Deck 48: Somatic Sensations: I General Organization, the Tactile and Position Senses

Question 1

The second neuron in the appropriate sensory pathway that connects a free nerve ending in the left thumb to the somatosensory cortex travels in which of the following?

A)Ipsilateral anterolateral column
B)Ipsilateral medial lemniscus
C)Contralateral anterolateral column
D)Contralateral medial lemniscus

Answer 1

C

Question 2

Following Questions : An individual was brought into the emergency department after a motor vehicle collision. This patient is conscious and reports no loss of consciousness during the incident. There is no physical evidence of any head trauma. However, upon examination, the following sensory deficits are noted: loss of fine touch and vibration sense in both the left arm and leg, including the hand and foot, and loss of pain and temperature sense in the right arm and leg, including the hand and foot.
A a lesion in which of the following areas of the nervous system can be ruled out in this patient?

A)Cortex
B)Brain stem
C)Peripheral nerves
D)Spinal cord

Answer 2

A

Question 3

Which of the following sensory receptors is most likely to have the highest rate of adaptation?

A)Free nerve endings
B)Meissner corpuscle
C)Merkel cell-neurite complex
D)Pacinian corpuscle
E)Ruffini ending

Answer 3

D

Question 4

The highest frequency of action potentials generated by the mechanoreceptor is most likely to occur at which of the following receptor potentials (in millivolts)?

A)-60
B)-50
C)-45
D)-40
E)-35

Question 5

Which of the following areas of the body has the greatest representation in the primary somatosensory cortex?

A)Foot
B)Face
C)Trunk
D)Forearm

Question 6

Which of the following nerve structures carries axons from the dorsal column nuclei to the thalamus?

A)Spinothalamic tract
B)Lateral lemniscus
C)Mammillothalamic tract
D)Medial lemniscus

Question 7

Following Questions : An individual was brought into the emergency department after a motor vehicle collision. This patient is conscious and reports no loss of consciousness during the incident. There is no physical evidence of any head trauma. However, upon examination, the following sensory deficits are noted: loss of fine touch and vibration sense in both the left arm and leg, including the hand and foot, and loss of pain and temperature sense in the right arm and leg, including the hand and foot.
The loss of fine touch and vibration sense involves which of the following nerve tracts in this patient?

A)Anterolateral system
B)Dorsal column system
C)Corticospinal tract
D)Medial forebrain bundle

Question 8

Which of the following is the most likely location of the injury to the nervous system in this patient?

A)Left side of cervical spinal cord
B)Right side of cervical spinal cord
C)Brain stem involving left medial lemniscus
D)Left side of lumbar spinal cord

Question 9

Following Questions :A 36-year-old man was involved in a motor vehicle collision and received an injury to the spine at the C7 level. The injury transected exactly half (anterior to posterior) of the spinal cord on the patient's right side.
During the physical examination of this patient, which of the following would describe his two-point discrimination (fine touch)?

A)Be absent on left side of body
B)Be absent on right side of body
C)Not be affected by injury
D)Be enhanced on right side

Question 10

Following Questions :A 36-year-old man was involved in a motor vehicle collision and received an injury to the spine at the C7 level. The injury transected exactly half (anterior to posterior) of the spinal cord on the patient's right side.
On which side of the patient would you expect pain and temperature sensations to be absent?

A)Left side
B)Right side
C)Neither side
D)Both sides

Question 11

A progressive rise in receptor potential (becomes less negative) of a typical mechanoreceptor is most likely to have which of the following effects on the frequency of action potentials in the axon from that mechanoreceptor?

A)Proportional decrease
B)Proportional increase
C)No change
D)Tenfold decrease
E)Tenfold increase

Question 12

Following Questions : An individual was brought into the emergency department after a motor vehicle collision. This patient is conscious and reports no loss of consciousness during the incident. There is no physical evidence of any head trauma. However, upon examination, the following sensory deficits are noted: loss of fine touch and vibration sense in both the left arm and leg, including the hand and foot, and loss of pain and temperature sense in the right arm and leg, including the hand and foot.
The loss of pain and temperature sense involves which of the following nerve tracts in this patient?

A)Corticospinal tract
B)Pontocerebellar tract
C)Dorsal column system
D)Anterolateral system

Question 13

For a sensory nerve fiber that is connected to a free nerve ending located on the left hand, the synaptic connection with the next neuron in the appropriate sensory pathway is located in which of the following?

A)Right dorsal column nucleus
B)Dorsal horn of right side of spinal cord
C)Left dorsal column nucleus
D)Dorsal horn of left side of spinal cord

Question 14

Following Questions :A 36-year-old man was involved in a motor vehicle collision and received an injury to the spine at the C7 level. The injury transected exactly half (anterior to posterior) of the spinal cord on the patient's right side.
On which side of this patient would you expect vibration sense to be absent?

A)Left side
B)Right side
C)Vibration sensation would be not be affected
D)Both sides

Question 15

For a sensory nerve fiber that is connected to a Pacinian corpuscle located on the palmer surface of the right hand, the synaptic connection with the next neuron in the appropriate sensory pathway is located in which of the following?

A)Right dorsal column nucleus
B)Left dorsal column nucleus
C)Dorsal horn of right side of spinal cord
D)Dorsal horn of left side of spinal cord

Question 16

Following Questions :A 36-year-old man was involved in a motor vehicle collision and received an injury to the spine at the C7 level. The injury transected exactly half (anterior to posterior) of the spinal cord on the patient's right side.
On which side of this patient would the position sensation (proprioception) be absent?

A)Left side
B)Right side
C)Proprioceptive sensation would not be affected
D)Both sides

Question 17

The second neuron in the appropriate sensory pathway that connects a Meissner corpuscle in the left palm to the somatosensory cortex travels in which of the following?

A)Contralateral lateral lemniscus
B)Ipsilateral anterolateral column
C)Ipsilateral medial lemniscus
D)Contralateral medial lemniscus