PHY2011 Lecture Notes - Lecture 10: Exocytosis, Endocytosis, Microtubule
20 Jun 2018
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Week 4 L1 (T3L2) -Chemical synaptic signalling
Only type of signalling that is unique to neurons
Use neurotransmitters
Distances are short
Effects are short or relatively long lasting
Two types
oDiscrete
Precisely controlling where actions are to be exerted
oDiffuse
Forms bulges of varicosities where signals are released to nearby cells
Effects cells with receptors
Structure of the synapse
oPoint of functional contact -NOT PHYSICAL (there’s a gap)
oPost synaptic-density- location of a high volume of receptors
oCleft bridged by several proteins
oEnsures precise alignment
oIf cell is slightly misaligned, release of chemicals not as efficient
oNeuroligin and Neurexin are the most important of the connecting proteins -form a
bridge
Chemical neurotransmitters
oChemical transmission bridges the synaptic cleft
oFive criteria to confirm this:
find more resources at oneclass.com
find more resources at oneclass.com
Synthesis of the neurotransmitter in the presynaptic nerve terminals (or
cell body)
Storage of neurotransmitter in secretory vesicles. (except for gases)
Regulated release of neurotransmitter into the synaptic cleft.
Receptors on postsynaptic membrane to bind neurotransmitter (except for
gas molecules -they can diffuse through membrane).
A means for termination of the action of released neurotransmitter
Broken into two classes: Peptide transmitters and non-peptide transmitters
oPeptide transmitters first to be discovered- -meet all above criteria
More integrative transmission
Need more APs
oNPT are most of the exceptions -produced in the cell body
More efficient
Advantages of vesicles
oNeurotransmitter concentrated rather than floating around
oNeurotransmitter prevented from degradation (by enzymes)
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Only type of signalling that is unique to neurons. Precisely controlling where actions are to be exerted: diffuse. Forms bulges of varicosities where signals are released to nearby cells. Chemical neurotransmitters: chemical transmission bridges the synaptic cleft, five criteria to confirm this: Synthesis of the neurotransmitter in the presynaptic nerve terminals (or cell body) Storage of neurotransmitter in secretory vesicles. (except for gases) Regulated release of neurotransmitter into the synaptic cleft. Receptors on postsynaptic membrane to bind neurotransmitter (except for gas molecules -they can diffuse through membrane). A means for termination of the action of released neurotransmitter. Broken into two classes: peptide transmitters and non-peptide transmitters: peptide transmitters first to be discovered- -meet all above criteria. Need more aps: npt are most of the exceptions -produced in the cell body. Advantages of vesicles: neurotransmitter concentrated rather than floating around, neurotransmitter prevented from degradation (by enzymes, release of nt can be controlled.
