chapter 2 Flashcards
(36 cards)
What is a Synapse?
Specialized junction as a point of communication between two neurons.
Define Reflex Arc.
The circuit from sensory neuron to muscle response.
What is Temporal Summation?
A cumulative effect of repeated stimuli within a brief time.
What is a Presynaptic Neuron?
Neuron that delivers transmission to another neuron.
What is a Postsynaptic Neuron?
Neuron that receives transmission from another neuron.
Define Spatial Summation.
Combination of effects of two or more synapses onto a single neuron.
What is Synaptic Cleft?
The space between the presynaptic and postsynaptic neuron.
What are Neurotransmitters?
Chemicals released by neurons that affect other neurons.
What does MAO stand for?
Enzyme that converts catecholamines and serotonin into synaptically inactive chemicals.
What are Vesicles?
Tiny nearly spherical packets filled with neurotransmitter molecules.
What is Exocytosis?
A release of neurotransmitter from the presynaptic neuron into the synaptic cleft.
What are Transmitter-Gated Channels?
Ion channels that open temporarily when a neurotransmitter binds to it.
What is a G protein?
A protein coupled to Guanosine Triphosphate, an energy storing molecule.
What is a Second Messenger?
A chemical that, when activated by a neurotransmitter, initiates communication to many areas within the neuron.
What is the role of Acetylcholinesterase?
The choline diffuses back to the presynaptic neuron to form acetylcholine again.
Define Reuptake.
The presynaptic neuron takes up much or most of the released neurotransmitter molecules intact and reuses them.
What are Transporters?
Molecules that transport neurotransmitters back to the presynaptic neuron.
What are Autoreceptors?
Receptors sensitive to the same transmitter they release, inhibiting further synthesis and release.
What is a Gap Junction?
At electrical synapse, the membrane of one neuron comes into direct contact with the membrane of another.
What is an Excitatory Postsynaptic Potential (EPSP)?
Graded depolarization resulting from a flow of sodium ions into the neuron.
What is an Inhibitory Postsynaptic Potential (IPSP)?
Graded hyperpolarizations produced by the flow of negatively charged chloride ions into the cell.
What did Loewi’s Experiment involving frog hearts demonstrate?
Communication across the synapse occurs via chemical means
List the steps of Chemical Events at the Synapse.
- Neuron synthesizes neurotransmitters
- Action potentials travel down the axon
- Calcium enters the presynaptic terminal
- Calcium releases neurotransmitters into the synaptic cleft
- Molecules diffuse across the cleft.
How are Neurotransmitters released?
Depolarization opens voltage-dependent calcium gates in the presynaptic terminal.
