Flashcards in Autonomic Nervous System (7) Deck (58)
What is different about somatic motor system neurons, compared to autonomic efferent neurons?
Somatic motor neurons send their axons directly to their target organs (skeletal muscle), whereas autonomic nerves have two efferent neurons, the first of which synapses in a ganglia which then sends out the second (postganglionic) neuron.
What kind of synapses do somatic motor neurons have? What kind of postsynaptic receptors?
Cholinergic (Ach); Nicotinic receptors (on the NMJ)
What is the other term for the sympathetic NS?
What is the other name for the parasympathetic NS?
What is the only gland that receives direct, preganglionic innervation? What division of the ANS is responsible?
Adrenal gland; Sympathetic NS
Since it is a preganglionic nerve, it has cholinergic transmission (Ach); all preganglionics do
What is the pre-ganglionic NT for the sympathetic NS?
What is the postganglionic NT for sympathetic NS? What two exceptions and what is the NT for these?
Sweat glands and erector pili muscles are exceptions, these postganglionic sympathetic fibers use Ach
What NT is used by both preganglionic and post ganglionic parasympathetic neurons?
Sympathetic discharge does what to pupils? Bronchi? HR and force of contraction? Blood vessels of skin and gut?
Increases HR and force of contraction
Constricts vessels in skin and gut
What does sympathetic discharge do to pancreas? Adrenal glands?
Release of glucagon by pancreas ( also decreases insulin secretion
Release of Epi by adrenal glands (also NE)
What does parasympathetic discharge do to pupils? Bronchi? HR and force of contraction? Gastric vessels?
Slows HR and force of contraction
Dilates gastric vessels (also stim. digestion)
What does parasympathetic discharge generally do to pancreas?
Increases release of both insulin and glucagon
Where in the spinal cord does sympathetic outflow originate? At what vertebral levels?
In the intermediolateral (lateral) horn of the spinal cord gray matter in vertebrae T1-L2.
The axons of the preganglionic sympathetic neurons exit the spinal cord via the _____ root.
Ventral (anterior) root
What structure conducts the preganglionic fibers of the sympathetic axons to the para vertebral chain ganglia?
White communicating rami (is lateral to the gray horn)
If a preganglionic sympathetic fiber synapses on a neuron within the paravertebral chain ganglia, by what structure does it leave the ganglia to send its axon back to the peripheral nerve?
Gray communicating ramus
What other two fates besides synapsing in a paravertebral ganglia may preganglionic sympathetic nerves in the ganglia have?
1. May travel rostrally or causally in the chain before synapsing on a ganglion.
2. May exit the chain to synapse in a more peripherally located prevertebral ganglion.
Which cranial nerves are involved as preganglionic parasympathetic neurons?
3, 7, 9, 10
(Occulomotor, Facial, Glossopharyngeal, Vagus)
What cranial nerve is the Edinger-Westphal nucleus associated with? What does it control?
Occulomotor n. (III); controls pupillary constriction
What peripheral ganglion does CN III's preganglionic fibers synapse in?
Where on the brain is the Edinger-Westphal nucleus found?
In the midbrain
What two cranial nerves originate from the superior and inferior salivatory nuclei? Where in brain do the nuclei originate?
Facial n. (VII) and Glossopharyngeal n. (IX); these nuclei found in the upper medulla
What glands does parasympathetic outflow via Facial n. innervate? Parasympathetic outflow via Glossopharyngeal n.?
Facial - lacrimal and salivary glands
Glossopharyngeal - parotid gland
What two nuclei are associated with the vagus? Where do they both originate in the brain? (Is same place)
1. Dorsal motor nucleus of the vagus
2. Nucleus ambiguus
Both originate in the middle medulla
What do fibers in CN X do to the bronchial tree? Intestinal blood vessels? Peristalsis? HR?
Constrict bronchial tree
Dilate intestinal blood vessels
What ganglion do preganglionic parasympathetic fibers on CN VII headed for lacrimal glands first synapse in?
What ganglion do preganglionic parasympathetic fibers on CN IX destined for parotid gland first synapse in?
What ganglion do parasympathetic preganglionics destined for salivary glands first synapse in?
In addition to the cranial outflow, which vertebral levels also have exiting preganglionic sympathetic fibers?
(Innervate descending and sigmoid colon, rectal and bladder sphincter muscles, prostate, and other genital organs)