Quiz 2: Sidman (Ch 21 & 46)

Question 1

On this section drawn in the _____ plane, draw a Betz cell axon as it courses through the white matter.

Answer 1

coronal; goes from left side to lower middle two circles

Question 2

The medical term “stroke” is commonly used for an acute loss of some neurological function because of blood vessel disease. One manifestation of the stroke resulting from the lesion diagrammed
is _____ of voluntary movement of the face, arm, and leg on the _____ side.

Answer 2

paralysis; left

Question 3

When the lesion, as diagrammed, is in the _____ _____, limb reflexes are still present but _____ use of the limb is lost.

Answer 3

internal capsule; voluntary

Question 4

Lesions of corticospinal fibers above the level of the decussation of the pyramids cause paralysis on the _____ side of the body; lesions below the decussation cause paralysis on the _____ side. “Paralysis” is the term meaning inability to _____.

Answer 4

contralateral (opposite); ipsilateral (same); move

Question 5

A lesion in this shaded area leads to paralysis of the arm and leg on the _____ side of the body. In addition, the axons of cranial nerve XII cease to function on the _____ side.

Answer 5

right (contralateral); left (ipsilateral)

Question 6

In all three lesions, there is loss of _____ movement of the left arm and _____.
The only lesion that abolishes function in cranial nerve XII as well is the one in the section through the _____.

Answer 6

voluntary; leg; medulla

Question 7

A lesion in the corona radiata that interrupts all corticospinal axons influencing the left arm and leg is much _____ in size than a lesion in the medulla with the same consequences. Shade in the affected area on the section.

Answer 7

larger

Question 8

This lesion (shaded) in the internal capsule affects efferent corticospinal fibers as well as afferent fibers coming to the _____ gyrus from cell bodies in the _____. The resulting loss is in _____ function and in the _____ class of sensory function.

Answer 8

postcentral; thalamus; motor; somesthetic

Question 9

A lesion may produce many effects if different types of axons all pass through the damaged area. On the diagram, shade in the smallest lesion that would concurrently affect voluntary motor, somesthetic sensory, and visual functions.

Answer 9

In the middle of the curve

Question 10

From the combinations of symptoms reported and signs detected by examination, the physician, knowing the kinds of axons that would have to be involved, deduces the anatomical _____ and size of the lesion.

Answer 10

location

Question 11

This patient had a stroke with occlusion of the artery supplying the corona radiata in the central part of his _____ cerebral hemisphere.

Answer 11

right

Question 12

A lesion at “A” lies _____ to the pyramidal decussation and affects voluntary control of the _____ leg. A lesion at “B” affects voluntary control of the _____ leg.

Answer 12

superior; right; left

Question 13

Since the right lower side of the face is paralyzed in a left cortical lesion, many cortico _____ fibers also must cross the midline.

Answer 13

corticonuclear

Question 14

Decussation of corticonuclear fibers is not easily demonstrated in stained sections, even though clinical data make it clear that such decussations must occur. Corticonuclear fibers must cross at many levels in groups of _____ size.

Answer 14

variable

Question 15

If the shaded area were destroyed by sudden occlusion of the artery that nourishes it, the patient would likely be unable to move the lower _____ side of the
face or the _____ arm and leg.

Answer 15

right (contralateral); right (contralateral)

Question 16

Much of our knowledge of human neuroanatomy comes from the study of neurological disease. For example, since corticospinal lesions on one side do not paralyze breathing, we conclude that nerve cells that directly innervate intercostal muscles and the diaphragm are influenced by corti-cospinal fibers of _____ sides of the brain.

Answer 16

both

Question 17

A unilateral lesion affecting corticonuclear fibers commonly has no effect on voluntary chewing, swallowing, or phonating. Also, upper facial muscles that control forehead and brow movement are spared. Presumably, the neuromuscular apparatus directly affecting these motor functions is influenced by corticonuclear fibers of _____ sides. Corticonuclear lesions that do affect these functions must be _____.

Answer 17

both; bilateral

Question 18

The movements characteristically affected in unilateral corticonuclear and corticospinal lesions are movements of the tongue (transiently affected), lower face, arm, and leg on the _____ side from the lesion. Whether or not the anatomist can demonstrate it, most of these fibers must _____.

Answer 18

contralateral; decussate

Question 19

Some afferent nerves transmit impulses from skeletal muscles and tendons to the spinal cord. Skeletal muscle has both _____ferent and _____ferent innervation. Afferent impulses arising in skeletal muscles and _____ contribute to the regulation of muscle _____.

Answer 19

afferent; efferent; tendons, tone

Question 20

Afferent impulses influencing muscle tone in the left foot are carried along lumbar spinal nerves on the _____ side. The primary neuron cell bodies lie in lumbar _____ _____ on the _____ side.

Answer 20

left; spinal ganglia; left

Question 21

The neurons drawn on the diagram convey information for the regulation of _____ _____. The afferent “message” reaches the secondary neuron from a ganglion cell neuron on the _____ side.

Answer 21

muscle tone; ipsilateral

Question 22

The primary neuron with endings in skeletal muscle may send branches that synapse directly with anterior horn cells to form the pathway for the stretch reflex. This reflex circuit is composed of only _____ neurons. Complete the afferent and efferent parts of the stretch reflex circuit on the diagram. Indicate the synapse in the anterior horn by the conventional
sign (see figure).

Answer 22

two- line coming down from top line and crossing the other, circle and line under

Question 23

The term “dorsal,” used with reference to the spinal cord of a four-legged animal, is the equivalent of the term _____ for an upright vertebrate. In the afferent pathway influencing muscle tone, the secondary neuron cell bodies lie in the _____ horn. Place an “X” on the right posterior horn. It receives the information from afferent neurons with endings in _____ and _____. Axons of the secondary neurons in this
pathway enter the _____ tracts of the cord mainly on the _____ side as the sensory endings and terminate in the _____.

Answer 23

posterior; posterior; muscles; tendons; spinocerebellar; ipsilateral; cerebellum

Question 24

Ipsilateral means same side; contralateral means opposite side. In somesthetic sensory path-ways, the axon of the secondary neuron carries the message across to the _____lateral side of the CNS. In the spinocerebellar pathway, from a given body part all the way to the cerebellum, the peripheral receptors and nerves and the secondary cell bodies and axons all lie mainly on the same or
_____lateral side.

Answer 24

contralateral; ipsilateral

Question 25

Two terms often used for the cells within the posterior horn that give rise to the spinocerebellar pathway are Clarke’s nucleus/column and the nucleus dorsalis. The cell bodies with axons entering the spinocerebellar pathway are located in the _____ horn (or _____’s nucleus or nucleus _____).

Answer 25

posterior; Clarke’s; dorsalis

Question 26

The term Clarke’s column has the virtue of emphasizing that this prominent aggregate of cells in the anteromedial part of the Clarke’s nucleus _____ horn has the three-dimensional shape of an elongated column. In transverse section, the column appears as a nucleus.

Answer 26

posterior

Question 27

The nucleus dorsalis is found at all levels of the thoracic spinal cord.
It extends superiorly into the lowest segments of the cervical cord. Inferiorly, a few large cells typical of this nucleus are found in sections through upper lumbar levels of the spinal cord. Label the sections with “L,” “C,” and “T” to indicate Clarke’s column at the lumbar, cervical, and thoracic levels, respectively.

Answer 27

C, T, T, L

Question 28

The cells of Clarke’s column receive blood primarily from the _____ spinal artery, as they are located in the posterior horn.

Answer 28

posterior

Question 29

Primary afferent neurons with endings in tendons or _____ transmit impulses across _____ to secondary neurons of the posterior horn. In order to reach these secondary neurons, which lie mainly in the _____ segments of the spinal cord, the incoming primary fibers from the lower limbs must _____scend before they terminate. Similar fibers from the arm must _____scend to C7, C8, and thoracic levels to synapse with neurons of the nucleus dorsalis.

Answer 29

muscles; synapses; thoracic; ascend; descend

Question 30

The nucleus dorsalis receives impulses transmitted by lumbar, thoracic, and lower cervical spinal nerves. Impulses influencing muscle tone in most of the arm and neck, which are destined for the cerebellum, do not pass to secondary neurons in the nucleus dorsalis. Instead, they enter the cord via upper cervical nerves and ascend to the accessory cuneate nucleus. Draw a primary afferent fiber passing from a ganglion cell at C2 and making synaptic contact with neurons in the ipsilateral accessory cuneate nucleus.

Answer 30

Fiber starts in accessory cuneate nucleus in the caudal medulla to C2

Question 31

The accessory cuneate nucleus is located lateral to the nucleus cuneatus. It is seen on one side of this section. Place an “X” on the accessory cuneate nucleus.

Answer 31

X on right inner shaded area of nucleus cuneatus

Question 32

The accessory cuneate nucleus receives blood primarily from the posterior spinal artery. Label the posterior spinal artery on the diagram.

Answer 32

Posterior spinal artery on top right

Question 33

The encircled axons emerge from cell bodies in the _____ ______ nucleus and travel to the cerebellum with analogous axons of the _____ tract.

Answer 33

accessory cuneate; spinocerebellar

Question 34

The _____ _____ nucleus relays information about tone in neck muscles just as
the _____ ______ does for trunk and limb muscles. Both nuclei send impulses mainly to the _____lateral side of the cerebellum.

Answer 34

accessory cuneate; nucleus dorsalis; ipsilateral

Question 35

The two afferent fibers in the picture are ascending to the _____. One fiber arises from a neuron in the posterior horn and transmits information arising in muscles and tendons of the trunk or the upper or lower _____. The other fiber comes from a neuron cell body in the _____ _____ nucleus and transmits information arising in muscles and tendons of the _____.

Answer 35

cerebellum; limbs; accessory cuneate; neck

Question 36

A giraffe would be expected to have a large accessory cuneate nucleus because of the large number of primary neurons projecting from receptors located in the _____ and _____ of the long neck.

Answer 36

muscles; tendons

Question 37

The more “rostral” part of the cerebellum, labeled “S,” is the _____ior part. The cerebellum lies _____ior to the brainstem.

Answer 37

superior; posterior

Question 38

The _____ side of the head is shown in this midsagittal section. The colliculi (indicated with arrows) of the midbrain are named the left and right _____ colliculi and the left and right _____ colliculi.

Answer 38

right; superior; inferior

Question 39

On the diagram, place an “S” on the superior part of the cerebellum, a “P” on the pons, an “SC” on the superior colliculi, and an “M” on the medulla.

Answer 39

From left to right, SC, P over M, and S

Question 40

Both pictures represent the brainstem, but the cerebellum is missing from the bottom picture. On the top picture, encircle the four colliculi; place a “P” on the pons. On the bottom picture, place a “C” on the cut surface of the peduncle exposed by the removal of the cerebellum.

Answer 40

Circle colliculi; P on middle of top pic; C on dark shade in middle

Question 41

Three large bundles of fibers connect the brainstem and cerebellum; they are called the pillars or peduncles. On the diagram, label the peduncle connecting the spinal cord and the lower medulla to the cerebellum.

Answer 41

Inferior cerebellar peduncle

Question 42

The pons and the cerebellar peduncles receive blood primarily from branches of the basilar artery. Label the pons on the diagram on the right.

Answer 42

Pons on left side middle

Question 43

Complete the labels on the diagram.

Answer 43

(Top to bottom) Superior cerebellar peduncle; Inferior cerebellar peduncle; Middle cerebellar peduncle

Question 44

Place an “X” on the cut surface of the inferior cerebellar peduncle.

Answer 44

On dark shade in the middle

Question 45

Most of the fibers in the spinocerebellar pathway come up from the spinal cord and reach the cerebellum via the _____ cerebellar peduncle.

Answer 45

inferior

Question 46

Place an “S” in the encircled spinocerebellar tracts on both sections. Place an “A” on the encircled acces-sory cuneate nucleus.

Answer 46

S on both sides, A in the two circles inside

Question 47

Draw a line through the sections in this picture to indicate the ascent of the right spinocere-bellar tract into the cerebellum via the inferior cerebellar peduncle. Has this tract crossed the midline? _____

Answer 47

Line starts on left and goes down through shaded side areas; No

Question 48

Place an “X” on the right accessory cuneate nucleus. The accessory cuneate nucleus is in a very convenient position to project its axons to the cerebellum. Draw an axon projecting to the cerebellum from the accessory cuneate nucleus. Information about muscle _____ reaches the _____lateral side of the cerebellum via secondary afferent neurons with cell bodies in the ______ _____ nucleus and in the _____ _____ of spinal cord gray matter.

Answer 48

X on bottom structure’s inner middle side; 2 lines from side shaded on top structure to one in the right accessory cuneate nucleus and the other to side shaded side- tone; ipsilateral; accessory cuneate; posterior horn