Neuro Test 3: Ascending & Descending Spinal Tracts

Front 1

Ascending spinal tracts transmit what type of information to the brain?

Back 1

sensory information

Front 2

Normal visceral sensation is _____________ information.

A. Nociceptive
B. Interoceptive
C. Exteroceptive
D. Proprioceptive

Back 2

B. Interoceptive

Front 3

You accidentally swallow a toothpick and later feel it poking your colon. The type of sensory information transmitted is best described as

A. Interoreceptive
B. Exteroceptive
C. Proprioceptive

Back 3

B. Exteroceptive

Front 4

Where does the 1st-order neuron of an ascending spinal tract generally run?

Back 4

1st-order neurons of an ascending spinal tract run from the sensory detector to the spinal cord.

Front 5

Where is the cell body generally located for the 1st-order neuron of an ascending spinal tract?

Back 5

Dorsal root ganglion = cell body location for the 1st-order neuron of an ascending spinal tract.

Front 6

Where is the cell body generally located for the 2nd-order neuron of an ascending spinal tract?

Back 6

Spinal cord gray matter = cell body location for the 2nd-order neuron of an ascending spinal tract.

Front 7

Which of these ascending spinal tract neurons will decussate?

A. First order
B. Second order
C. Third order
D. None of the above.

Back 7

B. In general, all second order neurons of ascending spinal tracts will decussate.

Front 8

The cell body of an ascending spinal tract 3rd-order neuron is generally located where?

Back 8

In the thalamus.

Front 9

Some afferent pathways branch to ___________________ or participate in __________ .

Back 9

reticular formation; reflex arc

Front 10

What specific type of sensory information does the lemniscal system transmit?

Back 10

Temperature
Pain
Light touch
Pressure sensation

Front 11

lemniscal system

Back 11

spinothalamic tract
spinoreticular tract

Front 12

Are delta-A type fibers myelinated or unmyelinated?

Back 12

Delta-A type fibers are myelinated.

Front 13

Do delta-A type fibers conduct pain slowly or quickly?

Back 13

Delta-A type fibers conduct sharp pain signals quickly. Fast pain is perceived about 0.1 seconds after the stimulus.

Front 14

Are C-type fibers myelinated or unmyelinated?

Back 14

C-type fibers are unmyelinated.

Front 15

What type of pain do C-type fibers conduct?

Back 15

C-type fibers conduct burning, throbbing, and aching pain slowly. They also conduct sharp pain signals quickly.

Front 16

Where is the cell body generally located for the 1st-order neuron of a descending spinal tract?

Back 16

Cerebral cortex = cell body location for the 1st-order neuron of a descending spinal tract.

Front 17

Where is the cell body generally located for the 2nd-order neuron of a descending spinal tract?

Back 17

Anterior gray column of spinal cord = cell body location for the 2nd-order neuron of a descending spinal tract.

Front 18

Which descending spinal tracts are the pathways concerned with voluntary, discrete, skilled movements, especially those of the distal parts of the limbs?

Back 18

corticospinal tracts

Front 19

Which descending spinal tracts may facilitate or inhibit voluntary movement or reflex activity?

Back 19

reticulospinal tracts

Front 20

Which descending spinal tract is concerned with reflex postural movements in response to visual stimuli?

Back 20

tectospinal tract

Front 21

Which descending spinal tract facilitates the activity of flexor muscles and inhibits the activity of extensor or antigravity muscles?

Back 21

rubrospinal tract

Front 22

Which descending spinal tract is concerned with the postural activity associated with balance?

Back 22

vestibulospinal tract

Front 23

Injury to upper motor neurons of a corticospinal tract would cause...?

Back 23

loss of voluntary movement below the lesion, but not loss of reflexes.

Front 24

(-) Babinski reflex

Back 24

constriction of the toes in response to pulling a finger across the bottom of the foot (a normal response in adults but abnormal in infants)

Front 25

(+) Babinski reflex

Back 25

splaying of the toes in response to pulling a finger across the bottom of the foot (a normal response in infants but an abnormal response in adults)

Front 26

A (+) Babinski reflex in an adult indicates...?

Back 26

abnormality of corticospinal tract upper motor neurons, because the upper motor neurons are not influencing the reflex

Front 27

What is an alternate name for a corticospinal tract?

Back 27

pyramidal tract

Front 28

Where is the decussation of the pyramids located?

Back 28

at the junction of the medulla oblongata and the spinal cord

Front 29

Are the axons of the pontine reticulospinal tract crossed or uncrossed?

Back 29

uncrossed

Front 30

Are the axons of the medullary reticulospinal tract crossed or uncrossed?

Back 30

crossed and uncrossed

Front 31

Pontine reticulospinal fibers descend through...?

Back 31

anterior white column

Front 32

Medullary reticulospinal fibers descend through...?

Back 32

lateral white column

Front 33

Fibers of the corticospinal tract arise as axons of _________ cells situated in the _____ layer of the cerebral cortex.

Back 33

pyramidal; fifth

Front 34

Two-thirds of corticospinal fibers arise from the __________ gyrus, and one-third of the fibers arise from the ___________ gyrus.

Back 34

precentral; postcentral

Front 35

What percentage of corticospinal fibers decussate at the inferior border of the medulla?

Back 35

80%

Front 36

The __% of corticospinal fibers that do NOT decussate at the inferior border of the medulla descend in the __________ tract in the __________ column and terminate in the _____________ horn.

Back 36

20; anterior corticospinal tract in the anterior white column; anterior gray

Front 37

Describe the path of the corticospinal tract before it leaves the brain.

Back 37

Pyramidal cells descend from the cerebral cortex. Fibers descend through the corona radiata, posterior limb of the internal capsule, cerebral peduncle of the midbrain, the anterior pons, and the anterior medulla (pyramid).

Front 38

The corticospinal fibers that decussate at the anterior surface of the medulla descend through the spinal cord in the ___________________________ and terminate in the ______________ horn.

Back 38

lateral corticospinal tract in the lateral white column; anterior gray

Front 39

Branches of the corticospinal tract pass to which nuclei?

Back 39

Caudate nuclei
Lentiform nuclei
Red nuclei
Olivary nuclei
Reticular formation

Front 40

Reticulospinal fibers may facilitate or inhibit the activity of what type of motor neurons?

Back 40

alpha and gamma

Front 41

The medial longitudinal fasiculus connects the nuclei of which cranial nerves?

Back 41

CN 3, 4, 6, and 8

Front 42

Fibers of the tectospinal tract arise from...?

Back 42

nerve cells in the superior colliculus of the midbrain.

Front 43

The majority of tectospinal fibers terminate in the _____________ horn of the upper ________ spinal cord, upon ________ with interneurons.

Back 43

anterior gray; cervical; synapses

Front 44

Where are the red nuclei located?

Back 44

in the tegmentum of the midbrain

Front 45

Where do red nuclei get their input from?

Back 45

motor cerebral cortex and cerebellum

Front 46

The ___________ tract functions to maintain balance by facilitating extensors and inhibiting flexors, whereas the ___________ tract functions to maintain balance by facilitating flexors and inhibiting extensors.

Back 46

tectospinal; rubrospinal

Front 47

Do rubrospinal fibers decussate? If so, where?

Back 47

Rubrospinal fibers decussate immediately, at the level of the red nuclei in the midbrain.

Front 48

Describe the path of rubrospinal fibers after they decussate.

Back 48

After decussation, rubrospinal fibers descend through the pons, medulla, and lateral white column of the spinal cord. They terminate on anterior gray horn interneurons.

Front 49

Rubrospinal fibers descend through which column of the spinal cord?

Back 49

lateral white column

Front 50

Where do rubrospinal fibers terminate (synapse)?

Back 50

on anterior gray horn interneurons

Front 51

Which spinal tract functions as an indirect pathway by which the cerebral cortex and the cerebellum can influence the activity of the alpha and gamma motor neurons of the spinal cord?

Back 51

rubrospinal tract

Front 52

Where are the nuclei for the vestibulospinal tract fibers located?

Back 52

Pons and medulla

Front 53

Axons of vestibular nuclei descend through which column of the spinal cord?

Back 53

anterior white column

Front 54

Where do vestibulospinal fibers terminate?

Back 54

where they synapse upon anterior gray horn interneurons

Front 55

What clinical signs would be produced by upper motor neuron lesions of corticospinal tracts?

Back 55

1. Presence of the Babinski sign
2. Absence of superficial abdominal reflexes
3. Absence of cremasteric reflex
4. Loss of performance of fine skilled voluntary movements

Front 56

What clinical signs would be produced by lesions of extrapyramidal tracts?

Back 56

1. Severe paralysis
2. Spasticity or hypertonicity of the muscles
3. Exaggerated deep muscle reflexes
4. Clasp-knife reaction

Front 57

The tectospinal tract receives information from where?

Back 57

CN 2 (optic nerve)