4.2

Question 1

The ____, ____ and the ____ have the largest nuclei of cells in the post central gyrus

Answer 1

hand, foot, and face

Question 2

an area of skin innervated by cutaneous sensory nerve fibers from one spinal nerve

Answer 2

Dermatomes

Question 3

There is some ___ in the skin between fibers from

adjacent spinal nerves so it is difficult to detect a loss of sensation when only one spinal nerve is affected

Answer 3

overlap

Question 4

• distribute nerve fibers from the spinal nerves into different peripheral nerves

Answer 4

Plexuses

Question 5

area of skin innervated by cutaneous sensory

nerve fibers from a single peripheral nerve

Answer 5

Peripheral nerve fields

Question 6

• Because of the distribution of _____,

areas of cutaneous innervation can be mapped out by dermatomes and by peripheral nerve fields

Answer 6

nerve fibers in plexuses -

Question 7

dermatomes, dermatome -

Answer 7

• Injury to a single dorsal root or spinal nerve will result in a modest sensory loss because of overlap of ____ (usually the patient can report a change in sensation, but not total loss of sensation); this area would correspond to a ______

Question 8

Injury to a plexus or a peripheral nerve (which is distal to a plexus) will result in loss of sensibility in an area corresponding to a _____

Answer 8

nerve field -

Question 9

• Sensations carried by the Anterolateral pathway (a.k.a. lateral spinothalamic tract)

Answer 9

pain and temperature

Question 10

Sensations carried in the Dorsal column pathway

Answer 10

discriminative touch and joint position sense (proprioception)

Question 11

Lamina ____, ____, and ___ are primary for synapsing of pain and temperature neurons

Answer 11

1, 2, 5

Question 12

Sensation from the anterior half of the head is carried by cranial nerve _____

Answer 12

V, the trigeminal nerve

Question 13

Neurons in the dorsal horn are arranged in sheets that run parallel to the long axis of the spinal cord

Answer 13

Laminae of the dorsal horn

Question 14

The trigeminal pain and temperature pathway takes a different course through the ____ from touch and proprioception, therefore these senses must be tested separately

Answer 14

brain stem

Question 15

Sensation from the face also travels through ____ pathways separate from the sensation ascending from the rest of the body

Answer 15

brain stem

Question 16

Hemi-section of the cord causes- ipsilateral (same side) spastic paralysis and loss of position sense
- contralateral (opposite side) loss of pain and thermal sense

Answer 16

Brown-Sequard Syndrome

Question 17

• Branches of the trigeminal nerve supply three dermatomes but unlike the dermatomes of the neck and trunk, the dermatomes of the face do not overlap
  The three Dermatomes and branches are:

Answer 17

a) V1: ophthalmic nerve
b) V2: maxillary nerve
c) V3: mandibular nerve -

Question 18

a pseudounipolar neuron that conveys action potentials from a receptor into the CNS (spinal cord or brain stem)

Answer 18

First-order neuron

Question 19

a multipolar neuron that decussates and ascends within the CNS to synapse in the thalamus

Answer 19

Second-order neuron

Question 20

a multipolar neuron that ascends from the thalamus to the parietal lobe of the cerebral cortex

Answer 20

Third order neuron

Question 21

Anterolateral pathway (a.k.a. lateral spinothalamic tract) pathway

Answer 21

first order neuron
(1) Cell body: located in a dorsal root ganglion
(2) Peripheral process: travels from a pain or
temperature receptor through a peripheral nerve
3-enters the DORSAL HORN and synapses with a -second order neuron

-second order neuron
-Decussates at the same level of the spinal
cord where the cell body is located
-) Axons ascend the spinal cord in the anterior
part of the lateral white columns
(anterolateral pathway)

third order neuron 
 -) Cell body: located in one of the nuclei of the
thalamus
- Terminates on cortical neurons in the
postcentral gyrus

Question 22

Dorsal column pathway

Answer 22

First order neuron
-Cell body: located in a dorsal root ganglion
-Peripheral process: travels through a peripheral
nerve from receptors in the skin, muscles, tendons,
and joints
-Central processes pass through a DORSAL ROOT into the spinal cord, enter the ipsilateral posterior white column and ascend to nuclei in the dorsal part of the medulla (nucleus gracilis or nucleus cuneatus) where they synapse on second order neurons - Dorsal column pathway

second order neuron

• Cell body: located in either the nucleus gracilis or nucleus cuneatus in the posterior medulla
• Axon: decussates in the medulla and ascends to the thalamus

Third order 
third order neuron 
 -) Cell body: located in one of the nuclei of the
thalamus
- Terminates on cortical neurons in the
postcentral gyrus