Action Potentials And Synapses Flashcards
What is the steps of an action potential?
-Electric impulse travels along and axon carrying information.
-Once there is enough excitatory signals a potential is triggered.
-Positive ions diffuse into the neurone making it positively charged.
What is the all or nothing principle (after a action potential)?
-If depolarisation is not enough to reach the threshold then an action potential is not produced.
-When the neurone is stimulated positive ions enter (depolarisation).
-Once we get a positive balance the positive ions are pushed out.
-Negative ions rush in and become hyperpolarised before going back to normal.
What is the process of synaptic transmission?
-Axon potential comes down the axon terminal.
-Vesicles full on neurotransmitters move to the edge of the cell and release NT into the synaptic gap.
-The NT drifts across the gap and bonds to a receptor.
-When enough are filled a new actions potential/ nerve impulse starts in the next neurone.
-Some of the NT is degraded by enzymes in the synaptic gap and some is carried back into the presynaptic neurone by transporter proteins (reuptake).
What is the process of reuptake?
-The axon terminal reabsorbs (via transporter proteins) some of the neurotransmitters once there have carried their message.
-An enzyme is usually used to break down the NT so this can happen.
Why does reuptake happen?
To regulate how many signals are sent.
What is a neurotransmitter?
Chemical messengers that act between the neurones in the brain to process thoughts and memories.
What is a synapse?
A gap between two neurones.
What is a receptor?
Fits like a key to a certain neurotransmitter so a message can be passed on.
