We use different types of devices to meet our various needs of everyday life such as-automobiles. refrigerator, television, steam engine, internal combustion engine etc. Many people designated human body as a machine. Though human body is not a machine at all, it behaves as a machine in many aspects. As like as a machine, it is also made up of many small parts or organs, absence or infumity of one organ the activities of the whole body is disturbed. Each part of the body, like each part of a machine, does special jobs.
Each organ of human body is interconnected with other organs, each organ runs at its own individual speed, but all function in a specific way and there is a predetermined relationship to each other. In this sense, the human body is analogous to the most complicated man-made machines.
Heart, kidneys, lungs, liver etc. are such parts of human body. As for example- heart is actually an automatic pump, which is able to circulate blood throughout the whole body by its own electric signal without any external stimulation. On the contrary, kidney is a special filtration machine which eliminates the nitnagenated waste materials of the body. Due to the coordination of functions of such small machines the whole human body remains active.
Human body is like an organic machine Energy is needed in a machine to do work. In different engines using fuels like petrol., diesel, CNG etc. we convert chemical energy into mechanical energy. Similarly, human body also transforms chemical energy into mechanical and heat energy by food ingestion and respiration. Therefore, human body is like an organic machine in fact. But, in many aspects, human body is more amazing than the most complex machine made by humans. Human body can perform such functions which is not possible for any machine.
For instance- human body develops from only one cell. With the passage of time, this single cell transforms into a complete human body, which is build with thousand billions of cells. But this doesn’t happen in case of any machine. Sometimes functions of the whole body stops due to infirmity of only one part of the body. For example- when function of the heart stops, functions of all other parts of the body stops too, and functions of the brain also stops very quickly.