Brief description of Pre and Postsynaptic mechanisms
What are the 6 steps in signal transmission between neurons?
1. Action potential is created at the Axon hillock
2. Signal moves through the axon to the terminal buotons, calcium channels open, CA+ rushes in
3. This causes vesicles to fuse (dock) with the presynaptic membrane
4. Vesicles release neurotransmitter into synaptic cleft, (exocytosis) neurotransmitters open the receiving channels on the post-synaptic cell
5. Ions flow through cleft to post-synaptic neuron
6. Change in potential of post-synaptic membrane (depolarize or hyperpolarize)
What does the Action potential activate at the axon terminal?
Calcium voltage-gated channels
What does CA+ cause in the presynaptic cell?
Vesicles to dock with the presynaptic membrane, and encourages neurotransmitters to be released
When neurotransmitters are released into the synaptic cleft, this is called:
1. What are the two major classes of neurotransmitters?
2. What are the functions of both?
1. Small Molecule and large molecule
2. Small: point to point effects, large: wide-spread effects
What type of gated channel does a neurotransmitter open?
The neurotransmitter _______ across the cleft and binds to ________ in the postsynaptic membrane. _______-gated receptors open and _____ flow through channels, causing a change in the ____-synaptic membrane potential. This change is the __________ ______ which will be integrated with others in the cell body
postsynaptic potential (PSP)
Postsynaptic potentials can _______ or ______ the postsynaptic neuron.
The neurotransmitter effect depends on the _________ _______.
Each neuron has ____ type of ligand-gated channel on its membrane for each ____________ that it receives
Excitatory Postsynaptic Potentials:
Result from ____ flooding the cell
which causes a ____________
this can lead to an _______ _________
Inhibitory Postsynaptic Potentials:
Result from ____ flooding the cell or ____ leaving the cell
Causes a ____________
Can prevent the production of an ______ ______
Different inputs _______ or _______ when they reach the cell body. If the combination of signals is excitatory, ____ channels will open and an action potential can occur, if the signal is inhibitory the action potential will not occur.
Each postsynaptic potential is usually less than ___ mV, and an action potential can be over ___ mV.
Postsynaptic Potentials are _______ _______.
Magnitude is dependent on ______
Signal travels by ______ current flow
Magnitude _______ over moves away from stimulus site
Initiated at synapses of ____ _____ and _______
result in ________ or __________
Activated by _______-gated channels
Magnitude is _____ ___ _____
Signal can travel be _____ current or _________ _________.
Magnitude of signal is __________.
Initiated at _____ _____
Results in __________ only.
What are the two types of summations?
Temporal (one stimulus site, many signals over time) and Spatial (many stimulus sites, many signals)
In a ______ pathway, one presynaptic neuron branches to affect a larger number of postsynaptic neurons.
In a _______ pathway many presynaptic neurons influence a smaller number of postsynaptic neurons.