Neurons And Synaptic Transmission Flashcards
(28 cards)
what is a neuron?
cells that are specialised to carry neural info throughout the body
How many types of neuron are there and what are they called?
3
sensory
motor
relay
Where is the dendrite located and what is it’s function?
At one end of the neuron and receives signals from other neurons or from sensory receptors.
connected to the cell body.
What does the cell body do?
The control centre of the neuron
What is the role of the axon?
Where the nerve impulse is carried along and terminates at the axon terminal.
What is a sensory neurons?
carries nerve impulses from sensory receptors (receptors for vision, touch and taste) to the spinal cord and brain.
Where are sensory receptors found in the body?
eyes
ears
tongue
skin
What do sensory neurons do?
Convert info from sensory receptors into neural impulses.
When these impulses reach the brain they’re translated into sensations e.g. heat or pain so that the organisms can act accordingly.
How do reflex actions occur?
Not all sensory neurons travel as far as the brain as some terminate at the spinal cord which allows reflex actions to occur quickly without the delay of sending impulses to the brain.
Where are relay neurons located?
Within the brain and the spinal cords.
What do relay neurons do?
Allow sensory and motor neurons to communicate.
What is synaptic transmission?
The process by which nerve impulse passes across the synaptic cleft from one neuron (the presynaptic neuron) to another (the postsynaptic neuron).
What is a synapse?
The conjunction of the end of the axon of one neuron, and a dendrite or cell body of another.
What is the physical gap between the pre-and post synaptic cell membranes called?
This synaptic gap
Where are the synaptic physicals located and what do they do?
At the end of the axon of the nerve cells.
Contain neurotransmitters that assist in the transfer of the impulse.
Describe the process of synaptic transmission.
Action potential arrives at the terminal button at the end of the axon and needs to be transferred to another neuron or to tissue.
Neurotransmitters cross the synaptic gap in order for action potential to reach the synaptic vesicles.
Neurotransmitters release their contents through exocytosis.
The released neurotransmitter disused across the pre- and post synaptic cell + binds to specialised receptors on the surface of the cell that recognise it + are activated by that particular neurotransmitter.
Once activated the receptor molecules produce either excitatory or inhibitory effects on the postsynaptic neuron.
SEE DIAGRAM ON PAGE 151:)
How long does it take for synaptic transmission to take place?
A fraction of a second
Describe the process of “re-uptake“
Neurotransmitter is taking up again by the presynaptic neuron and stored and made available for later release.
What is a neurotransmitter?
The chemical messengers that carries signals across the synaptic, gap to the receptor site on the postsynaptic cell.
What can neurotransmitters be classified as?
Excitatory
Inhibitory
What is an example of excitatory neurotransmitter and what is it referred to as?
Noradrenaline or Acetylcholine
The nervous systems ‘on switches’
What does excitatory neurotransmitters do?
Increase the likelihood that an excitatory signal is sent to the postsynaptic cell, which is then more likely to fire.
What is an example of an inhibitory neurotransmitter and what are they refer to as?
Serotonin or GABA
The nervous system’s ‘off switches’
What are inhibitory neurotransmitter is responsible for?
Calming for mind and body, inducing, sleep, and filtering out unnecessary, excitatory signals.
