Chapter 14 Mastering A&P

The ANS contains both sensory and motor neurons.. True False

False

The ANS stimulates smooth muscles, skeletal muscles and glands, whereas the somatic nervous system innervates skeletal muscles only. True False

False

The sympathetic and parasympathetic divisions of the ANS have the same effect on most body organ systems. True False

False

Blood "shunting" is a dangerous situation in which the vital organs shut down, causing the body to go into circulatory shock. True False

False During circulatory shock (inadequate blood flow to body tissues), or when more blood is needed to meet the increased demands of working skeletal muscles, blood vessels serving the skin and abdominal viscera strongly constrict. This blood "shunting" helps maintain circulation to vital organs and skeletal muscles.

The craniosacral division is another name for the parasympathetic division. The craniosacral division is another name for the parasympathetic division. True False

True

Which of the following does not describe the ANS? general visceral motor system involuntary nervous system a system of motor neurons that innervates smooth and cardiac muscle and glands a system of motor neurons that innervates all muscle cells

a system of motor neurons that innervates all muscle cells

What differentiates an autonomic reflex from a somatic reflex? a single sensory neuron in the sensory pathway a two-neuron motor pathway an integration center presence of a sensory receptor

a two-neuron motor pathway rationale: Visceral reflex arcs have essentially the same components as somatic reflex arcs - receptor, sensory neuron, integration center, motor neuron, and effector. A key difference is that a visceral reflex arc has two neurons in its (autonomic) motor component, whereas the somatic reflex arc has a single (somatic) motor neuron.

The two divisions of the autonomic nervous system (ANS) normally have a(n) __________ relationship. antagonistic disruptive synergistic mutualistic

antagonistic rationale: Normally, both ANS divisions are partially active. Action potentials continually fire down both sympathetic and parasympathetic axons, producing a dynamic antagonism that precisely controls visceral activity. However, one division usually predominates in given circumstances, producing an effect that is countered by the other division (resulting in opposite actions at the target organ). In a few cases the two divisions actually cooperate with each other.

the parasympathetic nervous system is more active when we are ______. at rest digesting food exercising both a and b

both a and b

Which of the following is NOT associated with the parasympathetic division of the autonomic nervous system (ANS)? emergency action resting energy conservation digesting

emergency action rationale: 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.

Because the ANS is a visceral motor system, afferent pathways are of no importance and actually are rarely found. True False

false

Control of temperature, endocrine activity, and thirst are functions associated with the ________. medulla hypothalamus thalamus cerebellum

hypothalamus

Which of the following is responsible for the overall integration of the autonomic nervous system (ANS)? frontal lobe of the cerebral cortex reticular formation brain stem hypothalamus

hypothalamus rationale: The hypothalamus stands at the top of the control hierarchy as the integrator of ANS activity.

Sympathetic division stimulation causes ________. increased blood glucose, increased GI peristalsis, and decreased heart rate and blood pressure increased blood glucose, decreased GI peristalsis, and increased heart rate and blood pressure decreased blood glucose, increased GI peristalsis, and decreased heart rate and blood pressure decreased blood glucose, increased GI peristalsis, and increased heart rate and blood pressure

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

preganglionic axons are ________. heavily myelinated lightly myelinated nonmyelinated lightly myelinated and nonmyelinated

lightly myelinated

Which component of the ANS is characterized by ganglia located in or near effector organs? sympathetic division somatic division parasympathetic division

parasympathetic

The "resting and digesting" division of the autonomic nervous system is the ________. somatic division peripheral nervous system sympathetic division parasympathetic division

parasympathetic division

Which division of the nervous system has short preganglionic neurons? somatic sensory somatic motor sympathetic parasympathetic

sympathetic rationale: The sympathetic division has short preganglionic fibers and long postganglionic fibers. The parasympathetic division has long preganglionic fibers and short postganglionic fibers. The somatic division has a single lower motor fiber (no preganglionic or postganglionic fibers).

In general, sympathetic innervation of visceral organs inhibits the activity of these organs. This is logical because, sympathetic input primes the body to enter a resting state sympathetic input is always inhibitory parasympathetic innervation is lacking from this area sympathetic activity primes the body for physical activity and temporarily shuts down noncritical body activities

sympathetic activity primes the body for physical activity and temporarily shuts down noncritical body activities

Preparing the body for the "fight-or-flight" response is the role of the ________. cerebrum parasympathetic nervous system sympathetic nervous system somatic nervous system

sympathetic nervous system

Acetylcholine is the substance released by the axonal endings of the somatic efferent fibers and by the parasympathetic nerve fiber endings. True False

true

The autonomic nervous system may cause activation or inhibition, depending on the division that is active and the target that is affected. True False

true

The sympathetic division is also called the "thoracolumbar division" of the autonomic nervous system. True False

true rationale: The sympathetic division is also called the "thoracolumbar division" of the autonomic nervous system because the thoracic and upper lumbar spinal segments (T1 through L2) contain the cell bodies of all preganglionic sympathetic neurons.

Which of the following sets of conditions accurately describes the anatomy of the parasympathetic nervous system? • Thoracolumbar origin; long preganglionic fibers; ganglia in visceral effector organs • Craniosacral origin; short preganglionic fibers; ganglia in visceral effector organs • Craniosacral origin; long preganglionic fibers; ganglia in visceral effector organs • Thoracolumbar origin; short preganglionic fibers; ganglia close to the spinal cord

Craniosacral origin; long preganglionic fibers; ganglia in visceral effector organs

Conduction through the autonomic efferent chain is faster than conduction in the somatic motor system. True False

False rationale: Preganglionic axons are thin, lightly myelinated fibers, and postganglionic axons are even thinner and nonmyelinated. Consequently, conduction through the autonomic efferent chain is slower than conduction in the somatic motor system (which uses thick, heavily myelinated fibers).

Which of the following best demonstrates an example of cooperation of the parasympathetic and sympathetic nervous systems? Parasympathetic stimulation causes vasodilation of blood vessels in the penis, leading to erection; sympathetic stimulation then causes ejaculation. Sympathetic stimulation causes vasodilation of blood vessels in the penis, leading to erection; parasympathetic stimulation then causes ejaculation. Parasympathetic stimulation causes copious sweating; sympathetic stimulation causes epidermal pores to dilate. Sympathetic stimulation causes vasodilation of blood vessels in the clitoris, leading to erection; parasympathetic stimulation then causes reflex contractions of the vagina.

Parasympathetic stimulation causes vasodilation of blood vessels in the penis, leading to erection; sympathetic stimulation then causes ejaculation. rationale: The best example of cooperative autonomic effects is seen in controls of the external genitalia. Parasympathetic stimulation causes vasodilation of blood vessels in the external genitalia, and is responsible for erection of the male penis or female clitoris during sexual excitement. Sympathetic stimulation then causes the ejaculation of semen by the penis or reflex contractions of the vagina during an orgasm.

How is it possible that norepinephrine can cause vasoconstriction in one location but vasodilation in another? Sometimes norepinephrine is released by the parasympathetic nervous system, which causes relaxation. Receptor types differ in these tissues. Norepinephrine is not released by the parasympathetic nervous system. It can't: Its actions are predictable no matter the tissue.

Receptor types differ in these tissues.

Which of the following statements is true of the parasympathetic nervous system? The preganglionic fibers are shorter than the postganglionic fibers. The fibers emerge from the brain and sacral portion of the spinal cord. The ganglia lie close to the spinal cord. All of the above statements are true.

The fibers emerge from the brain and sacral portion of the spinal cord.

For which of the following activities is the parasympathetic nervous system generally responsible? fight-or-flight responses resting and digesting vigorous physical activity sweating and dilating pupils

resting and digesting rationale: The parasympathetic division, sometimes called the "rest and digest" system, keeps body energy use as low as possible, even as it directs vital "housekeeping" activities like digesting food and eliminating feces and urine.

Which of the following is NOT an autonomic nervous system (ANS) effector? skeletal muscle cardiac muscle smooth muscle glands

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

Which organ receives major input from the sympathetic, but not parasympathetic, division? heart salivary glands bladder skin

skin rationale: The smooth muscle of dermal blood vessels and arrector pili are innervated by the sympathetic, but not parasympathetic, division.

A synonym for the autonomic nervous system reflects its major function. The synonym is _________. the peripheral nervous system the central nervous system the involuntary nervous system the somatic nervous system

the involuntary nervous system