Biopsychology : The Structure And Functions Of Neurons Flashcards
What are neurones?
The nervous system is composed of cells called neurons (nerve cells). There are three types of neurons (sensory, relay, motor). They are distinct yet share some basic structural features.
Describe the main structural features of a neurones Cell Body.
This is the part of the neurone which contains the nucleus (storage of genetic information).
Describe the main structural features of a neurones Axon.
This is the long threadlike part of the neuron, along which the nerve impulse (electric signal) is conducted from the cell body to other cells.
Describe the main structural features of a neurones Dendrites.
These are the the short branched (tree like) extensions that project from a neurons cell body. They receive neurochemical information from adjacent neurons and they transmit a nerve impulse towards the cell body & axon.
Describe the main structural features of a neurones Myelin Sheath.
This is the fatty layer that surrounds the axon of most neurones. It insulates the neurone and helps the nerve impulse travel down the axon.
Describe the main structural features of the node of Ranveer.
These are the gaps between the myelin sheath along a neurones axon. They also help to speed up the nerve impulse as it travels down the axon, away from the cell body.
Describe the main structural features of the Axon Terminal.
This is the end of the neurone and where the nerve impulse completes its journey. The gap between the axon terminal of one neurone and the dendrites of an adjacent neurone is called the synapse.
Outline the function of a Sensory neurone.
To receive information from sensory receptors (PNS) and send information to the CNS (brain and spinal cord).
Outline the Structural features of sensory neurones.
> The dendrites of a sensory neurone are specialised to receive sensory information. (Sensory receptors)
Long dendrites and short axon
Outline the function of a Relay neurone
To allow communication between sensory and motor neurones. The CNS is made up of relay neurones — its other function is to facilitate higher order thinking.
Outline the structural features of Relay Neurones.
> Short dendrites and short axon
No myelin sheath or nodes of Ranvier
Only found in brain and spinal cord
Outline the function of the Motor neurone.
To receive information from the relay neurones and communicate with effectors (e.g muscles).
Outline the structural features of Motor neurones.
> Short dendrites and long axon
