Neurones And Synaptic Transmission Flashcards
(23 cards)
What is the primary means of communication in the nervous system?
100 billion neurons
80% of which provide communication.
What are the three types of neurons?
- Sensory neurons
- Relay neurons
- Motor neurons
What structure in a neuron carries nerve impulses towards the cell body?
Dendrites
What carries impulses away from the cell body in a neuron?
Axon
What is the function of the myelin sheath?
Protects the axon and speeds up electrical transmission
What are the gaps in the myelin sheath called?
Nodes of Ranvier
What is the role of terminal buttons in a neuron?
Communicate with the next neuron across the synapse
Where are the cell bodies of motor neurons located?
Central nervous system (CNS)
Where are sensory neurons located?
Outside of the CNS, in the peripheral nervous system (PNS) in clusters known as ganglia
What percentage of neurons are relay neurons?
97%
What charge does the inside of a neuron have at rest?
Negatively charged
What happens when a neuron is activated by a stimulus?
The inside of the cell becomes positively charged, causing an action potential
How do neurons communicate with each other?
Chemically across the synapse
What triggers the release of neurotransmitters?
The electrical impulse reaching the presynaptic terminal
What are neurotransmitters?
Chemicals that diffuse across the synapse to the next neuron
What is the function of postsynaptic receptor sites?
Convert the chemical message back into an electrical impulse
True or False: Neurotransmitters can travel in both directions across the synapse.
False
What is an example of a neurotransmitter that causes muscle contraction?
Acetylcholine (ACh)
What effect does serotonin have on the receiving neuron?
Inhibitory effect
What does adrenaline do to the postsynaptic neuron?
Causes excitation
What determines whether a postsynaptic neuron will fire?
The process of summation
Fill in the blank: The inside of the postsynaptic neuron becomes _______ if the net effect is excitatory.
Positively charged
What is required for the action potential of the postsynaptic neuron to be triggered?
The sum of the excitatory and inhibitory signals must reach the threshold
