Chapter 14 - ANS Flashcards
The preganglionic neurons’ cell bodies live ___
in the CNS
describe structure of preganglionic neurons
thin, lightly myelinated
describe structure of postganglionic neurons
nonmyelinated
postganglionic cell bodies live ___
in autonomic ganglion
effector organs of autonomic nervous system
smooth muscle, glands, cardiac muscle
What releases ACh in the autonomic nervous system?
preganglionic and postganglionic axons in the parasympathetic nervous system & preganglionic axons in the sympathetic nervous system (all except postganglionic sympathetic)
What’s the NT at the effector organs in the sympathetic nervous system?
Norepinephrine
besides ganglion, what else do some sympathetic preganglionic fibers synapse to? What do they release in that exceptional case?
adrenal medulla; release hormones norepinephrine or epinephrine into blood vessels
describe dual innervation
most of the body’s abdominopelvic and thoracic organs are innervated by both parasympathetic and sympathetic fibers
discuss the differences in the fibers’ sites of origin in the parasympathetic and sympathetic divisions
parasympathetic: fibers originate in the brain or sacral spinal nerves (craniosacral)
sympathetic: fibers originate in the thoracic and lumbar spinal cord (thoracolumbar)
discuss the differences in the relative lengths of fibers in the parasympathetic and sympathetic divisions
parasympathetic: long preganglionic and short postganglionic; sympathetic: short pre and long post
discuss the differences in the locations of ganglia in the parasympathetic and sympathetic divisions
parasympathetic: ganglia in or near visceral effector organs; sympathetic: ganglia close to spinal cord
list the ganglion & functions for the oculomotor nerve III in the parasympathetic nervous system
ciliary ganglion - constrict pupil and contract ciliary body for close vision
list the ganglia & functions for the facial nerve VII in the parasympathetic nervous system
pterygopalatine & submandibular - increase nasal secretions and tear production
list the ganglion & functions for the glossopharyngeal nerve IX in the parasympathetic nervous system
otic ganglion - increase saliva
list the plexuses of the vagus nerve X in the parasympathetic nervous system and what organs they serve
cardiac plexus - slow heart rate;
pulmonary plexus - serve lungs and bronchi;
esophageal plexus - sends branches to stomach, liver, gallbladder, pancreas, small intestine, parts of lg intestine
preganglionic fibers of the vagus nerve arise from the __ and synapse in __ ganglia in walls of target organs
medulla oblongata; intramural
pelvic splanchnic nerves innervate
pelvic organs
in the sympathetic nervous system, the preganglionic cell bodies live in the ___
lateral horns of the spinal cord in T1-L2
list the structures in order in the pathways from the preganglionic sympathetic neurons to the head and thorax
lateral horn > ventral rootlets > ventral root > spinal nerve > white ramus communicans > synapse with postganglionic fiber in sympathetic ganglion (either on same level or higher/lower level) > gray ramus communicans
what happens if a preganglionic sympathetic fiber does not synapse in the sympathetic chain?
it instead passes it and goes to a splanchnic nerve to the abdomen and pelvis
name some effectors only innervated by the sympathetic nervous system
arrector pili, adrenal gland, sweat glands
what are the cells in the adrenal medulla called?
chromaffin cells, which make and secrete catecholamines norepinephrine and epinephrine
what happens when the parasympathetic/sympathetic system is dominant in the following: eye, salivary and lacrimal glands, lungs, heart, digestive organs
___ergic fibers release ACh
cholinergic fibers
___ergic fibers release NE
adrenergic fibers (most sympathetic postganglionic)
nicotinic receptors are always ___
excitatory
muscarinic receptors are ___
sometimes excitatory, sometimes inhibitory
which postganglionic neurons are muscarinic?
all parasympathetic + sweat glands of sympathetic system
when alpha 1 receptors bind to NE or Epi, we get ___
basoconstriction, constriction of visceral organs’ sphincters, dilation of pupils
alpha 2 receptors lead to ___
decreased insulin secretion, increased blood clotting
beta 1 receptors lead to ___
increased heart rate and force of contraction, release of renin, higher BP, lower urine output
beta 2 receptors lead to ___
dilation of blood vessels & bronchioles of lungs, relaxation of smooth muscle in digestive and urinary organs
beta 3 receptors lead to ___
increased lipolysis in adipose tissue
what does neostigmine do?
inhibits acetylcholinesterase, prolonging affect of ACh, administered to help with myesthenia gravis
salbutemol helps with ___
bronchodilation, because it activates beta 2 receptors, i.e. for asthma treatment (mimics norepinephrine)
anticholinergics block ___
muscarinic receptors, inhibiting parasympathetic NS, i.e. asthma, dry up respiratory membranes, inhibit saliva production, dilate pupils
sympathomimetic drugs activate ___
adrenergic receptors in order to mimic sympathetic response; treat nasal congestion, allergies
beta blockers function to ___
block beta 1 receptors in order to decrease HR and force of contraction; for conditions like hypertension, angina, migraine; all end in -olol
alpha blockers function to ___
block alpha receptors, relax smooth muscle to treat hypertension or erectile dysfunction
the anterior hypothalamus generally deals with the ___ system
parasympathetic nervous system
the posterior hypothalamus generally deals with the ___ system
sympathetic nervous system
list some things the hypothalamus controls
heart activity, blood pressure, temperature of body, water balance, endocrine activity, emotional responses (activated through limbic system signal to activate sympathetic NS)
