Lecture 3: Synapses

What are the three physical elements of an electrical synapse

presynaptic neuron, gap junction, postsynaptic neuron

What are the three physical elements of a chemical synapse

presynaptic neuron, synaptic cleft, postsynaptic neuron

space between an electrical synapse

gap junction

space between a chemical synapse

synaptic cleft

target of a synapsing neuron

postsynaptic neuron

three locations of synaptic contact

axodendritic, axosomatic, axoaxonic

advantage of electrical synapse

very fast

electrical synapse location

heart muscle, smooth muscle, retina

electrical synapse purpose

synchronization of muscle contraction

neuron connection in electrical synapse

ion channel pore, connexon

neuron connection in chemical synapse

synaptic cleft

chemical synapse location

between neurons, between neurons and muscle cells

what happens at chemical synapses if the Ca 2+ channels are blocked

transmitter is not released

how does AP lead to opening of Ca2+ channels

Ca2+ channels are voltage sensitive

T or F: effect of AP is always excitation of postsynaptic element

false

depolarization

EPSP, increased Vm, moves toward threshold

hyperpolarization

IPSP, decreased Vm, moves away from threshold

T or F: chemical synapses are faster than electrical synapses

false

slow signaling

metabotropic, indirect communication

fast signaling

ionotropic, direct communication

IPSP

inhibitory postsynaptic potential

EPSP

excitatory postsynaptic potential

how does AP cause release of neurotransmitter

opens Ca2+ channels, presynaptic terminal attaches to presynaptic membrane, release of neurotransmitter

direction of electrical synapse

bidirectional

direction of chemical synapse

unidirectional