Deck 6: Somatosensory System

Question 1

Which of the following is the general name for a bundle of axons with the same origin and a common termination?

A)Tract
B)Pathway
C)Linea
D)Lamina

Answer 1

A
Explanation: In the CNS,a bundle of axons with the same origin and a common termination is called a tract.A pathway is a series of neurons.Somatosensory pathways are often named for the origin and termination of the tract that contains the second neuron in the series.

Question 2

Spinal axons conveying a signal for conscious somatosensation from the upper limb ascend in which of the following?

A)Ventral horn
B)Fasciculus gracilis
C)Fasciculus cuneatus
D)Internal arcuate fibers
E)Medial lemniscus

Answer 2

C
Explanation: Conscious somatosensory information from peripheral receptors is conveyed to the dorsal root and ascends through the ipsilateral dorsal column.Axons from the lower limb ascend in the medial dorsal column,called the fasciculus gracilis.Axons from the upper extremity ascend in the lateral dorsal column,called the fasciculus cuneatus.

Question 3

Spinothalamic pain is:

A)Fast.
B)Throbbing.
C)Well-localized.
D)Both A and C
E)All of the above

Answer 3

D
Explanation: A common patient report of back pain secondary to lifting a heavy object consists of an initial immediate sharp sensation that indicates the location of the injury;this is called fast or spinothalamic pain.Fast pain is often followed by a dull,throbbing ache that is not well-localized.Well-localized pain is called slow or spinolimbic pain.

Question 4

Rapidly turning the eyes and head toward a painful stimulus is a function of which one of the following tracts?

A)Trigeminoreticulolimbic
B)Spinoreticular
C)Spinomesencephalic
D)Trigeminospinothalamic
E)Dorsal column medial lemniscus

Question 5

What are the four types of somatosensations?

A)Movement,touch,temperature,and pain
B)Speed,pressure,touch,and temperature
C)Pressure,pain,touch,and temperature
D)Pain,proprioception,touch,and temperature

Question 6

Which one of the following are ascending tracts by which neurons reach the midbrain,reticular formation,and limbic areas?

A)Spinoreticular
B)Spinomesencephalic
C)Spinothalamic
D)All of the above

Question 7

The anterior spinocerebellar tract transmits information from which of the following?

A)Arms and upper half of the body
B)Legs and the lower half of the body
C)Cervical spinal cord
D)Thoracolumbar spinal cord

Question 8

Activity of the medial pain system elicits which of the following types of responses?

A)Affective
B)Arousal
C)Autonomic
D)All of the above

Question 9

Stimulation of a peripheral receptor is conveyed to the cell body of a primary neuron located in which one of the following?

A)Nucleus gracilis
B)Nucleus cuneatus
C)Dorsal root ganglion
D)Fasciculus gracilis
E)Fasciculus cuneatus

Question 10

Cell bodies of second-order neurons conveying a signal for conscious proprioceptive information from the lower limb are located in which of the following?

A)Dorsal root ganglion
B)Fasciculus cuneatus
C)Somatosensory cerebral cortex
D)Nucleus gracilis
E)Medial lemniscus

Question 11

Which of the following statements is true about the homunculus for the somatosensory cortex?

A)The homunculus was developed by experimentally recording electrical potentials from cells in the somatosensory cortex during stimulation of various parts of the body.
B)The area of the homunculus that represents the foot is adjacent to the area for the hand.
C)The proportions of the homunculus are the same as the proportions of the physical body.
D)Somatotopic organization is only found in cellular organization of the somatosensory cortex.
E)The area of the homunculus that represents the torso is adjacent to the area for the face.

Question 12

Fast pain occurs before slow pain because fast pain impulses travel on which of the following?

A)Larger,unmyelinated axons
B)Smaller,unmyelinated axons
C)Larger,myelinated axons
D)Smaller,myelinated axons

Question 13

Which of the following is a function of the primary somatosensory cortex?

A)Discrimination of the texture of an object
B)Discrimination of the shape of an object
C)Stereognosis
D)Both A and B
E)A,B,and C

Question 14

The pathways for discriminative touch and conscious proprioception use a three-neuron relay.Which one of the following describes the role of the secondary neuron?

A)Conveys information from the receptors to the medulla.
B)Conveys information from the thalamus to the cerebral cortex.
C)Conveys information from the thalamus to the medulla.
D)Conveys information from the medulla to the thalamus.

Question 15

Which one of the following is the difference between discriminative touch and conscious proprioception?

A)Discriminative touch allows for the localization of touch;conscious proprioception involves the awareness of movement of body parts.
B)Conscious proprioception allows for localization of touch;discriminative touch involves the awareness of movement of body parts.
C)No difference exists;these terms are synonymous.
D)None of the above

Question 16

The ventral posterolateral (VPL)nucleus of the thalamus is the site of synapse for:

A)First-order neurons of the dorsal column/medial lemniscus system.
B)Second-order neurons with their cell bodies in the nucleus cuneatus and/or nucleus gracilis.
C)Third-order neurons with their cell bodies in the spinal nucleus of the trigeminal cranial nerve.
D)Second-order neurons with their cell bodies in the nucleus dorsalis (Clarke's nucleus).
E)Third-order neuron with their cell body the lateral cuneate nucleus.

Question 17

A lesion to which one of the following regions would result in crossed analgesia?

A)Dorsal horn of the spinal cord
B)Peripheral nerves
C)Medulla or lower pons
D)Thalamus
E)Cortex

Question 18

Temperature information is transmitted via pathways to the:

A)Reticular formation
B)Hypothalamus
C)Subcortical nuclei
D)All of the above

Question 19

Which one of the following pathways relay high-fidelity,somatotopically arranged information to the cerebellar cortex?

A)Posterior spinocerebellar pathway
B)Anterior spinocerebellar tract
C)Cuneocerebellar pathway
D)Rostral spinocerebellar tract
E)Both A and C

Question 20

Which of the following pathways brings sensory information to the brain?

A)Conscious relay
B)Divergent
C)Unconscious relay
D)All of the above