Neurons and synaptic transmission Flashcards
What are neurons?
Nerve cells that process and transmit messages through electrical and chemical signals
What is the role of sensory neurons?
Carry messages from PNS to CNS
What is the role of relay neurons?
Connect sensory neurons to motor and other relay neurons
What is the role of motor neurons?
Connect CNS to effectors (e.g. muscles and glands)
What is the order of neurons?
Sensory > Relay > Motor
What is the structure of sensory neurons?
Long dendrites
Short axons
What is the structure of relay neurons?
Short dendrites
Short axons
What is the structure of motor neurons?
Short dendrites
Long axons
Where are sensory neurons located?
Fully PNS
Where are relay neurons located?
Fully CNS
Where are motor neurons located?
PNS and CNS
Which neuron does not have a myelin sheath?
Relay neurons
What is the function of the nucleus (neurons)?
Contains genetic material of the cell
What is the function of dendrites (neurons)?
Carry nerve impulses from neighbouring neurons towards cell body
What is the function of the axon (neurons)?
Carries nerve impulses away from the cell body, down the length of the neuron
What is the function of the myelin sheath (neurons)?
Protects the axon and speeds up electrical transmission of the impulse
What is the function of nodes of ranvier (neurons)?
Speed up transmission of the impulse, by forcing it to jump across the gaps along the axon
What is the function of terminal buttons (neurons)?
Communicate with the next neuron in the chain, across a synapse
How are signals WITHIN neurons transmitted?
Electrically
How are signals BETWEEN neurons transmitted?
Chemically
What are neurotransmitters?
Brain chemicals that relay signals across the synapse from one neuron to another
What is excitation?
When a neurotransmitter increases the positive charge of the postsynaptic neuron, it increases the likelihood that the postsynaptic neuron will pass on the electrical impulse
What is inhibition?
When a neurotransmitter increases the negative charge of the postsynaptic neuron, it decreases the likelihood that the postsynaptic neuron will pass on the electrical impulse
What is summation?
The process that determines whether or not action potential will be generated by the combined effects of inhibitory and excitatory signals
What is synaptic transmission?
The process by which neighbouring neurons communicate with each other by sending chemical messages across the synpase
How does synaptic tranmission occur?
- Action potential travels down the axon of the presynaptic neuron
- Triggers release of neurotransmitter from synaptic vesicles
- AP to postsynaptic neuron, where neurotransmitters binds to receptor cells
