PHY2011 Lecture Notes - Lecture 13: Acetylcholine, Nuclear Receptor, Axon Terminal
20 Jun 2018
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Week 5 L1 (T3L5) -autonomic nervous system & the endocrine
system (GPCRs and intracellular receptors)
Organs -slow control system therefore GPCR
Autonomic nervous system
oDivision of peripheral nervous system
oControls, sends and receives info from internal organs and tissues
oNot under conscious control
oWide spread effects: enables coordination of many tissues & organs
oTwo divisions: sympathetic and parasympathetic
Efferents: Motor neurons
Afferents: Carry information in
Enteric NS- focuses only on Gut (not focused upon in this unit)
Somatic NS-skeletal muscle
oNerves run directly from CNS to skeletal muscle
oAα class -Myelinated and thick diameter
Autonomic NS -smooth muscle, glands and cardiac muscle
oSympathetic NS -Fight/flight -promotes production of cAMP
oParasympathetic NS -quiescence -suppresses production of cAMP
oNerves to from CNS to ganglion (bundle of nerve cells) THEN to tissues and organs
oSlower than somatic control -B class (pre) and C class (post)
Small diameter neurons
Non-myelinated post-ganglion
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- Diffuse synapses -release of transmitters along axon to spread the
message
myelinate pre-ganglion
- Discrete synapses -release of synapses only at axon terminal
Why? b/c we only want to control one organ at a time (discrete), but once
we get to the organ, we want to control all the cells of that organ (diffuse)
Transmission
oACh (Acetylcholine) used in first step (from CNS to ganglion)
oAct upon Nicotinic receptors (to transmit to neurons in ganglion)
oBut post-ganglion, sympathetic and para sympathetic systems differ
Sympathetic:
- Neurotransmitter: Noradrenaline (NA)
- Receptors: α- and β-Noradrenergic receptors (α-NARs and βNARs)
- Both G-protein
- Two types of
Parasympathetic:
- Neurotransmitter: ACh
- Receptor: Muscarinic Acetylcholine receptors (mAChR) (linked to G-
protein -slower but more diverse effects)
- Two types of mAChRs -activate two different G-proteins
ocAMP pathway and PLCβ pathway (Ca2+ )
find more resources at oneclass.com
find more resources at oneclass.com
