EXSC 224 Exam 2 Questions and Correct
Answers
ANS
-visceral motor system, subconscious
-motor neurons innervate smooth & cardiac muscle and glands
-adjust ensure optimal support for body activities
Compare the somatic and autonomic nervous systems relative to effectors, efferent
pathways, and neurotransmitters released.
Somatic
-skeletal muscle
-excitatory
-group A fibers
-Ach
ANS
-cardiac & smooth muscle, glands
-two-neuron chain (preganglionic and postganglionic neuron)
-excitatory or inhibitory
-norepinephrine sympathetic and Ach parasympathetic
Lower motor neuron
Parasympathetic = 2 neurons, Ach
-myelinated preganglionic fiber: cell body ventral horn, Group B
,-unmyelinated postganglionic fiber: travels to target, Group C
Sympathetic= 2 neurons, NE
-preganglionic synapse onto post at ganglion
-preganglionic synapse onto adrenal medulla, secretes epinephrine into blood stream
1. Name the three types of effectors of the autonomic nervous system.
cardiac muscles, smooth muscles, glands
2. Which relays instructions from the CNS to muscles more quickly, the somatic nervous
system or the ANS? Explain why.
Somatic nervous system
Only one motor neuron, heavily myelinated so signals move faster
parasympathetic division (craniosacral)
promotes maintenance functions, conserves energy, rest-and-digest (digest, defecate, urinate)
-fibers originate in brain stem or sacral spinal cord
-preganglionic long, postganglionic short
-ganglia near visceral effector organs
sympathetic division (thoracolumnar)
mobilizes body systems during activity, temporarily reduces nonessential activities, fight-or-
flight, (exercise, excitement, emergency, embarrassment)
-fibers originate in thoracic and lumbar spinal cord
, -preganglionic short, postganglionic long
-ganglia close to spinal cord
Sympathetic
-direct innervation
-thermoregulation response to heat
-releases Renin from kidneys
-metabolic effects: increases metabolic rate cells and blood glucose, mobilizes fats for fuel
dual innervation
-most visceral organs have both the parasympathetic and sympathetic divisions
-Dynamic antagonism: opposite effects
For the parasympathetic division, describe the site of CNS origin, locations of ganglia, and
general fiber pathways.
-Oculomotor nerves (III): innervate smooth muscles in the eyes, accessory oculomotor nuclei in
midbrain -> ciliary ganglia in eye
-Facial nerves (VII): activate nasal glands and lacrimal glands, lacrimal nuclei of pons ->
pterygopalatine ganglia posterior to maxillae; stimulate salivary glands, superior salivary nuclei
of pons ->submandibular ganglia deep to mandibular angles
-Glossopharyngeal nerves (IX): activate parotid salivary glands, inferior salivary nuclei of
medulla -> optic ganglia inferior to foramen ovale of skull
Answers
ANS
-visceral motor system, subconscious
-motor neurons innervate smooth & cardiac muscle and glands
-adjust ensure optimal support for body activities
Compare the somatic and autonomic nervous systems relative to effectors, efferent
pathways, and neurotransmitters released.
Somatic
-skeletal muscle
-excitatory
-group A fibers
-Ach
ANS
-cardiac & smooth muscle, glands
-two-neuron chain (preganglionic and postganglionic neuron)
-excitatory or inhibitory
-norepinephrine sympathetic and Ach parasympathetic
Lower motor neuron
Parasympathetic = 2 neurons, Ach
-myelinated preganglionic fiber: cell body ventral horn, Group B
,-unmyelinated postganglionic fiber: travels to target, Group C
Sympathetic= 2 neurons, NE
-preganglionic synapse onto post at ganglion
-preganglionic synapse onto adrenal medulla, secretes epinephrine into blood stream
1. Name the three types of effectors of the autonomic nervous system.
cardiac muscles, smooth muscles, glands
2. Which relays instructions from the CNS to muscles more quickly, the somatic nervous
system or the ANS? Explain why.
Somatic nervous system
Only one motor neuron, heavily myelinated so signals move faster
parasympathetic division (craniosacral)
promotes maintenance functions, conserves energy, rest-and-digest (digest, defecate, urinate)
-fibers originate in brain stem or sacral spinal cord
-preganglionic long, postganglionic short
-ganglia near visceral effector organs
sympathetic division (thoracolumnar)
mobilizes body systems during activity, temporarily reduces nonessential activities, fight-or-
flight, (exercise, excitement, emergency, embarrassment)
-fibers originate in thoracic and lumbar spinal cord
, -preganglionic short, postganglionic long
-ganglia close to spinal cord
Sympathetic
-direct innervation
-thermoregulation response to heat
-releases Renin from kidneys
-metabolic effects: increases metabolic rate cells and blood glucose, mobilizes fats for fuel
dual innervation
-most visceral organs have both the parasympathetic and sympathetic divisions
-Dynamic antagonism: opposite effects
For the parasympathetic division, describe the site of CNS origin, locations of ganglia, and
general fiber pathways.
-Oculomotor nerves (III): innervate smooth muscles in the eyes, accessory oculomotor nuclei in
midbrain -> ciliary ganglia in eye
-Facial nerves (VII): activate nasal glands and lacrimal glands, lacrimal nuclei of pons ->
pterygopalatine ganglia posterior to maxillae; stimulate salivary glands, superior salivary nuclei
of pons ->submandibular ganglia deep to mandibular angles
-Glossopharyngeal nerves (IX): activate parotid salivary glands, inferior salivary nuclei of
medulla -> optic ganglia inferior to foramen ovale of skull
