Central Nervous System:

Central Nervous System:

The Brain along with spinal cord constitutes the nervous system .

The brain consist of

1.Cerebrum : The largest part of the brain consisting of two hemispheres which controls voluntary actions and are the seats of intelligence, memory, imagination and will.

2.Cerebellum : The large mass having ridges and furrows attached to cerebrum, which regulates muscular movement of locomotion.

3.Medula Oblongata : The lowermost part of the brain which continues as  the spiral cord in vertebral column. It control involuntary action.

Glands of Human body

Glands of Human body :

Organs of the human body which manufactures aome liquid products which are secreted from the cell are called glands.

Ducted Glands : also know s Exocrine glands secrete their product through well defined ducts e.g  Liver- Production of bile, Lachrymal- secretes tears in the eyes;Salivary – Secretes saliva in the mouth;Sweat gland secrete sweat.

Ductless Glands : Also know as Endocrine glands or internally secreting glands. They secrete hormones directly in the blood stream in response to instructions from the brain

Main Organs of Human Body

Main Organs:

Heart: The heart is situated in the centre of the thorax ,just behind the breast the breast bone-sternum and is enclosed in a tough membrane called the pericardium. Its average weight is about 340 grams in men and 225 grams in women. Contraction and relaxation mechanism of ventricles results  a heart beat of 70-72/min in males and 78-82/ min in females. Contraction of ventricles is called systole and relaxation is called diastole. Circulation of blood in the body is regulated by heart.

Lungs :  A pair of spongy organs consisting of elastic tissues situated in the chest cavity. There are two lungs, the right lung is larger than the left lung. Together they weight upto 1.18 and 1.19 kg in a health adult. Their main function is to purify blood and supply Oxygen to it. The entire blood supply (4.5 to 5 litres) washes through the lungs about once a minute.

Liver : The Liver situated on the right side of the stomach is the largest gland in the human body. It weights around  8812 grams. The gall bladder is attached to the liver and stores bile produced by it. The liver is responsible for the metabolism of the products of digestion, storage and release of substances (principally glucose) so as to maintain constant level in the blood.

Kidneys: The two kidneys are situated in the upper posterior of the abdominal cavity, one on each side of vertebral column. Each kidney is approximately 10 cm long, 5 cm wide and 2.5 cm thick. They filter nitrogenous waste of the body from the blood and throw it out in the form of urine.

Human Brain : Consist of two parts : The brain located in the skull and the spinal cord located in the vertebral column.

The weight of average human brain triples between birth and adulthood. The final weight of a brain in an adult male is about 1.4 kg and 1.3 kg in case of woman) which averages about 3 % of body weight.

The Human brain uses about 20 % of the oxygen a man breathes, 20 % of calories a man takes in and 15 % of body blood.

Musclar System in Human Body

Musclar System :

Muscles are tissues attached to bones and composed of fibres. They are capable of contracting and relaxing to effect body movements.

Total Number of Muscles : There about 630 important muscles in human body, which normally account for 40 per cent of the body weight.

Largest Muscle : The bulkiest muscle in the body is gluteus maximus or the buttock muscle.

Longest Muscle : Sartorius is the longest muscle in the body which originates in the upper part of the hip bone and is attached to tibia bone of the leg.

Smallest Muscle : Stapedius muscle in the middle ear.

The Sketetal System: - Human Bones

The Skeletal System:

There are around 206 bones in the skeletal system of an adult. Bones of hands and feets only constitute 50 % of the total bones in the human body.

A new born baby has 300 bones, out of which 94 bones fuse together as it grows.

The Largest bones in the human body is the femur in the thigh. The average length of this bone is 50 cm.

The shortest bone in Human body is the Stirrup bone in middle ear.

Composition of Bones	Percentage
Organic Matter	33.30%
Phosphate of Lime	51.04%
Carbonate of Lime	11.30%
Flouride of Calcium	2.00%
Phosphate of Magnesia	1.16%
Soda/Chloride of Sodium	1.00%

Blood Grouping- A, B, AB and O

Blood Grouping :

K.Landsteiner in 1900-1902, classified human blood into four groups, A,B, AB and O. The O Group blood can be given to any other groups and therefore a person possessing the O group is known as a universal donor. Group AB is called universal recipient and can receive from A,B,AB and O blood Groups

Column1	Column2	Column3
Blood Group	Can donate blood to	Can receive blood from
A	A,AB	A and O
B	B,AB	B and O
AB	Only AB	AB, A, B and C
O	AB, A ,B and O	Only O

Groups Blood Clotting  : Blood Clotting is a body defence system to combat bleeding. Plasma contains fibrinogen-a soluble ‘protein’ which produces insoluble protein called fibrin essential for blood Clotting which is produced in liver.

Blood and Constituents of Blood

Blood contained in blood vessels is a connective tissue in form of a red viscous fluid. On an average, a healthy man has about 5 litres of blood in his body, while a women has about 500 ml less than a man. Total volume of blood is said to be around 60-80ml per kg of body weight.

Constituents of Blood :

There are two main constituents of blood : solid or cellular part called blood cells (35 %) and the fluid called as plasma (65 per cent).

The blood cell are further divided in two parts.

1)      Red Blood Corpuscles  (RBC) : These are disc-shaped cells without nucleus and contains pigment called Haemoglobin which gives the red color of the blood. Haemoglobin is a iron containing pigment .  RBC are produced in the spleen and the bone marrow. Haemoglobin  picks up oxygen in the lungs by forming a chemical compound.

2)      White Blood Corpuscles (WBC) : These are round semi-transparent cells containing a nucleus and are little larger in size than RBC. The WBC are the soldiers of the body’s defence systemand their main function is to combat infection
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