[Biology Class Notes] on Human Nervous System Pdf

The Human Nervous System is primarily divided into two components – the peripheral Nervous System (PNS) and the Central Nervous System (CNS). The CNS is essentially the hub of the organism’s body, which includes parts of the brain and spinal cord. The System is responsible for regulating command, coordination, information, and the integration which influences numerous activities of the body. 

The other component of the Nervous System, as mentioned above, is PNS. The PNS is made up of Neurons, plus other parts that are outside CNS. The signals that are received by CNS are primarily from PNS which plays the supporting role. The Neurons are the components of PNS that are vital for processing as well as transferring information to muscles, glands, and Nerve Cells. There are various billions of Neurons that are present in the body that have extensions like Axons and the Dendrites.

The Neurons are Nerve Cells having the Cell body called soma. Neurons produce a significant chunk of protein and these proteins get absorbed in the soma. The Nerve Cells consist of two distinctive and important components – Axons and Dendrites. The processes of short branching are called Dendrites while the processes that are longer than Dendrites are called Axons. This is the fundamental structural difference between the Axons and the Dendrites.

The Dendrites are specialized forms of short fibrous branches which extend from the Nerve Cell body. The function of the dendron is to accept and process the incoming information that takes place within Dendrites. The incoming signals of dendron function belong to two categories – inhibitory which prevents the Neurons from taking the trigger and excitatory which makes the Neurons take the trigger. 

The single Neuron might consist of multiple sets of Dendrites and it can receive a lot of information from input signals. The impulse is primarily dependent on the number of inhibitory and excitatory signals it receives. If a Neuron rejects the incoming trigger, the Nerve impulse is shifted down to the Axon. 

What is the Axon?

The Axon is a tail-like projection of a Nerve Cell, also called the Nerve fiber which conducts electrical impulses within the body which is away from the soma or Nerve Cells. The impulses typically come from the Cell body at a special junction named as Axon hillock. The Axons are the main transition lines which bundle up for creating the Nerve. One of the differences between Dendrite and Axon is the fatty substance named myelin which only covers the Axon. 

Some of the main differences between Axon and Dendrite are as follows. Axon originates from the discharging end of Neuron while Dendrite originates from the receiving end of Neuron. You can only find one Axon per Nerve Cell whereas there are various Dendrites within a Nerve Cell. The Axon has the long-tail structure and Dendrite has short, fibrous, root-like structure. The Axon has uniform thickness throughout its length while Dendrite consists of tapering end having root-like branches.