Neurons And Synaptic Transmission Flashcards
What is a neurone?
A type of cell that relays messages between the CNS and the rest of the body.
Label this diagram of a neurone:
What do dendrites do?
Receive messages.
What does the axon do?
Passes messages to other neurones, muscles or glands.
What does the myelin sheath do?
Protect signals and help speed neural impulses.
What does the axon terminal do?
Form junctions at other cells.
What does the sensory neurone do?
It has ________ dendrites and ________ axons.
Carry nerve impulses from sensory receptors (e.g. vision, taste, touch) to the CNS.
It has long dendrites and short axons.
What does the relay neurone do?
It has ________ dendrites and ________ axons.
Allows sensory neurones and motor neurones to communicate through the CNS.
It has short dendrites and short axons.
What does the motor neurone do?
It has ________ dendrites and ________ axons.
Directly or indirectly controls muscles by carrying impulses from CNS to muscle glands.
It has short dendrites and long axons.
Where are neurotransmitters located?
In synaptic vesicles at the axon terminals.
What are neurotransmitters?
Molecules in the nervous system that transmit messages from neurones to target cells.
What are two examples of neurotransmitters?
-Dopamine: pleasure & motivation.
HIGH LEVELS are linked to schizophrenia symptoms.
-Serotonin: controls emotions.
LOW LEVELS are linked to depression symptoms.
What is synaptic transmission?
The process where a nerve impulse passes through the synaptic cleft (from a pre-synaptic neurone to a post-synaptic neurone).
What is the 5 step process of synaptic transmission?
- An action potential arrives at the axon terminal, waiting to pass to the next neurone.
- When the axon potential reaches the synaptic vesicles, they release neurotransmitters to the synaptic cleft (this is exocytosis).
- Neurotransmitters diffuse across the synaptic cleft, binding to receptor sites on the post-synaptic neurone (completing the process of synaptic transmission).
- The neurotransmitters make it more or less likely the the post-synaptic neurone will ‘fire’.
- Neurotransmitters that don’t bind are broken down by enzymes in the synaptic cleft OR they are reabsorbed into the pre-synaptic neurone (reuptake).
Only ________ neurotransmitters bind to specific ________.
Specific, receptors.