What is the Nervous System?   (Biology)
Channel: Ali Hassan Memon
Date: 09/01/2018

The Human Nervous System
- Human Neurology
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

The Central Nervous System (CNS)
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 neurones.

The nervous system is a network of nerve cells and, in most animals, a brain. In vertebrates, it also includes a spinal cord. The primary cell type found in the nervous system is the neuron , which has a cell body, containing the nucleus , and long extensions to carry information from one part of the body to another.

The nervous system has two primary functions that are critical in maintaining the life of the organism. First, sensory receptors allow the organism to monitor its external environment and detect changes that occur (for example, an increase in temperature). The nervous system then activates structures such as muscles and glands, which permit the organism to respond appropriately to the environmental changes (moving out of the sun or activating sweat glands). Second, the nervous system also monitors the organism's internal environment, controlling heart rate so that enough blood is delivered to organs, or measuring nutrient levels to signal when an organism needs to obtain food.

While all nervous systems carry out these basic functions, the structure and complexity of the nervous system varies tremendously in different organisms. In vertebrates, it is divided into the central nervous system (CNS), which contains the brain and spinal cord, and the peripheral nervous system (PNS), which is composed of the nerves that carry information to and from the CNS. Invertebrate nervous systems may or may not have distinct peripheral and central regions, but communication with and response to the environment still occurs. Overall, invertebrate systems are much less complex. A vertebrate nervous system may contain a trillion neurons, whereas an invertebrate may have as few as 305.