Anatomy ANS

Which of the letters in the figure indicates the vagus nerve?

A The vagus nerve (cranial nerve X) is a component of the parasympathetic cranial outflow. It controls normal function of organs of the thoracic and upper abdominal cavities.

In which of the following structures would you expect to see afferent ganglia?

Glossopharyngeal nerve

- Secreted by preganglionic sympathetic fibers - Secreted by preganglionic parasympathetic fibers. - Secreted by postganglionic sympathetic fibers to sweat glands. - Secreted by postganglionic parasympathetic fibers.

Acetylcholine (ACh)

Which of the following is a way in which the somatic and autonomic nervous systems are similar?

Both systems share common efferent pathways. Both systems elicit the same target organ responses to their neurotransmitters. Both systems share common effectors. Both systems have ganglia in their motor pathways. None of the listed responses is correct.

Based on your understanding of the anatomy of the nervous system, what functions is Jimmy most likely to lose?

Conscious control of bladder and bowel. Without a connection between his brain and his lower spinal cord, voluntary control of bowel and bladder reflexes will be lost.

Which of the following statements is true of the group of fibers indicated by the letter D?

D indicates fibers that bypass collateral ganglia and terminate within the adrenal gland.

Organophosphate insecticides work by blocking acetylcholinesterase. Which symptom would NOT be typical of poisoning with these agents?

Dilated pupils If acetylcholinesterase is blocked, the patient should exhibit "too much" acetylcholine, the neurotransmitter that relays information to skeletal muscles and parasympathetic receptors. In other words, the parasympathetic portion of the autonomic nervous system would exert greater influence. Sympathetic activity dilates pupils, whereas parasympathetic activity constricts them.

The major anatomic difference in autonomic reflex arcs is that there are two sensory afferents.

False The major anatomical difference in autonomic reflex pathways is that there are two motor neurons, the pre- and postganglionic motor neurons.

What do the parasympathetic and sympathetic divisions have in common?

Most nerve fibers from both divisions innervate many of the same effectors. The sympathetic and parasympathetic divisions both innervate many common smooth muscles, organs, and glands.

Sympathetic responses generally are widespread because ________.

NE and epinephrine are secreted into the blood as part of the sympathetic response

Secreted by most postganglionic sympathetic fibers.

Norepinephrine (NE)

Which of the following statements is FALSE?

Sympathetic origin is craniosacral; parasympathetic is thoracolumbar.

The adrenal medulla secretes epinephrine during sympathetic stimulation. Which of the following statements describes why epinephrine would increase the sympathetic response?

The same receptors that respond to norepinephrine also respond to epinephrine, increasing the action of both. There is no separate receptor for epinephrine. It enhances the sympathetic pathways because it binds to the same receptors as norepinephrine.

Which of the following names his condition and best describes what the nurse should assess for?

This condition is called autonomic dysreflexia, and the nurse should assess for an overfilled visceral organ or a painful stimulus to his skin. The nurse should try to determine the source of the painful stimulus (such as an overfilled bladder, distended rectum, or an irritation to the skin).

Which of the following does NOT describe the ANS?

a system of motor neurons that innervates all muscle cells

What differentiates an autonomic reflex from a somatic reflex?

a two-neuron motor pathway

Which target organ is not affected by the parasympathetic division of the autonomic nervous system (ANS)?

adrenal medulla The adrenal medulla is not innervated (thus not affected) by the parasympathetic division of the ANS. Preganglionic sympathetic fibers stimulate the adrenal medulla to secrete epinephrine and norepinephrine (hormones that contribute to the overall fight-or-flight response mediated by the sympathetic division of the ANS) into the bloodstream.

Which structure or organ is innervated exclusively by sympathetic fibers?

arrector pili muscles Arrector pili muscles in the skin are innervated by sympathetic fibers but not parasympathetic fibers.

Which of the following adrenergic neurotransmitter receptors plays the major role in heart activity?

beta 1

Which of the following target organs/systems is affected by the sympathetic nervous system but is NOT affected by the parasympathetic nervous system?

cellular metabolism Preganglionic sympathetic fibers stimulate the adrenal medulla to secrete epinephrine into the bloodstream during "fight-or-flight" situations (such as exercise). In turn, epinephrine increases cellular metabolism (metabolic rate).

Which of the following is a function of the parasympathetic division?

contracts smooth muscle of the bladder wall and relaxes urethral sphincter

Drugs called beta-blockers ________.

decrease heart rate and blood pressure

Which of the following is NOT a result of parasympathetic stimulation?

dilation of the pupils

Which of the following is not associated with the parasympathetic division of the autonomic nervous system (ANS)?

emergency action The activity of the sympathetic division, often called the "fight-or-flight" system, is evident when we are excited, exercising, or find ourselves in emergency situations.

Sympathetic nerves may leave the spinal cord at which vertebra?

first thoracic

Which of the following is responsible for the overall integration of the autonomic nervous system (ANS)?

hypothalamus The hypothalamus stands at the top of the control hierarchy as the integrator of ANS activity. The limbic system communicates the hypothalamus, which is why emotions, like fear, affect the ANS. The reticular formation connects the hypothalamus to nuclei in the brainstem that cause the ANS outputs for some visceral organs as their output is regulated by the hypothalamus.

Sympathetic division stimulation causes ________.

increased blood glucose, decreased GI peristalsis, and increased heart rate and blood pressure

A mugger steals your wallet causing all of the following to happen EXCEPT ________.

increased glucose uptake to the liver from blood

Which plexus does NOT receive innervation from the vagus nerve?

inferior hypogastric plexus The inferior hypogastric plexus receives nerve fibers from the pelvic splanchnic (spinal) nerves, not the vagus (cranial) nerve. As the vagus nerves pass into the thorax, they send branches to the cardiac, pulmonary, and esophageal plexuses. In the abdominal cavity, they send fibers through the large abdominal aortic plexus.

A normal response to sympathetic nervous system activation would most likely include the __________.

inhibition of digestive system activity When in an emergency situation, digestion is not a critical body function.

Erection (vasodilation) of the penis or clitoris ________.

is primarily under parasympathetic control

Parasympathetic functions include ________.

lens accommodation for close vision

Which type of drug would be useful in dilating the pupils for an examination of the retina?

muscarinic receptor inhibitor

Autonomic nerve fibers that increase heart rate, elevate blood pressure, induce dry mouth, and increase sweating do so primarily through the secretion of __________.

norepinephrine Sympathetic fibers primarily release norepinephrine, which can have an excitatory or inhibitory effect.

All somatic motor neurons produce __________.

only acetylcholine Somatic motor neurons activate skeletal muscle fibers at neuromuscular junctions via the neurotransmitter acetylcholine.

Which of the following is mismatched?

parasympathetic postganglionic fibers; release NE

Which of the following is mismatched?

promotes urination; sympathetic

The parasympathetic ganglion that serves the lacrimal gland and nasal mucosa is the ________.

pterygopalatine ganglion

The somatic and autonomic nervous systems differ in all of the following EXCEPT ________.

regulation of activity by higher brain centers

Which is an exclusively sympathetic function?

regulation of body temperature

Which of the following appears to exert the most direct influence over autonomic functions?

reticular formation

Which of the following is not an autonomic nervous system (ANS) function?

skeletal muscle reflex The somatic nervous system stimulates skeletal muscle, whereas the ANS innervates cardiac muscle, smooth muscle, and glands.

Which target organ receives dual innervation?

small intestine

Myelination tends to be heaviest on which types of neurons?

somatic motor neurons Somatic motor neurons, those that activate skeletal muscles, are heavily myelinated.

Fibers that enter and leave the sympathetic trunks without synapsing form structures called ________.

splanchnic nerves

Preparing the body for the "fight-or-flight" response is the role of the ________.

sympathetic division

The secretions of the adrenal medulla act to supplement the effects of ________.

sympathetic stimulation

Which of the following releases the neurotransmitter norepinephrine?

terminus of a sympathetic postganglionic neuron In cases of dual innervation, release of norepinephrine at synapses within effector organs is characteristic of the sympathetic division (B). Sympathetic postganglionic neurons release acetylcholine in areas that receive only sympathetic fibers.

The synapse in pathway B has several possible locations. Which of the following is NOT a possible location?

the spinal cord

Which set of details correctly identifies a series of events in a sympathetic pathway?

thoracolumbar origin, short preganglionic fiber, ACh release at ganglion, long postganglionic fiber, NE release at effector

Autonomic motor neurons __________.

utilize a two-neuron chain to reach their effectors Autonomic neural pathways utilize two neurons, a preganglionic neuron and a postganglionic neuron, to reach their effector.

Most preganglionic fibers of the parasympathetic system arise from which nerve pair?

vagus The heart, lung, liver, gallbladder, pancreas, stomach, and intestines--virtually all of the visceral organs of the thoracic and abdominal cavities--contain ganglia innervated by nerve fibers from the vagus nerves.

The route of major parasympathetic outflow from the head is via the ________.

vagus (X) nerves

The smooth muscle of the digestive viscera is served largely by the ________.

vagus (X) nerves

The group of fibers indicated by E represents which of the following?

white rami communicantes

Where are ganglia of the parasympathetic division located?

within or near effector organs Note the location of synapses between preganglionic and ganglionic fibers on the left side of the figure that summarizes the outflow of the parasympathetic division.