Block 1 Lecture 11 Flashcards
(21 cards)
what happens in an electrical synapse
Conduct electricity between 2 cells, a change in voltage in one cell spreads to adjoining cell
what are some characteristics of electrical synpases
the gap is smaller than chemical synapse
very fast bidirectional movement
what are connexins
proteins that form gap junctions
what is the role of connexins in heart muscle
connexion 43 forms gap junctions that electrically couple neighboring cells to coordinate cardiac action potential
what happens in a chemical synapse
-presynaptic neuron secretes a chemical neurotransmitter into cleft between cells
-chemical selectivity activates receptors on postsynaptic cell surface
-receptor activation causes a change in the postsynaptic cell
(communication occurs in one direction)
what does the presynaptic cell do
makes and packages neurotransmitters, releases neurotransmitters
what does the postsynaptic cell do
makes and displays receptors, responds to neurotransmitter
what is the mechanism for a chemical synapse
- membrane potential depolarizes in presynaptic cell
- fusion of neurotransmitter containing vesicles into synaptic cleft
- Neurotransmitter binds to postsynaptic receptors
- change in open/close of ion channels in postsynaptic cell membrane
- change in membrane potential in post synaptic cell
- response may be inhibitory or excitatory
what would cause excitation
increasing Na+ channels
decreasing K+ channels
what does excitation cause
depolarization
what would cause inhibition
increasing K+ channel
what does inhibition cause
hyperpolarization
what type of receptors are channel receptors
ionotropic
what type of receptors are seven helix receptors
metabotropic
what is an ionotropic receptor
contains a neurotransmitter binding site and an ion channel
what is a metabotropic receptor
contains a neurotransmitter binding site coupled with a G protein that can relay signal to a separate ion channel
what does PAG do
converts glutamine to glutamate
what does vGLUTS do
transports glutamine and pumps protons out other way using proton gradient
what does v-ATPase do
its a proton pump
what are some characteristics of neurotransmitter fusion and release
it is voltage dependent, highly selective, and calcium dependent
how do Ca2+ channels open
by depolarization of presynaptic cell
