption and expulsion from the body of
unused waste matter.
Gastric juice, pancreatic juice and bile
helps in converting food into a fine paste.
Within 2-6 hours all food is emptied into
the small intestine
Around 1.7 lit of saliva is produced each
day.
13. Excretory system
The urogenital system is related to kidneys which
maintain the volume and composition of body fluid
Kidneys help in maintaining the body's internal
environment.
Kidney filters about 180 quarts of blood everyday.
When resting, about half the energy used by the
muscle, liver and kidneys is derived from fat
Our nose is a personal air conditioner ,it warms
cold air and heats cold air and filters impurities
The senses of the taste and smell are connected.
14. Senses for Smell
,Taste,Light,Sound and Touch.
we can distinguish 4000 different smells,
our nose is used to differentiate between good and bad
odours. the tongue receptors can differentiate four
types of taste
The tongue can differentiate four types of taste sweet,
salty, bitter and salty
The eye does not actually see objects, instead it sees
the light they reflect.
Any sound , music and words is simply a vibration.
