7-chemical synapses

look @ slides for summary

what does action potential of presynaptic cell cause changes to

membrane potetnial of post synaptic cell

how is action potentail generated

if postsynaptic cell membrane is depolarized sufficiently to reach a threshold

electrical synapses

• plasma membrane of pre and post synaptic are held by gap junctions

  • local currents flow rapids from neuronsw

where are electerical synapses found

smooth and cardiac muscle

chemical synpases

signals trasmitted between two neurosn by a diffusible chemical messnager (NEUROTRASMITTERS)

where are chemical synpases found

nervous system

gap between pre and post synaptic neruon in chemical synapse

synaptic cleft

m ovement of chemical synapse

neurotransmitters get exocytosed across a synapse in synaptic vesicles

post synaptic cell has what region

postsynpactic density

steps of chemical synaptic transmittion

action potential moves down axon and releases neurotransmitters from presynaptic axon terminal which affecr local membrane potenial on post synaptic cell

steps of chemical trasnmittion

• presynaptic action potential reaxhes axon terminal depolarized axon opening voltage gated CA2 channels

• ca enters presynaptic termial

• synaptic vesicles docked via snare proteins which are triggered by Ca binding to synaptotagmins caused fusion with presynaptic membrane

• leads to release of neurotransmitters in synaptic cleft

• neurotransmitters bind to ost synaptic neuron and ion channels open and close

to stop chemical action neruotransmitters can

be transported back into presynaptic terminal

diffuse away from synapse

taken up by neighboring cells and degraded

or be broken down enzymatically

synptic delay

breif interval between action potential arriving and time postsynaptic cell affects a change in membrane potential

• caused by gao junctino

neurotransmitters can bind to

ligan gated channles or other receptord that activate second messangers

at excitatory synapse

postsynaptic membrane is depolarizeda

at inhibitory synpase

postsynaptic membrne is hyperpolarized

how to know if synpase is excitatory or inhibitory

type of neurotrasmitter on psot synaptc

types of ion channles associated with the receptors

in excitatory synpase

the local membrsne is depolarized and permiable to small postive ions

• na drivenm in by electrical and conc gradients while K+ oppos

leads to depolarization

excitatory post synaptic potential

potential change in the postsynaptic membrane of an exciratory synpase

inhibitory synpase

local membrane is hyperpolarized

• permiable to Cl or K where Cl is fluxed in or K is fluxed out

  • leads to increased - charge in cell

inhibitory postsynaptic potetnial

potential change in the postsynaptic membrane of an inhibitory synapse