Nervous system, CNS and Neurons
Neurons are nerve cells in our body and part of the nervous system NS. It consists of the central nervous system CNS and the autonomic nervous system ANS. ANS regulates our body processes like digestion and heart rate, without our explicit control and without external stimulii. CNS consists of the brain and the spinal chord.
There are many types of neurons. Each type resides in a different part of the body and does one function. Signals are passed on by the neurons. Signals can be electrical or chemical. Neurons carry electrical signals (very small impulses in potentials in nerves ) are carried to the brain and from brain to different parts of the body. Signals can be transmitted from one part of the body to another part. These signals are interpreted as information. The signals travel hundreds of meters per second.
Different regions (structures) of neurons have different functions.
Functions of Neurons:
1 Sensory neurons: First of all, they transmit impulses inwards from our five sensory organs (interfacing the environment and external world). These impulses are generated by the sensory organs on receiving some external stimulations. There are receptors to catch them.
2 Relay neurons : From CNS, they retransmit the electrical impulses (from stimulii) to other nerves. These are also called communication neurons.
3 Motor neurons transmit electrical signals from CNS to muscles and glands all over the body. These neurons can stimulate muscles to contract or relax for example.
4 Computation neurons : They extract and process information coming in from sensory neurons. They compare this information with that present in the memory, and depending on the information, they plan and execute behaviour (response to the stimulii). There are many types of computation neurons.
These neurons are organized into signalling circuits closely. One sensory neuron can affect multiple motor neurons. One motor neuron is affected by multiple sensory neurons. Interneurons connects these two types of neurons.