Ion Channels
______ are protrusions from the dendrite which contact the axon terminals to receive synaptic input
Dendritic spines
How many substances are recognized as neurotransmitters?
100+
Neurotransmitters bind to _____ to complete transmission
receptors
glia cells remove synapses by a process called?
pruning
which ion regulates neurotransmitter release?
Ca2+
GABA is the primary ______ neurotransmitter in the central nervous system, while Glutamate is the primary ______ neurotransmitter
inhibitory; excitatory
presynaptic: “_______” neuron that sends information
postsynaptic: “________” neuron that receives information
upstream; downstream
Why is summation necessary?
Single presynaptic inputs are usually insufficient to trigger an action potential
What type synapse is the most “powerful” in terms of neurotransmission? (hint: axo-.....)
axo-axonic
Epinephrine functions as both a neurotransmitter and a ______
hormone
Neurotransmitters are present in ______terminals and are released in amounts sufficient to exert a defined action on the _______neuron
presynaptic; postsynaptic
Would this signal be electrical or chemical?: a heartbeat (to stay alive all the time)
electrical not chemical
Ligand-gated channels open when neurotransmitters bind to the:
extracellular receptor site
Differences between Ionotropic receptors and metabotropic?
I: Directly open ion channels when neurotransmitter binds
M: Activate G proteins and signaling cascades
During GABAa transmission, the entry of Cl⁻ causes a ______ polarization and an ______ postsynaptic potential
hyperpolarization; inhibitory
Botulinum toxin prevents synaptic transmission by:
Cleaving SNARE proteins...
Botulinum toxin prevents synaptic transmission by cleaving SNARE proteins, which blocks synaptic vesicle fusion and stops neurotransmitter release.
Ion channels are typically _____ so, they will often reject some ions, resulting in _______ ______
charged; selective permeability
This receptor subtype requires both glutamate binding and postsynaptic depolarization to remove a Mg²⁺ block, allowing Ca²⁺ influx that contributes to long term synaptic plasticity.
NMDA receptor
Although ___________ are important for the energy of ion exchangers, _______is what they primarily rely on
electrochemical gradients, ATPase Pump
What is endocytosis?
This process retrieves vesicle membrane after neurotransmitter release so it can be reused.