Biopsychology: Neurons and synaptic transmission Flashcards
Types of neurons
Sensory neurons
Motor neurons
Relay neurons
Sensory neurons
Receptor -> CNS
Carry nerve impulses FROM sensory receptors TO CNS
Where are sensory neurones located?
upper epidermis - connected to receptors
Relay neurons (interneurone)
CNC -> CNS
Connect sensory and motor neurones, to other relay neurones
Carry messages from one part of CNS to another
SHORT A SHORT D
Where are relay neurones located?
In CNS
Motor neurons
Carry electrical impulses away from CNS via long axons to muscles/glands. Causes muscle/ glad to react
LONG A SHORT D
Where are motor neurones located?
In CNS
What is a neuron?
A specialised cell
Dendrites
Where info is received and processed
Carry nerve impulses from neighbouring neurones towards the cell body
Axon
Carry electrical impulse AWAY from cell body, down the length of the neuron
Myelin Sheath
An insulating substance which covers axons to help convey the nerve impulse rapidly and protect the axon
Nodes of Ranvier
Gaps in the myelin sheath which speed up transmission of impulse.
Allows action potential to effectively ‘jump’ from node to node
Axon terminal
Transmits a neurotransmitter from one neuron to another
Cell body (soma)
Includes a nucleus containing genetic material
Example of an excitatory neurotransmitter
Adrenaline
Excitatory neurotransmitters will
Will increase the + charge on the post-synaptic neuron, making impulse more likely to fire
Example of an inhibitory neurotransmitter
Serotonin
Inhibitory neurotransmitters will
Will increase the - charge on the post-synaptic neuron, making impulse less likely to fire
What does the firing of an impulse depend on?
The sum of excitatory and inhibitory signals it receives
Net effect excitatory = neuron more likely to fire an impulse
Net effect inhibitory = neuron less likely to fire an impulse
How is an electrical impulse created? (firing of a neuron)
Neuron resting state = inside of cell - charged compared to outside
Neuron activated = inside of cell + charged for split second.
Causing an action potential to occur.
This creates and electrical impulse
Impulse travels down the axon towards the end of the neuron
Synaptic transmission
The process of information transfer across a synapse
Summation
Excitatory or inhibitory effect on neighbouring neuron
Resting state
The state in which there is a negative electrical charge within the neuron
Action potential
a neural impulse; a brief electrical charge that travels down an axon
Synaptic vesicles
Sac-like structures that release neurotransmitters
Outline the structure and processes of synaptic transmission (6 marks)
Structure: neurones are separated by a synapse - a gap between neurons.
1) When an electrical impulse reaches end of neuron
2) Triggers release of NT’s from synaptic vesicles
3) NT chemically diffuses across the synapse and bind to receptors on the post-synaptic receptor site on the next neuron
- Each NT has its own specific molecular structure that corresponds to ‘fit’ into a post-synaptic receptor site
4) Electrical impulse continues and next transmission begins
TALK ABOUT SUMMATION - NT’s can have excitatory/inhibitory effects on neighbouring neuron:
Excitatory (e.g. adrenaline) = increase + charge on post-s neuron, increase likelihood of it firing
Inhibitory (e.g. serotonin) = increase - charge on post-s neuron, decrease likelihood of it firing
5) reuptake: neurotransmitter is reabsorbed in vesicles in pre-synaptic cell after performing function of transmitting electrical impulse
Neurotransmitters
diffuse across synapse to the next neuron
How are signals within neurons transmitted?
electrically
How are signals between neurons transmitted?
Chemically
Synapse
a gap between 2 neurons