Unit 3: Neurobiology and immunology - The cells of the nervous system and neurotransmitters at synapses Flashcards
What is the nervous system made up of?
A complex network of nerve cells called neurons which receive and transmit electrical signals (nerve impulses), and glial cells which support and maintain the neurons.
What is a neuron made up?
Cell body, nucleus, dendrites, axon, myelin sheath, node and axon ending.
What does the cell body of a neuron contain?
The cell nucleus and mitochondria to provide energy.
What are dendrites?
Dendrites are nerve fibres that receive nerve impulses and carry them towards the cell body.
What is an axon?
An axon is a nerve fibre which carries impulses away from the cell body. Axon ends in many divisions called axon endings/terminals.
What are long axons covered in and what is its purpose?
A myelin sheath which insulates the axon and increases the speed of the nervous impulse within the fibre.
What is a myelin sheath made up of?
Fatty tissue/material
What is the direction that a nerve will always travel in a neuron?
Dendrite > cell body > axon.
What is myelination?
The development of myelin round the axon fibres of individual neurons.
When is myelination not complete by and what does this result in?
Myelination is not complete at birth and so nervous control increases over the first 2 years as many more neurons are myelinated. (Myelination continues from birth to adolescence). As a result responses to stimuli in the first two years of life are not as rapid or co-ordinated as those of an older child.
How does multiple sclerosis (MS) work?
It is a disease that destroys the myelin sheath causing a loss of co-ordination.
Where are interneurons found and what do they do?
Found in CNS and connect with other neurons.
