Quiz #1: ANS (10) Flashcards
What are the functional classes of neurons?
- afferent neurons
- interneuron
- efferent neuron
Skeletal muscles are innervated by what type of neurons?
motor neurons
What are the parts that make up the autonomic nervous system?
- sympathetic
- parasympathetic
- enteric
What is the organization of the ANS?
Pathway of 2 neurons (pre/postganglionic) and 2 synapses
Ganglion: cluster of neuronal cell bodies outside of CNS (where you can find the second neuron of ANS)
Where is the cell body of the preganglionic neuron found?
CNS (brain/spinal cord)
Where is the cell body of the postganglionic neuron found?
autonomic ganglia
What is collateral ganglia?
aka prevertebral ganglia
when the preganglionic fiber does NOT synapse to the postganglionic fiber in the sympathetic chain
instead form synapse in the collateral ganglia
innervate viscera (INTERNAL ORGANS)
What is the sympathetic nervous system?
- preganglionic fibers original from lateral horn of the T1-L2 spinal cord (SHORT)
- postganglionic fiber found in sympathetic ganglia chain/trunk (LONG)
- exceptions: some sympathetic ganglionic neurons found in prevertebral ganglia
What is the pathway involving the first synapse (between pre/postganglionic fiber)?
- Action potential comes down presynaptic fiber to terminal
- open calcium channel for depolarization
- triggers release of ACh (NT)
- goes to cleft and binds to ACh receptors on postsynaptic cell
What is ChAT and what does it do?
choline acetyltransferase
synthesis of ACh
choline + acetyl CoA = ACh
What is the pathway involving the second synapse (between postganglionic fiber/effector organ)?
- Action potential comes down postsynaptic fiber to terminal
- open calcium channel for depolarization
- triggers release of NE (NT)
- NE bind to receptors on effector organs OR diffuse into blood OR exogenous uptake (not through receptors) OR reuptake
Where is ACh synthesized?
At presynaptic cell terminal
What is the sympathetic preganglionic neurotransmitter?
Acetylcholine (ACh)
What is AChE and what does it do?
Acetylcholinesterase
breaks down ACh to choline +acetic acid
What is the sympathetic postganglionic neurotransmitter?
Norepinephrine (NE) or Noradrenaline
Where is NE synthesized?
At presynaptic postganglionic cell terminal
What is dopamine?
intermediate product in production of norepinephrine
Tyr –> dopamine –> NE
What is the role of tyrosine in the postganglionic fiber?
Precursor to NE
starting material
Tyr –> dopamine –> NE
What is epinephrine?
Adrenaline
NOT a NT in the ANS
What is epinephrine derived from?
Norepinephrine (NE)