Sympathetic NS Flashcards
Where is the cell body located in PREganglionic neurons?
Where is the cell body located in POSTganglionic neurons?
Cell body in CNS
Cell bodies clustered together in GANGLIA
(express nACh R’s)!
Where are SYMPATHETIC GANGLIA located?
Where are PARASYMPATHETIC GANGLIA located?
S.G = NEAR SPINAL CORD (lined up outside)
[i.e. paravertebral ganglia]
PS.G = NEAR TARGET TISSUE
What is one unique factor of sympathetic neurons?
Show a high level of DIVERGENCE in synaptic connections
THUS, enabling rapid, widespread activation
Where do ganglion arise from?
NEURAL CREST CELLS
(migrate out to form ganglion)
- 1st links in all 3 systems are EXCITATORY (have ACh transmitter)
(All 3 have nACh R)
- 2nd links in the autonomic systems are the postganglionic neurons, which release NA or ACh onto smooth muscle in target tissue or organ
The transmitter action on target is either excitatory or inhibitory, DEPENDING ON GPCR COUPLING!
For a given target organ, if the effect of the Sympathetic system is EXCITATORY, then effect of the Parasympathetic system will be..
What does this allow?
INHIBITORY
This allows PRECISE CONTROL OF ORGAN FUNCTIONS!
What are the 2 EXCITATORY R’s?
Alpha 1
Beta 1
What are the 2 INHIBITORY R’s?
Alpha 2
(Decreases insulin release, using Kir activation by G-proteins to cause hyperpolerisation (& relaxation)!)
Beta 2
(Increases Ca+ export from cell, resulting in smooth m. relaxation!)
SYMPATHETIC NS =
FLIGHT OR FIGHT RESPONSE!
Gq GPCR
Gs GPCR
