Lec 13- Autonomic and somatic nervous system Flashcards
Preganglionic neuron
originates in the brainstem or the spinal cord.
Postganglionic neuron
lies outside the central nervous system in collections of nerve cells called autonomic ganglia.
Autonomic ganglion
are clusters of neuronal cell bodies and their dendrites. They are essentially a junction between autonomic nerves originating from the central nervous system and autonomic nerves innervating their target organs in the periphery.
Sympathetic nervous system
fight or flight
Sympathetic chain ganglia/paravertebral ganglia
Most then synapse on postganlionics here.
Which form chain of interconnected ganglia paralleling spinal cord.
Adrenal medulla
is a modified sympathetic ganglion that does not give rise to postganglionic fibers.
Release 85% Epi and 15% Norepi in response to preganglionic stimulation.
Epinephrine (Epi)
adrenaline.
Parasympathetic nervous system (PNS)
rest and digest.
Terminal ganglia
located next to or within target organ.
Vagus nerve/cranial nerve X
carries most parasymp fibers.
Innervates heart, lungs, esophagus, stomach, pancreas, liver, small intetsine, and upper half of large intestine.
Cholinergic -> ACh
Parasymp postganglionics, because release acetylcholine.
Adrenergic -> NE
Most symp postganlionics release Norepi
ACh/acetylcholine
Symp and parasymp preganglionic fibers both release this.
NE/Noreoinenephrine
Most symp postganlionic fibers release this.
Agonist
Binds to the NT’s receptor and causes the same response as the NT would.
Antagonist
Binds with the receptor, preventing the NT from binding and causing a response, yet causes no response itself.
Nicotine
An agonist to nicotinic
Curare
An antagoist to nicotinic
Muscarine
An agonist to muscarinic
Atropine
An agonist to muscarinic
a1,a2,B1,B2
two major classes of adrenergic receptors for NE and Epi
Phenylephrine (PE)
Alpha receptor non-selective agonist.
Phenocybenzamine
Alpha receptor non-selective antagonist.
Isoproteronol
Beta receptor non-selective agonist.
Treats congestive heart failure.
Albuterol
B2 agonist.
Used in inhalers for bronchial dialation.
Propranolol
Beta receptor non-selective antagonist.
Decreases stimulation of heart rate via B1, but bronchial constricts asthmatics via antagonism of B2.
Atenolol
Current beta-blocker (antagonist) for angina pectoralis, which is selective for B1 receptors.
Ephedrine
general stimulant of NE release.
Amphetamines
general stimulant of NE release.
Cocaine
Prevent NE re-uptake.
Variscosites
NT released along a series of synapses.
swellings in autonomic postganglionic fibers that simultaneously release NT over a large area of an innervated organ.
Synapses en passant
Variscosities.
Multiunit requires nerve stimulation by ANS
Dual innervation
Innervation of a single organ by both branches of the ANS.
