Structure and Function of Neurones Flashcards
Structure and function of neurones
- Nerves are called neurones which make up the nervous system
- They are specialised cells that carry messages from one part of the body to another
- The types of neurones exist are sensory neurone , motor neurone and relay neurone
- They consist of a cell body/soma with branching dendrites and axon
- This connects the nerve signal
- Dendrites branch from the cell body and recieve messages
Diagram of all neurones together
What is function of sensory neurone?
They carry messages from PNS to CNS
They have long dendrites and short axons
What is function of relay neurones?
They connect sensory neurones to motor or other relay neurones
They have short dendrites and short axons
What is motor neurones?
They connect CNS to effectors such as muscle or glands
They have short dendrites and long axons
Diagram of nervous system labelled in hand
What is synpatic transmission?
The process if neurons communicating with each other and transmitting messages from one neuron to next
What is a synpase?
Each neurone is separated by a gap called a synpase
Points to remember for synaptic transmission
- Each neurone is separated by a gap called a synpase
- Within a neurone , signals are transferred electrically via axons ; signals between neurones are transferred chemically via neurotramisster
- When an electrical signal releases at the end of neurone (presynpatic terminal) it triggers the release of a neurontramsitter from a tiny sac called synaptic vesicle
- Neurotransmitter diffused across the synpase to the next neurone the point where it hits the next neurone is known as the postsynaptic receptor site
Exam Qs
Label the two areas in the synpase by using the letters
Box 1 - C
Box 2 - D
Outline the structures and processes involved in synaptic transmission;
- In the presynaptic terminal , the neurotransmitters are in a synaptic vesicle
- Release of neurotransmitter into the synaptic cleft when stimulated by nerve impulse (action potential) arriving at the presynaptic terminal
- It binds to the receptor sites on postsynaptic neurone
- It either excitatory (depolarisation) or inhibitory (hypoerpolarisation)
What do neurontransmitter have effect on next neuron?
- Excitatory
- or
- inhibitory effect
What does excitation mean?
When a neurotransmiter increases the positive charge in postsynaptic neurone
and increases the likelihood that neuron will fire and continue to send a sigfnal
What does inhibition mean?
Increases the negative charge of the postsynaptic neurone
This decreases the likehood that neuron wil fire and continue to send a signal
Examples of excitatory neurotransmitter
- Adrenaline (neurotransmitter and hormone)
- Seretonin
