Chapter 18
celiac ganglion
(prevertebral ganglia) postganglionic axons innervate stomach, spleen, liver, gallbladder, proximal duodenum, part of pancreas
superior mesenteric ganglion
(prevertebral ganglion) postganglionic axons innervate distal duodenum, part of pancreas, remainder of small intestine, proximal large intestine, kidneys, proximal part of ureters
inferior mesenteric ganglion
(prevertebral ganglion) postganglionic axons innervate the distal colon, rectum, urinary bladder, distal ureter, and most reproductive organs
If digestion is stimulated when an individual is at rest, which ANS division is likely responsible for this stimulation?
----Parasympathetic -Sympathetic
Check all that occur at visceral effectors as a result of both parasympathetic and sympathetic innervation.
----Sympathetic stimulation increases the heart rate. -Parasympathetic stimulation further increases the heart rate. ----Sympathetic innervation reduces blood flow to the GI tract. ----Parasympathetic stimulation increases activities relating to digestion of food.
Check all that are true statements regarding the anatomy and structure of the sympathetic division.
----The neuron cell bodies are located in the lateral horns of their spinal cord segments. -The preganglionic sympathetic axons remain in the spinal cord for a large distance before leaving. ----The sympathetic trunk ganglia house sympathetic ganglionic neuron cell bodies. ----The splanchnic nerves are composed of preganglionic sympathetic axons that did not synapse in a sympathetic trunk ganglion.
The anterior roots contain ____________ axons, while the posterior roots contain _____________ axons.
----motor; sensory -sensory; motor -sensory and motor; sensory -motor; sensory and motor
The _______ nuclei within the gray matter of the spinal cord send nerve impulses to skeletal muscles
----somatic motor -sensory -somatic sensory -autonomic motor -visceral sensory
As a student nervously prepares to take stage in a high school play, she feels her heart rate increase, breathing rate increase, and palms become sweaty. She is noticing effects from her ________ nervous system.
----sympathetic -parasympathetic
The sympathetic division is also called what?
---Thoracolumbar division Craniosacral division Thoracosacral division Craniolumbar division
The area of the brain that oversees all autonomic functions is the
---hypothalamus. cerebrum. cerebellum. thalamus.
Check all that are characteristics of the somatic nervous system (SNS).
-Consists of two neurons in the pathway ----Effector organs are skeletal muscle fibers ----Axons are myelinated and thick -Either excites or inhibits effector organs
Which is not an effector innervated by the autonomic nervous system?
-No exceptions; all are effectors of the autonomic nervous system ---Skeletal muscle -Glands -Smooth muscle -Cardiac muscle
Which type of innervation causes the heart rate to increase?
-Parasympathetic ----Sympathetic
The cell bodies of sensory neurons are located in the
-gray commissure. -anterior horn. -anterior funiculus. ----posterior root ganglion. -posterior funiculus.
The sympathetic trunks are located
-lateral to prevertebral ganglia. -----immediately lateral to the vertebral column. -in the craniosacral regions. -superior to the brachial plexus. -inferior to the sacral plexus.
The ANS consists of how many neurons in a pathway?
1 ---2 3 4
Which sympathetic pathway synapses in the sympathetic trunk then travels through the gray rami to synapse on target organ?
A. Adrenal medulla B. Postganglionic sympathetic C. Splanchnic nerve D. Spinal nerve---
The anterior root of the spinal nerve contains
A. Axons of both motor and sensory neurons B. Axons of sensory neurons only C. Interneurons D. Axons of motor neurons only---
Which body regions are innervated by the lumbar plexus of the spinal cord?
A. Posterior thigh B. Anterior thigh C. Medial thigh D. Anterior and Medial thigh---
Which of the following is NOT true regarding the parasympathetic division?
A. Preganglionic neurons are long B. Ganglia are found in the cranial and sacral areas C. Postganglionic neurons are long--- D. Have few branches
In the ANS the preganglionic axon enters the sympathetic trunk ganglion through the
A. Splanchnic nerve B. Gray rami C. White rami--- D. Posterior ramus
Sympathetic preganglionic axons that do not synapse in a sympathetic trunk ganglion form
A. Splanchnic nerves--- B. Autonomic plexus C. Gray rami communicantes D. intercostal nerves
Hypothalamus is the major control center for the ANS
A. True---- B. False
All of the following are true of the prevertebral ganglia except:
A. Unpaired B. Occur only in abdomen and pelvis C. Lie anterior to the vertebral column D. Joined to ventral rami by white and gray communicantes---
neuronal convergence
Axons from numerous preganglionic cells synapse on a single ganglionic cell
Match the nerve with the parasympathetic effector organs it innervates.
CN III (Oculomotor)-3 Ciliary muscles CN VII (Facial)-2 Lacrimal glands CN X (Vagus)-4 Thoracic and abdominal viscera Pelvic Splanchnic Nerves-1 Most pelvic viscera
autonomic function
CNS control within hypothalamus, brainstem, spinal cord
autonomic plexuses
Collections of sympathetic postganglionic axons and parasympathetic preganglionic axons, as well as some visceral sensory axons. These sympathetic and parasympathetic axons are close to one another, but they do not interact with one another. cardiac plexus pulmonary plexus esophogeal plexus abdominal plexus abdominal aortic plexus celiac plexus
Match the division of the autonomic nervous system with its function.
Parasympathetic division-1 Helps maintain homeostatis Sympathetic division-2 Prepares the body for stress
Match the nervous system with its function.
Somatic Nervous-1 Voluntary control of skeletal muscle Autonomic Nervous System-2 Involuntary control of visceral muscle
In which sympathetic pathway does the preganglionic neuron synapse with a ganglionic neuron, but then the postganglionic axon does not leave the trunk via a gray ramus but instead goes directly to the effector organ?
Splanchnic nerve pathway ---Postganglionic sympathetic nerve pathway Adrenal medulla pathway Descending pathway
The dual innervation on visceral effectors of both the sympathetic and parasympathetic divisions results in opposing effects.
TRUE
The parasympathetic division is also called the craniosacral division because its preganglionic neurons are housed within nuclei in the brainstem and within the lateral gray matter of the S2−S4 spinal cord segments.
TRUE
The parasympathetic division of the ANS is also called the craniosacral division.
TRUE
The two-neuron chain allows increased communication and control of the effector organ.
TRUE
Match the parasympathetic ganglia with their descriptions.
Terminal ganglia-2 Located close to the target organ Intramural ganglia-1 Located within the target organ wall
Match the rami communicantes with their description.
White rami-1 Carry preganglionic axons Gray rami-2 Carry postganglionic axons
sympathetic nervous system
activated during exercise, excitement and emergencies dilated pupils-allow more light in for clearer vision increased heart rate-more blood and oxygen available to heart and lungs nonessential functions such as digestion and motility of urinary tract are inhibited
enteric nervous system
array of neurons in the wall of the gastrointestinal tract innervates smooth muscles and glands, coordinates peristalsis includes submucosal plexus and myenteric plexus activity is stimulated by parasympathetic nervous system and inhibited by sympathetic nervous system
neuronal divergence
axons from one preganglionic cell synapse on numerous ganglionic cells
sympathetic splanchnic nerves
composed of preganglionic sympathetic axons that did not synapse in a sympathetic trunk ganglion run anteriorly from sympathetic trunk to most of viscera greater thoracic, lesser thoracic, least thoracic, lumbar, sacral typically terminate in prevertebral ganglia sympathetic postganglionic axons extend away from the ganglia and innervate many of the abdominal organs
white and gray rami
connect sympathetic trunk to each spinal nerve
myenteric plexus
controls GI tract smooth muscle activity and motility
submucosal plexus
controls secretions, absorption, mucosal folding
preganglionic neuron
first neuron in ANS pathway thin, myelinated preganglionic axon extends to second cell within an autonomic ganglion in peripheral nervous system acetylcholine excited the second neuron
prevertebral ganglia
ganglia are immediately anterior to vertebral column cluster around arteries and are named after these arteries include: celiac, superior mesenteric, and inferior mesenteric ganglia
parasympathetic division
helps conserve energy and replenish nutrient stores (rest and digest) preganglionic axons are long and postganglionic axons are short have few preganglionic axon branches ganglia are in or close to the effector craniosacral division preganglionic neurons are housed in brainstem nuclei and lateral gray matter of S2-S4 spinal chord segments ganglionic neurons are in either terminal ganglia close to target organ or intramural ganglia in wall of target organ
middle and inferior cervical ganglia
house neurons that extend postganglionic axons to thoracic viscera
sympathetic trunk ganglia
house sympathetic ganglionic neuron cell bodies one sympathetic ganglion is approximately associated with each spinal nerve have superior, middle, and inferior ganglia (only 3-not 8)
mass activation
in crisis situations simultaneous stimulation of many effectors occurs increases alertness, energy availability, heart rate, blood pressure, breathing rate and depth
dual innervation
in many effectors-receive input from both the sympathetic and parasympathetic divisions antagonistic effects-divisions can oppose each other or cooperate parasympathetic activity slows heart, sympathetic speeds it up cooperative effects-parasympathetic activity leads to erection, sympathetic leads to ejaculation
The cell bodies of the preganglionic neurons in the sympathetic division are located
in the brainstem. in the lateral gray matter of the S2−S4 spinal cord segments. ---in the lateral horns of the T1−L2 spinal cord segments. in the lateral gray matter of the S1−S2 spinal cord segments.
sympathetic trunks
located anterior to spinal nerves and immediately lateral to vertebral column string of the pearls
effects/functions of sympathetic division
may modulate activity in one effector or in many simultaneously
autonomic nervous system
motor system regulating processes below the conscious level to maintain homeostasis reflexively responds to visceral sensory inputs sends impulses to cardiac muscle, smooth muscle, and glands two neuron chain innervates involunatry muscles and glands preganglionic and ganglionic neurons two neuron chain innervates involuntary muscles and glands preganglionic, ganglionic neurons, postganglionc axons
superior cervical ganglion
postganglionic axons from cell bodies distribute to structures in the head and neck
gray rami communicantes
postganglionic sympathetic axons are carried from sympathetic trunk to spinal nerve reflects lack of myelination on axons connect to all spinal nerves including cervical, sacral, and coccygeal spinal nerves similar exit ramps on highway
splanchnic nerve pathway
preganglionic axon passes through sympathetic trunk and terminates in prevertebral ganglion postganglionic neuron extends to target organ innervates abdominal and pelvic organs travels through the sympathetic trunk synapses in prevertebral ganglion
spinal nerve pathway
preganglionic axon terminates in sympathetic trunk postganglionic neuron exits via gray ramus at same level and extends within spinal nerve to target organ innervates skin, sweat, glands synapses in sympathetic trunk postganglionic axon exits via gray rami communicantes to rejoin spinal nerve
postganglionic sympathetic nerve pathway
preganglionic axon terminates in sympathetic trunk postganglionix neuron extends directly to target organs does not leave through gray ramus innervates some head and neck structures, thoracic organs synapse in sympathetic trunk postganglionic neuron extends directly to target organ
adrenal medulla pathway
preganglionic axons innervate internal region of adrenal gland no ganglionic neuron/postganglionic axon stimulation of adrenal cells causes release of epinephrine and norepinephrine into the blood travel through the sympathetic trunk directly to adrenal medulla
white rami communicantes
preganglionic sympathetic axons of T1-L2 spinal nerves reflects myelination similar to entrance ramps on highway
sympathetic division
prepares the body for emergencies (fight or flight) increases alertness and makes nutrients available for use preganglionic axons are short and postganglionic axons are long preganglionic axons have many branches ganglia are located near the spinal chord thoracolumbar division preganglionic neuron cell bodies housed in lateral horns of first thoracic and second lumbar spinal segments more complex than parasympathetic division preganglionic axons travel with somatic motor axons to exit spinal chord via anterior roots and then T1-L2 spinal nerves ganglion close to spinal chord
parasympathetic nervous system
pupillary constriction glandular secretion increased digestive tract mobility and muscle actions leading to elimination of feces and urine
ganglionic neuron
second neuron in ANS pathway thin, unmyelinated postganglionic axon extends to effector cells they can excite or inhibit the effector with either acetylcholine or norepinephrine
autonomic tone
sustained activity in sympathetic and parasympathetic divisions sets autonomic tone that regulates target organs activity level of just one division can regulate an effector
sympathetic pathways
sympathetic preganglionic neurons originate in lateral gray horns of T1-L2 regions of the spinal chord axons travel with T1-L2 spinal nerves then leave the nerves and travel through the white rami to enter sympathetic trunk once inside the sympathetic trunk, preganglionic axons may remain at the level of entry or travel superiorly or inferiorly
somatic nervous system
works on processes that are perceived or controlled consciously sensory part involves vision, hearing, touch, proprioception motor part involves control of skeletal muscle single lower motor neuron axon extends from spinal chord to skeletal muscle fibers motor neuron large myelinated axon and releases acetylcholine to stimulate muscle single neuron system from spinal chord to skeletal muscle