Nervous System In Focus

Overview

The brain performs a lot of things for a human body to function well such as controlling what a person thinks and feel, learning and remembering things, the way a person moves and talk, and some other things such as the beating of the heart, digestion of the food and etc. Thus, it is very important to have an understanding on how this amazing brain or the nervous system works.

The nervous system is essentially a biological information highway, and is responsible for controlling all the biological processes and movement in the body, and can also receive information and interpret it via electrical signals which are used in this nervous system

It consists of the Central Nervous System (CNS), essentially the processing area and the Peripheral Nervous System which detects and sends electrical impulses that are used in the nervous system


Central Nervous System

The Central Nervous System is effectively the centre of the nervous system, the part of it that processes the information received from the peripheral nervous system. The CNS consists of the brain and spinal cord. It is responsible for receiving and interpreting signals from the peripheral nervous system and also sends out signals to it, either consciously or unconsciously. This information highway called the nervous system consists of many nerve cells, also known as neurons

The Nerve Cell

PhotoCredit: websters-online-dictionary.org

Each neurone consists of a nucleus situated in the cell body, where outgrowths called processes originate from. The main one of these processes is the axon, which is responsible for carrying outgoing messages from the cell. This axon can originate from the CNS and extend all the way to the body's extremities, effectively providing a highway for messages to go to and from the CNS to these body extremities.

Dendrites are smaller secondary processes that grow from the cell body and axon. On the end of these dendrites lie the axon terminals, which 'plug' into a cell where the electrical signal from a nerve cell to the target cell can be made. This 'plug' (the axon terminal) connects into a receptor on the target cell and can transmit information between cells

Definition

The nervous system is an organ system that contains a network of specialized cells called neurons. This is the master controlling and communicating system of the body. It coordinates the action of an animal and transmits signals between the different parts of the body. Every thought, movement and emotions reflect the activity of the nervous system.

Communication

The "All-Or-None-Law" applies to nerve cell communication as they use an on / off signal (like an digital signal) so that the message can remain clear and effective from its travel from the CNS to the target cell or vice versa. This is a factor because just like electricity signals, the signal fades out and must be boosted along its journey. But if the message is either 1 or 0 (i.e.) on or off the messages are absolute.

Classification of Neurons

Interneurones - Neurones lying entirely within the CNS

Afferent Neurones - Also known as sensory neurones, these are specialised to send impulses towards the CNS away from the peripheral system

Efferent Neurones - These nerve cells carry signals from the CNS to the cells in the peripheral system

Functions of the NERVOUS SYSTEM

1. To monitor changes that takes place inside and outside the body. The nervous system utilizes the million sensory receptors to carry out this function. Any changes or stimuli occurring are noted by the nervous system and the gathered data is now called a sensory input.
2. Another important function of the nervous system is to process and interpret the sensory input or gathered data. It is the working of this system to make decision about what should be done at each moment. This is the process known as INTEGRATION.
3. As the nervous system has reached a decision of what response and appropriate action to be done in response to the stimuli, it then effects a response by activating muscles or glands through motor output.

These functions of the nervous systems works hand in hand. The process starts with the sensory input. The nervous system then processes and integrates this information. The nervous system then  sends motor output to response.