Synapses Sturcture
The beginning and the ends
Terminal buttons release neurotransmitters into the synapse
can be inhibitory or excitatory in some of the next cells
Types
Axodendritic: axon buttons to dendrite
Axosomatic: axon to body or soma
Axonaxonic: axon into another axon (terminal button or axon hillock
Synaptic cleft
space in synapse between postsynaptic and presynaptic cell
Gap Junctions
electrical synapses
There is still space between them (but less), but there are channels between
two cells, allowing for electrical flow
Connexon: channels on both sides & together make gap junctions
very fast
can communicate in both directions (coupling potential
Vesicles & neurotransmitters
Within terminal buttons
balls filled with neurotransmitters
made up of phospholipid bilayer
Synapses Sturcture 1
, Calcium ion channels
VOltage gated
in axon terminal/ buttons
open & flood area with calcium
Bring vesicles close to synapse space
Calcium-dependent exocytosis
Calcium influx causes a chain reaction, where vesicles are pulled closer to
then fused with the cell membrane
Proteins that help fuse vesicles to cell membrane, open the vesicles, and
release the neurotransmitters to the synaptic cleft
Vesicle life cycle
recycle vesicles to be reused
Endocytosis: when the vesicle is fused with the membrane
Exocytosis: vesicle filled with neurotransmitters
Neurotransmitters traveling
is done by simple diffusion
not pulled toward the postsynaptic cell
sometimes doesn't make it and floats away
Drove my chemical forces
there are so many released & in one place that they move to get away from
the densely packed space
Ligand-gated ion channels
chemically gated channels
Neurotransmitters, drugs ec can open it
Synapses Sturcture 2
The beginning and the ends
Terminal buttons release neurotransmitters into the synapse
can be inhibitory or excitatory in some of the next cells
Types
Axodendritic: axon buttons to dendrite
Axosomatic: axon to body or soma
Axonaxonic: axon into another axon (terminal button or axon hillock
Synaptic cleft
space in synapse between postsynaptic and presynaptic cell
Gap Junctions
electrical synapses
There is still space between them (but less), but there are channels between
two cells, allowing for electrical flow
Connexon: channels on both sides & together make gap junctions
very fast
can communicate in both directions (coupling potential
Vesicles & neurotransmitters
Within terminal buttons
balls filled with neurotransmitters
made up of phospholipid bilayer
Synapses Sturcture 1
, Calcium ion channels
VOltage gated
in axon terminal/ buttons
open & flood area with calcium
Bring vesicles close to synapse space
Calcium-dependent exocytosis
Calcium influx causes a chain reaction, where vesicles are pulled closer to
then fused with the cell membrane
Proteins that help fuse vesicles to cell membrane, open the vesicles, and
release the neurotransmitters to the synaptic cleft
Vesicle life cycle
recycle vesicles to be reused
Endocytosis: when the vesicle is fused with the membrane
Exocytosis: vesicle filled with neurotransmitters
Neurotransmitters traveling
is done by simple diffusion
not pulled toward the postsynaptic cell
sometimes doesn't make it and floats away
Drove my chemical forces
there are so many released & in one place that they move to get away from
the densely packed space
Ligand-gated ion channels
chemically gated channels
Neurotransmitters, drugs ec can open it
Synapses Sturcture 2
