Quiz 6: Sidman (Ch 48)

Question 1

Information about pain, temperature, touch, and pressure from the trunk and limbs is mediated by sensory ganglia on both sides of each spinal segment. With an arrow, indicate a spinal ganglion drawn on the diagram. No such series of segmental ganglia is found for the somesthetic senses of the head. Instead, the _____ ganglion may be conceived of as several “fused” segmental ganglia containing all of the primary neurons for the head’s _____ senses.

Answer 1

Draw to bottom two on right and label “Spinal ganglion”
trigeminal; somesthetic

Question 2

The nerve indicated by the arrow is called the trigeminal because the number of main nerve divisions peripheral to the ganglion is _____. The _____geminal ganglion is a cranial ganglion. Its cells are comparable to cells in the sensory ganglia, which lie outside the _____ _____.

Answer 2

3; trigeminal; spinal cord

Question 3

The trigeminal nerve has only one root between the ganglion and the pons. Indicate it on the diagram with an arrow. This root is the equivalent of the anterior plus posterior roots of spinal nerves. The trigeminal root contains both _____ and _____ fibers.

Answer 3

Draw arrow to large branch on top left
afferent (or sensory); efferent (or motor)

Question 4

The trigeminal root enters the region of the brainstem called the _____. Fibers mediating pain, temperature, and (to some extent) touch and pressure then turn and descend (as illustrated) through the whole length of the _____ into the upper _____ segments of spinal cord.

Answer 4

pons; medulla; cervical

Question 5

The afferent trigeminal fibers that descend from the pons through the medulla and into the cervical cord have cell bodies _____side the brainstem in a cranial _____. The descending trigeminal fibers collectively form the _____ tract of the _____. Draw an arrow to indicate the direction of impulse conduction in the fibers passing through the medulla.

Answer 5

outside; ganglion; spinal; trigeminal
Draw arrow from bottom of right side to outside right big branch into 3 directions

Question 6

The abbreviated term spinal tract of V is commonly used because the _____ is cranial nerve number _____. Although impulses in this tract pass inferiorly into the spinal cord, the impulses are destined ultimately for the thalamus and cerebral cortex. The spinal (descending) tract of V contains axons of _____ary _____ferent neurons.

Answer 6

trigeminal; V; primary; afferent

Question 7

In the spinal portions of the pain, temperature, touch, and pressure pathways, the axon of the primary neuron bifurcates upon entering the spinal cord. The branches run a short distance up and down the cord in the dorsolateral fasciculus on the margin of the _____ horn. Branches of the equivalent cranial fibers run downward in the brainstem as the _____ _____ of _____.

Answer 7

posterior; spinal tract of V

Question 8

The spinal tract of V, in the upper cervical cord and _____, is comparable in structure and function to the _____ _____ in the _____ _____.

Answer 8

medulla; dorsolateral fasciculus; spinal cord

Question 9

The encircled fibers in the cross section are afferent fibers whose cell bodies are located in _____ _____. Comparable fibers occupy the same position in all cord regions. Their central processes enter the dorsolateral fasciculus and pass up and down the cord for a segment or two.

Answer 9

spinal ganglia

Question 10

Like the short segmental fibers of the dorsolateral fasciculus in the spinal cord, the long fibers in the spinal tract of V in the medulla are _____ary axons.

Answer 10

primary

Question 11

Fibers of the spinal tract of V make synaptic contact with secondary cell bodies lying immediately medial to the fibers in the spinal _____ of V.

Answer 11

nucleus

Question 12

Note the position of the spinal nucleus of V at the C2 level. Between approximately C4 and C2, the dorsolateral fasciculus is replaced by the corresponding _____ _____ of _____, while the secondary afferent neurons of the posterior horn are replaced by the corresponding neurons of the _____ _____ of _____.

Answer 12

spinal tract of V; spinal nucleus of V

Question 13

Cells of the posterior horn of the spinal cord receive synaptic contacts from posterior root fibers entering in every spinal segment. The posterior horn is continuous with a homologous structure in the brainstem, where cells in the _____ _____ of V receive synaptic contacts from fibers of the _____ _____ of V. In the medulla and pons, the expected series of segments, sensory nerves is largely replaced by one large nerve, the _____.

Answer 13

spinal nucleus; spinal tract; trigeminal

Question 14

In the left picture, the cell bodies at “2” are _____ary sensory neurons. The fibers at “1” belong to _____ary sensory neurons. The spinal tract of V on the right picture corresponds in position and function to number _____ on the left picture. On each side of the section at C2, place an “X” on the dilated part of the posterior horn, representing the spinal nucleus of V.

Answer 14

secondary; primary; 1

Place “X” on both sides of shaded lines of right picture

Question 15

On the picture, label the circles drawn on the medulla section with a “G” and a “C” to represent the nuclei gracilis and cuneatus, and put an “N” on the spinal nucleus of V and a “T” on the spinal tract of V.

Answer 15

Top to bottom: G, C, N, and T on top right of N in lighter shaded region

Question 16

Fibers in the spinal _____ of V transmit impulses to neurons with cell bodies in the spinal _____ of V; the latter neurons are _____ary sensory neurons of the tri_____ system. They convey information about the _____ senses.

Answer 16

tract; nucleus; secondary; trigeminal; somesthetic

Question 17

On both sides of the appropriate picture, connect the dorso-lateral fasciculus and the nerve cell bodies of the posterior horn with an arrow to show the direction of impulse conduction across the synapses. Do the same for the spinal tract and spinal nucleus of V.

Answer 17

For both pictures, draw an arrow on both sides going inward in the side shaded regions

Question 18

Place an “X” on the right poste-rior horn and right spinal nucleus of the trigeminal. Label the approximate level of each section.

Answer 18

Put X on shaded line region of top right for all three pictures

Top to bottom: C3; C8; Medulla

Question 19

Nerve cell bodies in the posterior horn of the cord and spinal nucleus of V comprise virtually all of the secondary neurons in pathways for the senses of _____ and _____ and a lesser percentage of the neurons for the senses of _____ and _____.

Answer 19

pain; temperature; touch; pressure

Question 20

On both pictures, draw a fiber of the spinal tract of V all the way from the pons into the cervical cord. Indicate the direction of impulse conduction with an arrow.

Answer 20

Left picture: line going down from 3 branches out into right side and downward
(Direction: downward)

Right picture: line going from left with 3 branches into down right
(Direction: downward)

Question 21

Trigeminal components mediate _____thetic sensation for the head. Like the spinal components, the axons of secondary trigeminal neurons terminate in the _____lateral _____.

Answer 21

somesthetic; contralateral; thalamus

Question 22

The encircled cells send axons to terminate in the _____ _____. They convey information about a _____ class of senses arising on the _____ side of the face and head.

Answer 22

contralateral thalamus; somesthetic; right

Question 23

A secondary “pain” axon is drawn at C7 and ascends into the brainstem. At C2, draw a corresponding axon emerging from a cell body in the spinal nucleus of V. Both axons will terminate in the _____ on the _____ side.

Answer 23

thalamus; contralateral

Question 24

The encircled fibers collectively form the _____ _____ tract. These are crossed axons of neuron number _____ in the afferent pathway.

Answer 24

anterior; trigeminothalamic; 2

Question 25

Axons in the lateral spinothalamic tract, axons in the medial lemniscus, and axons from nerve cell bodies in the spinal nucleus of V all make their highest synaptic contacts with neurons in the _____ and convey information about various sensory modalities on the _____ side of the body. The trunk and limbs are served by the lateral _____ tracts the way the face and head are served by the anterior _____ tracts.

Answer 25

thalamus; contralateral; spinothalamic; trigeminothalamic

Question 26

The lesion indicated by the crosshatching would cause loss of pain and temperature senses in the limbs and trunks on the _____ side of the body because the lesion interrupts the lateral _____ tract as it ascends in the _____ side of the medulla. The lesion also interrupts the descending primary axons in the skunks tract of V and causes loss of pain and temperature senses on the _____ side of the face. Thus, in this fairly common lesion in the lateral medulla, the sensory loss is on one side of the face and the _____ side of the body.

Answer 26

left; spinothalamic; right; right; contralateral