The Synapse and Other cells in the nervous system Flashcards
What is the synapse?
A gap between cells.
Vesicles bind to the cell membrane and release their neurotransmitter into the synaptic cleft.
What does the presynaptic neuron do?
Sending/sends
What does the postsynaptic neuron do?
Receiving/receives
Neurotransmitters bind to receptors on the postsynaptic dendrites.
What are glial cells?
Known as support cells.
Glial means ‘glue’
They have lots of functions.
What are the glial cells functions?
Provide nutrients
Remove waste
Provide structural support to neurons
Form myelin
Speed up neural communication
Glial cells: astrocytes functions?
Form the immune system of the brain
Fight infections
Remove waste
Structurally support the neurons and provide nutrients
Glial cells: microglia functions?
Form the immune system of the brain
Fight infections
Remove waste
Glial cells: oligodendrocytes functions?
Form the myelin around axons
Speed up the transmission of messages
In the CNS (brain and spinal cord) they wrap their fat tissue around axons
Glial cells: Schwann cells function?
Form the myelin around axons
Speed up the transmission of messages
In the peripheral nervous system, they wrap their fat tissue around the nerves
What is the action potential?
A brief electrical charge that moves down the axon.
The neuron either fires or it doesn’t.
How does the action potential work?
Cells have an electrical charge called the resting potential.
Ions pass back and forth across the cell membrane where the cell allows this.
Places, where particles might get in or out, are called ‘gates’ or gated channels’.
What is the resting membrane/potential?
There are charged particles everywhere.
But mostly positive ones on the outside and mostly negative ones on the inside.
There is a difference or potential for electrical flow from one place to another.
What is a neurotransmitter?
There are 2 basic types:
Excitatory: likely to increase a cell’s firing rate (more action potentials)
Inhibitory: likely to decrease a cell’s firing rate (fewer action potentials)
The action potential steps?
Stimulus
Depolarization
Action potential
Repolarization
Refractory period
Resting-state
Where do neurotransmitters originate?
They are released from neurons when vesicles bind to the presynaptic membrane.
What happens to extra neurotransmitters?
Some drift away.
Some get taken back into the pre-synaptic neuron (recycled).
Types of NT
Acetylcholine
Dopamine
Serotonin
Norepinephrine
GABA
Glutamate
What is an agonist?
A molecule mimics (copies) a neurotransmitter action.
Ex: cocaine, blocks the reuptake of dopamine.
What is an antagonist?
A molecule that inhibits or blocks a neurotransmitter’s action.
Ex: botox, prevents the movement of the face muscles.
