Human Biology (Year 12) - Nervous Transmission
The nervous system is the communication system and control centre of the body. With the endocrine system, it maintains a constant internal environment within the body. It is composed of two divisions;
The Central Nervous System (CNS) which is made up of the brain and spinal cord
The Peripheral Nervous System (PNS)
The nervous system is comprised of many roles.
Has receptors to detect stimuli (changes to the internal and external environment)
Transmits nerve impulses from receptors to the brain
Analyses sensory input from different receptors
Stores information (memory)
Transmits nervous impulses from the brain to muscles and glands in order to respond to stimuli
What are neurons?
Image: Neuron image, Image by Dhp1080, Sourced Under a Creative Commons 4.0 License from Wiki Commons
Neurons or nerve cells are the anatomical and functional units of the nervous system; they are the only part of the body that conducts nerve impulses. There are three key components to a neuron;
Cell body – The cell body consists of a mass of neuroplasm surrounding the nucleus; it contains the nucleus and directs the activities of the rest of the cell – the axon and dendrites extend from the cell body
Dendrite – The dendrite is a branching structure, and acts to carry nerve impulses towards the cell body, referred to as an afferent process
Axon – The axon is typically long and less branching; it acts to carry nerve impulses away from the cell body, known as the efferent process