biopsychology: neurons and synaptic system Flashcards
(24 cards)
What are neurons?
Nerve cells that process and transmit messages through electrical and chemical signals
What is the function of the cell body in a neuron?
Includes nucleus which contains genetic material of a cell
What do dendrites do?
Carry nerve impulses from neighboring neurons towards the cell body
What is the role of the axon?
Carries impulses away from the cell body
What is the myelin sheath?
Fatty layer that protects axon and speeds up electrical transmission down the axon
What are the Nodes of Ranvier?
Gaps along the axon that speed up transmission by forcing the impulse to jump
What are terminal boutons?
At the end of axons, these make synaptic connections with other cells
What are the three types of neurons?
- Sensory neuron
- Relay neuron
- Motor neuron
What is the function of a sensory neuron?
Carries messages from the PNS to the CNS > responsible for transmitting sensory information
has long dendrites and short axons
What is the role of a relay neuron?
Connects sensory neurons to motor or other relay neurons
has short dendrites and short axons
What does a motor neuron connect?
Connects the CNS to effectors such as muscles and glands > responsible for initiating movement
has short dendrites and long axons
What happens when a neuron is in a resting state? (electrical transmission)
The inside of the cell is negatively charged compared to the outside
What occurs when a neuron fires? (electrical transmission)
The electrical charge of the cell changes to positive, causing an action potential
What is an action potential? (electrical transmission)
A temporary change in electrical charge that creates an electrical signal traveling down the axon
What is synaptic transmission?
The process by which neighbouring neurons communicate with each other by sending chemical messages across the synaptic cleft
chemical transmission: How are messages passed down a neuron?
Messages are passed down the neuron electrically, triggering the release of neurotransmitters from synaptic vesicles
chemical transmission: What are synaptic vesicles?
Tiny sacs that release neurotransmitters at the end of a neuron
chemical transmission: What happens to neurotransmitters after they are released?
They diffuse from presynaptic receptor sites to postsynaptic receptor sites in the next neuron
what causes excitation or inhibition
Stimulation of postsynaptic receptors by neurotransmitters result in either excitation or inhibition of the postsynaptic neuron
What is the effect of excitatory neurotransmitters on the postsynaptic neuron?
The postsynaptic neuron becomes positively charged and is more likely to fire an impulse
What is the effect of inhibitory neurotransmitters on the postsynaptic neuron?
The postsynaptic neuron becomes negatively charged and is less likely to fire an impulse
What determines whether a postsynaptic neuron will fire an impulse?
excitatory and inhibitory influences are summed, if the net effect on the post synaptic neuron is inhibitory, the neuron will be less likely to ‘fire’ and if the net effect is excitatory, the neuron will be more likely to fire
Fill in the blank: If the net effect on the postsynaptic neuron is ________, the neuron will be less likely to fire.
inhibitory
Fill in the blank: If the net effect on the postsynaptic neuron is ________, the neuron will be more likely to fire.
excitatory
