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