Chapter 15 Somatic Nervous System

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Which structure conducts action potentials directly from a sensory receptor? A) 1 B) 2 C) 3 D) 5 E) 7

A) 1

Tactile receptors composed of capsules that surround a core of collagen fibers intertwined with dendrites are called A) Ruffini corpuscles. B) lamellated corpuscles. C) tactile (Meissner) corpuscles. D) tactile discs. E) root hair plexuses.

A) Ruffini corpuscles.

Your uncle was just diagnosed with a heart attack. One of his major symptoms is left arm pain. You are not surprised because you are familiar with the phenomenon of ________ pain. A) referred B) phantom C) psychogenic D) somatic E) neurogenic

A) referred

A receptor that contains many mechanically-gated ion channels would function best as a A) tactile receptor. B) chemoreceptor. C) photoceptor D) thermoreceptor. E) light receptor.

A) tactile receptor.

Identify the structure labeled "5." A) thalamus B) cerebral cortex C) primary motor cortex D) primary sensory cortex E) autonomic ganglion

A) thalamus

The cerebellum adjusts motor activity in response to all of the following except A) touch sensations. B) visual information. C) equilibrium-related sensations. D) input from the motor cortex. E) input from proprioceptors.

A) touch sensations.

Tactile discs are to ________ as tactile corpuscles are to ________. A) Wilms; Meissner B) Merkel; Meissner C) Meissner; Merkel D) Pacinian; Merkel E) pain; pressure

B) Merkel; Meissner

The descending spinal tract that crosses to the opposite side of the body within the cord is the ________ tract. A) lateral corticospinal B) anterior corticospinal C) rubrospinal D) reticulospinal E) vestibulospinal

B) anterior corticospinal

Mechanoreceptors that respond to changes in blood pressure are called A) nociceptors. B) baroreceptors. C) chemoreceptors. D) proprioceptors. E) thermoreceptors.

B) baroreceptors.

Bladder fullness is to ________ as blood pH is to ________. A) nociceptors; thermoreceptors B) baroreceptors; chemoreceptors C) baroreceptors; nociceptors D) chemoreceptors; nociceptors E) baroreceptors; thermoreceptors

B) baroreceptors; chemoreceptors

Neurons from the fasciculus gracilis A) relay information directly to the cerebrum. B) decussate before entering the medial lemniscus. C) relay sensory information to the ipsilateral cerebral hemisphere. D) carry both crude and fine touch. E) process proprioception.

B) decussate before entering the medial lemniscus.

The afferent neuron that carries the sensation to the CNS is a ________ neuron. A) receptor B) first-order C) second-order D) third-order E) fourth-order

B) first-order

A very large, fast-adapting tactile receptor that is composed of a single dendrite enclosed by concentric layers of collagen is a A) Ruffini corpuscle. B) lamellated (Pacinian) corpuscle. C) tactile (Meissner) corpuscle. D) tactile (Merkel) disc. E) root hair plexus.

B) lamellated (Pacinian) corpuscle.

Chemoreceptors are located in all of the following except A) carotid bodies. B) aortic bodies. C) the skin. D) the organs of taste. E) the organs of smell.

C) the skin.

Sensory encoding of the perceived location of a stimulus depends on A) the frequency of action potentials. B) which labeled line is active. C) the specific location of the cortical neuron that is stimulated. D) the specific sensitivity of the peripheral receptor. E) the number of receptors stimulated.

C) the specific location of the cortical neuron that is stimulated.

Damage to the pyramidal cells of the cerebral cortex would directly affect A) perception of pain. B) sight. C) voluntary motor activity. D) hearing. E) balance.

C) voluntary motor activity.

Which of the following is true regarding the structure labeled "6"? 1. The synapse occurs between motor neurons. 2. The sensations may be filtered out. 3. The third-order neuron projects to the primary sensory cortex. 4. The third-order neuron's axon is identified. A) 1 and 4 B) 2 only C) 3 only D) 3 and 4 E) 1 and 3

D) 3 and 4

The axon labeled "2" synapses with which structure? A) 1 B) 3 C) 4 D) 5 E) 6

D) 5

Which of the following is not one of the special senses? A) hearing B) smell C) taste D) pressure E) vision

D) pressure

Each of the following is an ascending tract in the spinal cord except the A) fasciculus gracilis. B) fasciculus cuneatus. C) posterior spinocerebellar. D) reticulospinal tract. E) anterior spinothalamic.

D) reticulospinal tract.

Identify the neuron labeled "3." A) lower motor neuron B) upper motor neuron C) first-order neuron D) second-order neuron E) ganglionic neuron

D) second-order neuron

Which of the following statements is true about general senses? A) They are distributed all over the body. B) They are all mechanoreceptors. C) Receptors involved in general sensation consist of naked nerve endings. D) They are located in sense organs. E) The reception of the stimulus occurs slowly with these receptors.

A) They are distributed all over the body.

Stimulation of a neuron that terminates in the superior region of the left postcentral gyrus would produce A) a sensation in the right leg. B) a sensation in the lips. C) a muscle twitch in the right leg. D) a muscle twitch in the lips. E) both sensations and muscle twitches in the right leg.

A) a sensation in the right leg.

The pyramids on the ventral surface of the medulla oblongata are formed by fibers of the ________ tracts. A) corticospinal B) corticobulbar C) reticulospinal D) vestibulospinal E) tectospinal

A) corticospinal

Tracts of the lateral and medial pathways include all of the following except ________ tracts. A) corticospinal B) tectospinal C) rubrospinal D) reticulospinal E) vestibulospinal

A) corticospinal

Peripheral adaptation ________ the number of action potentials that reach the CNS. A) decreases B) increases C) stabilizes D) neutralizes E) amplifies

A) decreases

Which neuron delivers sensations to the CNS? A) first-order B) second-order C) third-order D) fourth-order E) sensory receptor

A) first-order

The general senses A) involve receptors that are relatively simple in structure. B) are located in specialized structures called sense organs. C) are localized to specific areas of the body. D) cannot generate action potentials. E) include taste and smell.

A) involve receptors that are relatively simple in structure.

In order for a sensation to become a perception, A) it must be received by the somatosensory cortex. B) the individual must vocalize about it. C) it must arrive over fast-conducting nerve fibers. D) the other senses must be silent. E) it must be received by the pulvinar nucleus of the thalamus.

A) it must be received by the somatosensory cortex.

The descending spinal tract that crosses to the opposite side of the body within the medulla oblongata is the ________ tract. A) lateral corticospinal B) anterior corticospinal C) rubrospinal D) reticulospinal E) vestibulospinal

A) lateral corticospinal

Identify the type of information that travels along the structure labeled "4." A) motor commands to skeletal muscles B) proprioception to the cerebral cortex C) fine touch to the cerebral cortex D) pain and crude touch sensations E) visceral motor commands to smooth muscle

A) motor commands to skeletal muscles

Endorphins can reduce perception of sensations initiated by A) nociceptors. B) mechanoreceptors. C) thermoreceptors. D) chemoreceptors. E) proprioceptors.

A) nociceptors.

Pain is to ________ as cold is to ________. A) nociceptors; thermoreceptors B) baroreceptors; chemoreceptors C) baroreceptors; nociceptors D) chemoreceptors; nociceptors E) baroreceptors; thermoreceptors

A) nociceptors; thermoreceptors

For the last few weeks, you have had an odd sensation on your upper thigh. When you touch the naked skin, it feels very strange, like you are touching your skin through layers of cloth. The surrounding area feels normal. Your doctor thinks that this may be related to spinal nerve damage related to a herniated disc. The doctor calls this change in sensation A) paresthesia. B) anesthesia. C) hypesthesia. D) synesthesia. E) kinesthesia.

A) paresthesia.

Gustatory receptors are sensitive to dissolved chemicals but insensitive to light. This is due to A) receptor specificity. B) accessory cells. C) the fact that they are interoceptors. D) receptor potentials. E) receptor speciation.

A) receptor specificity.

Identify the structure labeled "5." A) ventral root B) upper motor neuron C) first-order neuron D) second-order neuron E) dorsal root

A) ventral root

The pyramidal system provides A) voluntary control over skeletal muscles. B) voluntary control over smooth muscles. C) involuntary control over skeletal muscles. D) involuntary control over smooth muscles. E) involuntary control over cardiac muscle.

A) voluntary control over skeletal muscles.

Axons that decussate between the pyramids of the medulla oblongata belong to the ________ tracts. A) anterior corticospinal B) lateral corticospinal C) vestibulospinal D) reticulospinal E) rubrospinal

B) lateral corticospinal

Motor neurons whose cell bodies are within the spinal cord are called ________ neurons. A) upper motor B) lower motor C) preganglionic D) postganglionic E) somesthetic

B) lower motor

Which of the following is a property of thermoreceptors? A) involves specialized receptors B) monitor heat stimuli, not cold C) found in skin only D) project to reticular formation E) cold receptors found around the body in small numbers

B) monitor heat stimuli, not cold

Identify the structure labeled "1." A) primary sensory cortex B) primary motor cortex C) thalamus D) autonomic motor center E) basal nuclei

B) primary motor cortex

Action potentials from receptors involved in general sensations are interpreted in the A) premotor cortex. B) primary sensory cortex. C) general interpretive area. D) mesencephalon. E) reticular activating system.

B) primary sensory cortex.

The ________ tract provides subconscious regulation of upper limb muscle tone and movement and is part of the ________ pathway. A) tectospinal; lateral B) rubrospinal; lateral C) reticulospinal; medial D) vestibulospinal; lateral E) corticobulbar; medial

B) rubrospinal; lateral

We can localize sensations that originate in different areas of the body because A) sensory neurons carry only one modality. B) sensory neurons from specific body regions project to specific cortical regions. C) incoming sensory information is first processed by the thalamus. D) different types of sensory receptors produce action potentials of different sizes and shapes. E) of the many types of tactile receptors.

B) sensory neurons from specific body regions project to specific cortical regions.

The term general senses refers to sensitivity to all of the following, except A) temperature. B) taste. C) touch. D) vibration. E) pain.

B) taste.

The medial pathway that controls involuntary movements of head, neck, and arm position in response to sudden visual and auditory stimuli is the ________ tract. A) lateral corticospinal B) tectospinal C) rubrospinal D) reticulospinal E) vestibulospinal

B) tectospinal

Upper motor neurons of the corticospinal tract synapse with neurons in A) autonomic ganglia. B) the anterior gray horns of the spinal cord. C) the spinothalamic tract. D) the lateral gray horns of the spinal cord. E) the dorsal root ganglia.

B) the anterior gray horns of the spinal cord.

Descending (motor) pathways always involve at least ________ motor neuron(s). A) one B) two C) three D) four E) spinal

B) two

Identify the origin of the axon labeled "2." A) lower motor neuron B) upper motor neuron C) decussation neuron D) second-order neuron E) ganglionic neuron

B) upper motor neuron

_______ are receptors in the aorta that monitor the blood pressure. A) Chemoreceptors B) Nociceptors C) Baroreceptors D) Proprioceptors E) Hair cells

C) Baroreceptors

Where in the spinal cord is the structure labeled "2" located? A) anterior gray horns B) dorsal root ganglion C) anterior white column D) anterior median fissure E) posterior white column

C) anterior white column

All of the following are true of a prickling pain sensations except that they A) are carried by type A fibers. B) reach the CNS quickly. C) are interpreted by the pre-frontal cortex. D) receive conscious attention. E) often trigger somatic reflexes.

C) are interpreted by the pre-frontal cortex.

Sensations of burning or aching pain A) are carried by type A fibers. B) reach the CNS quickly. C) cause a generalized activation of the reticular formation and the thalamus. D) are well localized. E) are fast adapting.

C) cause a generalized activation of the reticular formation and the thalamus.

Identify the neuron labeled "1." A) lower motor neuron B) upper motor neuron C) first-order neuron D) second-order neuron E) ganglionic neuron

C) first-order neuron

Destruction of or damage to a lower motor neuron in the somatic nervous system produces A) the inability to localize a stimulus. B) a subconscious response to a stimulation. C) flaccid paralysis of its muscle fibers (motor unit). D) a stimulation of the innervated muscle. E) contractile paralysis of its motor unit.

C) flaccid paralysis of its muscle fibers (motor unit).

Central adaptation refers to A) the decline in activity of peripheral receptors when stimulated. B) a characteristic of phasic receptors. C) inhibition of nuclei located along a sensory pathway. D) increases in conscious perception of a sensory stimulus. E) a change in motor receptivity of a neuron.

C) inhibition of nuclei located along a sensory pathway.

What loss would result from cutting through the medial lemniscus on the right side? A) loss of pain sensation on the left side of the body B) loss of pain sensation on the right side of the body C) loss of fine touch sensation on the left side of the body D) loss of fine touch sensation on the right side of the body E) complete hemiplegia (paralysis) on the left side of the body

C) loss of fine touch sensation on the left side of the body

Damage to the tectospinal tracts would interfere with the ability to A) position the arms. B) monitor body position. C) make reflex responses of the head and neck in response to sudden movements or loud noises. D) control motor units located in the leg. E) coordinate eating and swallowing movements.

C) make reflex responses of the head and neck in response to sudden movements or loud noises.

The area of the motor cortex that is devoted to a particular region of the body is proportional to the A) size of the body area. B) distance of the body area from the brain. C) number of motor units in that region. D) number of sensory receptors in the area of the body. E) size of the nerves that serve the area of the body.

C) number of motor units in that region.

Which ascending tract carries the sensations for fine touch and vibration? A) corticobulbar B) corticospinal C) posterior (dorsal) column D) spinothalamic E) spinobulbar

C) posterior (dorsal) column

Which ascending tract carries the sensations for fine touch and vibration? A) corticobulbar B) corticospinal C) posterior (dorsal) column D) spinothalamic E) spinocerebellar

C) posterior (dorsal) column

The basal nuclei A) initiate conscious motor activity. B) activate spinal reflexes. C) provide the background patterns of movement involved in voluntary motor activities. D) exert direct control over lower motor neurons. E) act as gatekeepers, filtering out unnecessary sensorimotor activity.

C) provide the background patterns of movement involved in voluntary motor activities.

Complex motor activities such as riding a bicycle A) only require neural processing at the level of the cerebrum. B) involve little input from the brain, with practice. C) require the coordinated activity of several regions of the brain. D) are largely controlled at the level of the spinal cord. E) usually escape notice by the cerebellum.

C) require the coordinated activity of several regions of the brain.

The spinal tract that normally plays a role in the subconscious regulation of the muscles of the arms is the ________ tract. A) lateral corticospinal B) anterior corticospinal C) rubrospinal D) reticulospinal E) vestibulospinal

C) rubrospinal

The spinal tract that carries sensations from proprioceptors to the CNS is the A) fasciculus gracilis. B) fasciculus cuneatus. C) spinocerebellar. D) lateral spinothalamic. E) anterior spinothalamic.

C) spinocerebellar.

A tactile receptor composed of highly coiled dendrites that are surrounded by modified Schwann cells and a fibrous capsule is a A) lamellated corpuscle. B) Ruffini corpuscle. C) tactile (Meissner) corpuscle. D) tactile (Merkel) disc. E) root hair plexus.

C) tactile (Meissner) corpuscle.

Based on the motor homunculus, which of the following body regions has the fewest number of motor units involved? A) tongue B) face C) hands D) back trunk

D) back trunk

If a friend is talking about someone she knows who lost his special senses, you would correct her when you hear her mention ________ because it is not a special sense. A) smell B) sight C) balance D) cold E) hearing

D) cold

A brain injury to a patient results in facial paralysis. Which descending tract is most likely affected? A) corticospinal tract B) tectospinal tract C) rubrospinal tract D) corticobulbar tract E) reticulospinal tract

D) corticobulbar tract

What occurs in this neural pathway at label "3"? A) synapse B) communication between sensory and motor neurons C) amplification of motor signals D) decussation E) autonomic reflexes

D) decussation

Which of the following is/are sometimes called "prickling pain"? A) mechanical damage B) proprioception C) extremes of temperature D) fast pain E) fast and slow pain

D) fast pain

The spinal tract that relays information concerning pain and temperature to the CNS is the A) fasciculus gracilis. B) fasciculus cuneatus. C) posterior spinocerebellar. D) lateral spinothalamic. E) anterior spinothalamic.

D) lateral spinothalamic.

Axons of the corticobulbar tract terminate in the A) sensory neurons. B) somatic motor neurons in the spinal cord. C) autonomic motor neurons in the spinal cord. D) motor nuclei of cranial nerves. E) nuclei in the thalamus.

D) motor nuclei of cranial nerves.

A sensory receptor characterized peripherally as a free nerve ending which centrally uses glutamate and/or substance P as neurotransmitters would most likely be a A) chemoreceptor. B) mechanoreceptor. C) thermoreceptor. D) nociceptor. E) free receptor.

D) nociceptor.

Identify the type of information that travels along the structure labeled "2." A) motor commands to skeletal muscles B) proprioception to the cerebral cortex C) fine touch to the cerebral cortex D) pressure and touch sensations E) visceral motor commands to smooth muscle

D) pressure and touch sensations

Receptors that monitor the position of joints belong to the category called A) nociceptors. B) chemoreceptors. C) baroreceptors. D) proprioceptors. E) thermoreceptors.

D) proprioceptors.

The corticospinal system is often referred to as the A) red nucleus. B) reticular formation. C) spinothalamic tracts. D) pyramidal system. E) medullary centers.

D) pyramidal system.

A highly sensitive tactile receptor composed of dendritic processes of a single myelinated fiber that makes contact with specialized cells of the stratum germinativum (basale) is a A) lamellated corpuscle. B) tactile (Meissner) corpuscle. C) Ruffini corpuscle. D) tactile (Merkel) disc. E) root hair plexus.

D) tactile (Merkel) disc.

Thalamic neurons that project to the primary sensory cortex are ________ neurons. A) receptor B) first-order C) second-order D) third-order E) fourth-order

D) third-order

The ________ tract provides subconscious regulation of balance and muscle tone and is part of the ________ pathway. A) tectospinal; lateral B) rubrospinal; lateral C) reticulospinal; medial D) vestibulospinal; medial E) corticobulbar; medial

D) vestibulospinal; medial

We are constantly bombarded by a variety of stimuli inside and outside of our bodies. Why are we not overwhelmed by sensory information? A) We do not have receptors for most stimuli. B) Stimuli are blocked from the receptors by our immune systems. C) Most stimuli are external to our bodies and we have very few exteroceptors on the outside of the body. D) A particular receptor type can have different sensitivities to different stimuli. E) A very tiny percentage of incoming sensory information is received by the cerebral cortex.

E) A very tiny percentage of incoming sensory information is received by the cerebral cortex.

A receptor potential may A) increase neurotransmitter release. B) decrease neurotransmitter release. C) be a hyperpolarization. D) be a depolarization. E) All of the answers are correct.