Peripheral Nervous System "SNS" Flashcards
What is the predominant NT in the periphery?
ACh
ACh is the NT released from what nerves?
Somatic motor Neurons
PREganglionic sympathetic nerves
PREganglionic parasympathetic nerves
POSTganlionic parasympathetic Nerves
with one exception ______ is released from all sympathetic POSTganglionic nerves.
Norepinephrine (NE)
with one exception NE is released from all sympathetic POSTganglionic nerves what is the 1 exception?
Sweat glands
with one exception NE is released from all sympathetic POSTganglionic nerves. Sweat glands are the 1 exception. So what is released to sweat glands from sympathetic POSTganglionic nerves?
ACh
the Adrenal medulla is innervated by what?
sympathetic PREganglionic neurons.
the Adrenal medulla is innervated by sympathetic PREganglionic Neurons, hence ________ released from sympathetic preganglionic neurons elicits the release of hormones (notably EPi and NE) from the adrenal medulla
ACh
What are the 2 major subtypes of CHOLINERIC receptors?
Nicotinic
Muscarinic
Muscarinic receptors are found where?
Peripherially in tissues
Muscarinic receptors are found peripherally in tissues and innervated by ________ neurons?
Parasympathetic POSTganglionic neurons
Nicotinic receptors (nAChR) are found where?
peripherally in the motor end-plate of skeletal muscle and on cell bodies of both sympathetic and parasympathetic POSTganglionic neurons.
Nicotinic receptors (nAChR) are found peripherally in the motor end-plate of skeletal muscle and on cell bodies of both sympathetic and parasympathetic POSTganglionic neurons. they respond to what 2 things in a biphasic fashion.
ACh or ACh agonist (e.g. SCh)
In SMALL doses, ACh stimulates nicotinic receptors of the POSTganglionic sympathetic and parasympathetic neurons as well as nicotinic receptors of the skeletal muscle end plate to cause what?
Depolarization
In HIGh doses or w/ prolonged exposure, the nAChR becomes desensitized to SCh and the postsynaptic membrane becomes non-excitable; this is called what?
Phase II block
What Nerve fiber adjust skeletal muscle force and length
A-Alpha
What sensory Nerve fiber(s) are responsible for proprioception
A-Alpha
A-Beta
What Nerve fiber carry sensations of throbbing pain and temp
dC (C-fibers)
What Nerve fiber carry sensations of sharp, prickling pain, and temperature?
A-delta
Sympathetic and Parasympahetic preganglionic neurons and what fibers?
B fibers
POST ganglionic sympathetic neurons are what nerve fibers?
C-fibers (sC)
______ nerves conduct action potentials at greater velocities the ____ nerves
Myelinated
unmyelinated
Nerves with ____ diameters conduct action potentials at greater velocities than nerves w/ _____ diameters.
Larger
Smaller
Question:
what neurons conduct action potentials faster, those with larger diameters or those with smaller diameters?
Large diameters conduct action potentials at greater speeds
The sympathetic outflow is also termed what?
thoracolumbar outflow
Cardioaccelerator fibers arise from what segments?
T1-T4
The Sympathetic outflow arises from what segments?
T1-L2
or some say
T1-L3
AKA the thoracolumbar
S/S of horner’s syndrome are due to what?
stellate ganglion blockade
What are the S/S of hornet’s syndrome?
ipsilateral: Miosis Ptosis enophthalmos FLUSHING increased skin temp Anhydrosis NASAL CONGESTION
** CAPITAL S/S above are r/t CV
ALL sympathetic PREganglionic fiber pass through what?
White rami
Some but not all sympathetic POSTganglionic fibers pass through what>?
Gray Rami
PREganglionic white rami are distributed to spinal nerves arising from what segments (levels)
T1-L2
Gray Rami are distributed to what spinal nerves from the ganglia
ALL
White or Gray?? rami allow coordinated, mass discharge of the sympathetic Nervous system?
Gray