Excretory system
Kidneys, uriniferous tubules, urinary bladder, lungs and skin create this excretory system.
The main work of this system is to throw waste materials out of body. The body works regularly and produces a lot of waste materials which get mixed in the blood. The kidneys remove these waste materials from the blood and make urine and send it to urinary bladder. This urine is thrown out of the body from time to time through ureters.
Some excretory materials are also coming out from other organs of the body as –carbon dioxide from lungs, sweat from shin, excreta and foul air from rectum and anus.
Excretion of different waste materials is very necessary t keep the body healthy.
Nervous system
Brain, spinal cord and nerves make nervous system. There is a net of nerves in the whole body. Nervous system works under control of the brain. Several nerves are also connected to the spinal cord.
Our brain gets information by help of nerves related with sense organs and other body parts. It orders these organs through these nerves to work. We get power to learn, to understand and to think from our brain.
Endocrine system
There are some special glands in our body, which are called endocrine glands. These glands open direct in the blood, so they are also called ductless glands. From these glands hormones are secrete. These glands make endocrine system. Pituitary gland, thyroid gland and adrenal gland are some special endocrine glands.
Reproductive system
Human beings produce progeny like themselves. Male and female have different reproductive organs. Male has one pair of testis and other reproductive organs. In the same way female has one pair of ovary and other reproductive organs.
Only female gives birth to off –springs
In human body there are different organs and other organ systems. They all work jointly. In reality by the joint working of this system, the human body machine works.