module 10: autonomic nervous system

sympathetic chain (trunk)(sympathetic division)

-bilateral to vertebral column -longer than the region of spinal cord that it originates from superiorly and inferiorly

abdominal aortic plexuses (autonomic)

-celia plexus -superior mesenteric plexus -inferior mesenteric plexus

parasympathetic nervous system characteristics

-does not diverge extensively and has a specific and localized response -preganglionic neurons originate in the brainstem and sacral spinal cord -postganglionic neurons are short, synapsing in the ganglion located within or near target organs

somatic nervous system characterisitcs

-innervates skeletal muscle -carries voluntary motor information -does not have ganglia -contains highly myelinated neurons and conducts signals at a rapid speed -has one lower motor neuron (one neuron from the spinal cord to the effector)

sympathetic chain ganglia (sympathetic division)

-looks like beads -along the sympathetic chain trunk

Postganglionic fibers of autonomic neurons are usually A myelinated. B unmyelinated. C larger than preganglionic fibers. D located in the spinal cord.

B

Splanchnic nerves A are formed by parasympathetic postganglionic fibers. B include preganglionic fibers that go to collateral ganglia. C control sympathetic function of structures in the head. D connect one chain ganglion with another.

B

Sympathetic preganglionic fibers are characterized as being A short in length and unmyelinated. B short in length and myelinated. C long in length and myelinated. D long in length and unmyelinated.

B

Individuals with high blood pressure may be given a medication that blocks beta receptors. How would this medication help their condition?

Blocking the beta receptors on cells would decrease or prevent sympathetic stimulation of those tissues. This would result in decreased heart rate and force of contraction and relaxation of the smooth muscle in the walls; the combination would lower blood pressure.

All preganglionic autonomic fibers release____at their axon terminals, and the effects are always____ A norepinephrine; inhibitory B norepinephrine; excitatory C acetylcholine; excitatory D acetylcholine; inhibitory

C

Which of the following ganglia belong to the sympathetic division of the ANS? A otic ganglion B sphenopalatine ganglion C sympathetic chain ganglia D all of the above

C

Cutting the ventral root of the spinal nerve at L2L2 would interrupt the transmission of what type of information? A voluntary motor output B ANS motor output C sensory input D a and b

D

Preganglionic fibers of the ANS sympathetic division originate in the A cerebral cortex of the brain. B medulla oblongata. C brainstem and sacral spinal cord. D thoracic and lumbar spinal segments.

D

The neurotransmitter at all synapses and neuroeffector junctions in the parasympathetic division of the ANS is A epinephrine. B cyclic AMP. C norepinephrine. D acetylcholine.

D

The white ramus communicans A carries the postganglionic fibers to the effector organs. B arises from the dorsal root of the spinal nerves. C has fibers that do not diverge. D carries the preganglionic fibers into a nearby sympathetic chain ganglion.

D

Visceral motor neurons in the CNS A are ganglionic neurons. B are in the dorsal root ganglion. C have unmyelinated axons except in the lower thoracic region. D send axons to synapse on peripherally located ganglionic neurons.

D

Which of these does not correctly match its plexus with the organ(s) it innervates? -Hypogastric plexus - esophagus -Celiac plexus - Abdominal viscera -Pulmonary plexus - lungs -Cardiac plexus - heart

Hypogastric plexus - esophagus

Where are intramural ganglia located?

Intramural ganglia are located in the tissues of their target organs.

Why is the parasympathetic division known as the "rest-and-digest" system? -It conserves energy and promotes sedentary activities. -It produces the mobilization and use of energy reserves. -It releases norepinephrine at neuroeffector junctions. -It increases activity in cardiovascular and respiratory systems.

It conserves energy and promotes sedentary activities.

Why is the sympathetic division of the ANS known as the "fight-or-flight" system? -It produces an inhibitory effect on the target cell. -It increases tissue metabolism and alertness. -It promotes digestion by the gastrointestinal (GI) tract. -It releases acetylcholine at neuroeffector junctions.

It increases tissue metabolism and alertness.

lumbar splanchnic nerves

L1-L2

sacral splanchnic nerves

L3-S2 -all postganglionic

inferior mesenteric plexus (autonomic)

Para: usually from hypogastric plexus -hindgut Sym: splanchnic nerve path. (T5-L2) -hindgut

superior mesenteric plexus (autonomic)

Para: vagus nerve -midgut organs Sym: splanchnic nerve path. (T5-L2) -midgut

pulmonary plexus (autonomic)

Para: vagus nerve (10) -decrease respiratory rate/constrict bronchi Sym: postganglionic sympathetic path. (T1-T5) -increased respiratory rate/dilated bronchi

celiac plexus (autonomic)

Para: vagus nerve (10) -foregut organs Sym: splanchnic nerve path. (T5-L2) -foregut

Describe preganglionic fibers and neurons and postganglionic fibers and neurons.

Preganglionic fibers are short with myelinated axons; preganglionic neurons have their cell bodies in the CNS, and their axons project to ganglia in the PNS. Postganglionic fibers are long and unmyelinated; postganglionic neurons have their cell bodies in ganglia in the PNS, and their axons innervate effector cells.

Where do the preganglionic fibers of the parasympathetic division of the ANS originate?

Preganglionic fibers of the parasympathetic division of the ANS originate in either the brainstem (cranial nerves III, IX, and X) or the sacral spinal cord.

In the inferior segments of the spinal cord, in which spinal segments do the parasympathetic autonomic nuclei lie? -L4-L5 -L3-S2 -S2-S4 -T8-L5 -T7-T12

S2-S4

Describe sympathetic chain ganglia and collateral ganglia.

Sympathetic chain ganglia (paravertebral ganglia) are on both sides of the vertebral column. Neurons in these ganglia control effectors in the body wall, inside the thoracic cavity, and in the head and limbs. Collateral ganglia (prevertebral ganglia) are anterior to the vertebral column. Neurons on these ganglia innervate tissues and organs in the abdominopelvic cavity.

Why does sympathetic stimulation have such widespread effects?

Sympathetic stimulation has such widespread effects because (1) the extensive divergence of preganglionic fibers in the sympathetic division distributes sympathetic output to many different visceral organs and tissues simultaneously, and (2) the release of E and NE by the adrenal medullae affects tissues and organs throughout the body.

thoracolumbar (sympathetic division)

T1-L2

spinal nerve pathway

T1-L2 Integumentary: -arrector pilli muslces -sweat glands (sweat) -blood vessels (dialate)

postganglionic sympathetic pathway

T1-T5 cardiac, pulmonary, esophageal

Which of the following is a major difference between the autonomic nervous system (ANS) and the somatic nervous system (SNS)? -The arrangement of the neurons connecting the CNS to the effector organs is different between the ANS and the SNS. -Afferent neurons exist only in the ANS. -Afferent information in the ANS is processed in the CNS, but not in the SNS. -Efferent impulses are sent to effector organs in the SNS, but not in the ANS. -Efferent neurons exist only in the SNS.

The arrangement of the neurons connecting the CNS to the effector organs is different between the ANS and the SNS.

Name three plexuses in the abdominopelvic cavity.

The celiac plexus, the inferior mesenteric plexus, and the hypogastric plexus are three plexuses in the abdominopelvic cavity.

Where do the nerve fibers that synapse in the prevertebral ganglia originate?

The neurons that synapse in the prevertebral ganglia originate in the inferior thoracic and superior lumbar regions of the spinal cord and pass through the sympathetic chain ganglia without synapsing before reaching the prevertebral ganglia.

The sympathetic division of the ANS has ________. -norepinephrine as a transmitter substance -preganglionic neuron cell bodies in the T1-L2 regions of the spinal cord -long postganglionic axons -short preganglionic axons -All of the choices are correct.

all of the choices are correct

postganglionic axon

an axon of the neuron that extends to the organ itself (ANS)

preganglionic axon

an axon that leaves the CNS to synapse with a second motor neuron outside the CNS

If Michael experiences a frightening situation that causes the stimulation of his sympathetic nervous system, which of the following is NOT likely to occur? -an increase in smooth muscle activity along the GI tract -a feeling of energy and euphoria -mobilization of energy reserves -elevation of muscle tone

an increase in smooth muscle activity along the GI tract

referred pain

brain misinterpretations from sensory information in spinal nerves; perceive pain originating not from the organ but in a dermatome of the skin

craniosacral (parasympathetic division)

brainstem (CN 3, 7, 9, 10) and spinal segments S2-S4

superior, middle, inferior cervical ganglion

cardiac, pulmonary, esophageal

prevertebral ganglia

celiac ganglia superior mesenteric inferior mesenteric

ganglion

collection of neuron cell bodies in the peripheral nervous system

parasympathetic division

division of autonomic nervous system -cell bodies are located in brain stem (CN 3,7,9,10) and sacral region of spinal cord (S2-S4)

sympathetic divison

division of autonomic nervous system -cells bodies of pregang. located in lateral horn of from T1 to L2

somatic nervous system

division of peripheral nervous system -targets skeletal muscle -one-neuron pathway -stimulatory effect -cell body is located in ventral horn -voluntary

autonomic nervous system

division of peripheral nervous system -targets smooth muscle, cardiac muscle, and glands -two-neuron pathway -sympathetic and parasympathetic divisions -excites or inhibits

splanchnic nerves

greater thoracic lesser thoracic least thoracic lumbar sacral

The intramural ganglia of the parasympathetic division can be found __________. -along the abdominal aorta -in the thoracic spinal region -in the tissue of the target organs -in any of the listed locations

in the tissue of the target organs

vagus nerve (parasympathetic division)

innervates majority of thoracic and abdominal cavity

dual innervation

innervation of an organ or gland by both sympathetic and parasympathetic nerve fibers

plexuses

intermixed web of axons jumping from one nerve to the next within this web

postganglionic neuron

neurons of the autonomic nervous system that form synapses directly with their target organ

norepinephrine/epinephrine (sympathetic division)

neurotransmitter released by postganglionic fibers in sympathetic division

Long, unmyelinated axons leaving the ANS ganglia are called ________ fibers.

postganglionic

gray rami communicantes

postganglionic sympathetic axons from the sympathetic trunk to the spinal nerve -unmyelinated

white rami communicantes

preganglionic sympathetic axons of T1-L2 spinal nerves -myelinated -in every pathway -act as bridges

acetylcholine

sympathetic nervous: -released by preganglionic parasympathetic: -always released by pre and post ganglion

preganglionic neuron

the first neuron in a series that transmits impulses from the CNS

Postganglionic axons of the autonomic nervous system are ________. -unmyelinated -myelinated -sometimes myelinated and sometimes unmyelinated

unmyelinated

esophageal plexus (autonomic)

Para: Vagus nerve (10) -lower esophagus smooth muscle Sym: Postganglionic path. (T1-T5) -decrease gastric motility

cardiac plexus (autonomic)

Para: Vagus nerve (10) -lower heart rate Sym: Postganglionic Sympathetic path. (T1-T5) -increase heart rate

hypogastric plexus (autonomic)

Para: from S2-S4 -lead to IM plexus or pelvic organs Sym:splanchnic nerve path. (L3-S2!!!) -pelvic organs

autonomic nervous system characteristics

-innervates smooth or cardiac muscle -carries involuntary motor information -has ganglia -contains lightly myelinated and unmyelinated neurons and conducts signals at a slower speed -has two lower motor neurons (two neurons in the pathway between the spinal cord and the effector)

sympathetic nervous system characteristics

-shows extensive divergence and can have a widespread, coordinated response -preganglionic neurons originate in the thoracic and upper lumbar spinal cord -preganglionic neurons are short, synapsing in the ganglion located near the vertebral column

pathways (sympathetic)

-spinal nerve pathway -postganglionic sympathetic pathway -splanchnic nerve pathway -adrenal medulla pathway

Match numbered item with letter 1 preganglionic 2 thoracolumbar 3 parasympathetic 4 prevertebral 5 paravertebral 6 acetylcholine 7 epinephrine 8 sympathetic 9 splanchnic 10 crisis A all preganglionic fibers B preganglionic fibers to collateral ganglia C first neuron D collateral ganglia E adrenal medulla F sympathetic activation G sympathetic division H terminal ganglia I sympathetic chain ganglia J long postganglionic fiber

1 C 2 G 3 H 4 D 5 I 6 A 7 E 8 J 9 B 10 F

Name the neurotransmitter released by most postganglionic sympathetic fibers.

Norepinephrine is the neurotransmitter released by most postganglionic sympathetic fibers.

lesser thoracic splanchnic nerves

T10-T11

least thoracic splanchnic nerve

T12 Goes to either SM gang or IM gang

pelvic splanchnic nerves (parasympathetic division)

T5-L2 -foregut, midgut, hindgut

splanchnic nerve pathway

T5-L2 foregut, midgut, hindgut, pelvic organs

greater thoracic splanchnic nerves

T5-T9

adrenal medulla pathway

T8-T12 adrenal medulla: -epinephrine/norepinephrine -no post ganglionic nuerons

What happens when an organ receives neural information from both sympathetic and parasympathetic divisions? -The actions of each division are usually antagonistic to the other. -Each division will attempt to block the reception of information in the tissue from the other division. -The neurons of each division will travel through the same ganglia. -The actions of the divisions work together to produce exaggerated changes in organ functions.

The actions of each division are usually antagonistic to the other.

Most sympathetic postganglionic fibers release which neurotransmitter at neuroeffector junctions? -acetylcholine -serotonin -dopamine -norepinephrine -cholecystokinin

norepinephrine

The above plexuses carry: -somatic fibers only. -parasympathetic, somatic, and sympathetic fibers. -parasympathetic and sympathetic fibers. -sympathetic fibers only. -somatic and parasympathetic fibers. -parasympathetic fibers only.

parasympathetic and sympathetic fibers.