Learning expectations for BIOL 131. Chapters 16, ANS
You should be able to:
• Describe the anatomy and roles of the Autonomic nervous
- Peripheral nerves contain motor/sensory nerves, motor nerves
can be somatic/innervate smooth muscle, cardiac muscle and
glands, autonomic pathways (synapsing cells along a route)
have ganglia outside spinal cord (pre/postganglionic neurons)
- Unconscious regulation, target tissues stimulated or inhibited,
2 synapses (ganglion/effector), receptor molecules
• Define ‘autonomic pathway’.
- Synapsing cells along a route
• Compare the somatic and the automatic nervous systems
including generalities and specifics.
- Somatic: motor neurons innervate skeletal muscles,
conscious/unconscious movement, one synapse (at effector),
acetylcholine, receptor molecules are nicotinic.
- Autonomic: motor neurons innervate smooth/cardiac muscles,
glands, pathways include ganglia outside spinal cord, pre/post
ganglionic neurons, unconscious regulation, target tissues
stimulated/inhibited, 2 synapses (one at ganglion/one at
effector), acetylcholine from preganglionic neurons and Ach
OR norepinephrine from postganglionic neurons. Receptor
molecules vary w/ synapse and neurotransmitter (With chain
• Describe the roles of the sympathetic and parasympathetic
nervous system and compare/contrast the two.
- Sympathetic: prepares body for exercise, affects organs via
cranial nerves/plexuses, skin: sweat glands, smooth muscle of
bv, arrector pili (skin vessels constrict, sweat glands activate,
hair stands on end>skin is cold and clammy), head: eyes
(pupils dilate), heart/lungs: bronchioles/cardiac muscles
(increased heart/respiratory rate, bronchiole dilation), organs
of abdominopelvic cavity: reduced gut movement, increased
sphincter tone, reduced reproductive/urinary organ functions.
- Parasympathetic: Prepares for rest, affects organs via cranial
nerves/plexuses. Head: salivary glands/eyes (pupils
constrict/some salivary glands activate), Vagus
nerve/plexuses: heart, lungs, esophagus (muscles relax, skin
vessels dilate>skin is warm and dry), abdominopelvic
plexuses: stomach (increased digestive activity), pelvic
splanchnic nerves/plexuses: colon, bladder (increase activity
for digestion/repair, sphincters relax/may cause bladder to
void) • Define “enteric nervous system” and state its role.
- Contains nerve plexuses within walls of digestive tract,
controls smooth muscle contractions, gland secretions,
detects changes in content of lumen
- Enteric sensory neurons detect changes in chemical
composition of contents of digestive tract/stretch of digestive
tract wall, enteric motor neurons stimulate/inhibit smooth
muscle contraction or gland secretion, enteric interneurons
connect enteric sensory/motor neurons to eachother.
• Describe in detail the anatomy of the sympathetic nervous
system and the parasympathetic system and compare/contrast
- Sympathetic: preganglionic cell bodies are in the
thorocolumbar region of the spinal cord, preganglionic axons
pass through ventral roots to lining of abdominal