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57 Cards in this Set

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Ascending spinal tracts transmit what type of information to the brain?
sensory information
Normal visceral sensation is _____________ information.

A. Nociceptive
B. Interoceptive
C. Exteroceptive
D. Proprioceptive
B. Interoceptive
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
B. Exteroceptive
Where does the 1st-order neuron of an ascending spinal tract generally run?
1st-order neurons of an ascending spinal tract run from the sensory detector to the spinal cord.
Where is the cell body generally located for the 1st-order neuron of an ascending spinal tract?
Dorsal root ganglion = cell body location for the 1st-order neuron of an ascending spinal tract.

Where is the cell body generally located for the 2nd-order neuron of an ascending spinal tract?
Spinal cord gray matter = cell body location for the 2nd-order neuron of an ascending spinal tract.
Which of these ascending spinal tract neurons will decussate?

A. First order
B. Second order
C. Third order
D. None of the above.
B. In general, all second order neurons of ascending spinal tracts will decussate.
The cell body of an ascending spinal tract 3rd-order neuron is generally located where?
In the thalamus.
Some afferent pathways branch to ___________________ or participate in __________ .
reticular formation; reflex arc
What specific type of sensory information does the lemniscal system transmit?
Temperature
Pain
Light touch
Pressure sensation
lemniscal system
spinothalamic tract
spinoreticular tract
Are delta-A type fibers myelinated or unmyelinated?
Delta-A type fibers are myelinated.
Do delta-A type fibers conduct pain slowly or quickly?
Delta-A type fibers conduct sharp pain signals quickly. Fast pain is perceived about 0.1 seconds after the stimulus.
Are C-type fibers myelinated or unmyelinated?
C-type fibers are unmyelinated.
What type of pain do C-type fibers conduct?
C-type fibers conduct burning, throbbing, and aching pain slowly. They also conduct sharp pain signals quickly.
Where is the cell body generally located for the 1st-order neuron of a descending spinal tract?
Cerebral cortex = cell body location for the 1st-order neuron of a descending spinal tract.
Where is the cell body generally located for the 2nd-order neuron of a descending spinal tract?
Anterior gray column of spinal cord = cell body location for the 2nd-order neuron of a descending spinal tract.
Which descending spinal tracts are the pathways concerned with voluntary, discrete, skilled movements, especially those of the distal parts of the limbs?
corticospinal tracts
Which descending spinal tracts may facilitate or inhibit voluntary movement or reflex activity?
reticulospinal tracts
Which descending spinal tract is concerned with reflex postural movements in response to visual stimuli?
tectospinal tract
Which descending spinal tract facilitates the activity of flexor muscles and inhibits the activity of extensor or antigravity muscles?
rubrospinal tract
Which descending spinal tract is concerned with the postural activity associated with balance?
vestibulospinal tract
Injury to upper motor neurons of a corticospinal tract would cause...?
loss of voluntary movement below the lesion, but not loss of reflexes.
(-) Babinski reflex
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)
(+) Babinski reflex
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)
A (+) Babinski reflex in an adult indicates...?
abnormality of corticospinal tract upper motor neurons, because the upper motor neurons are not influencing the reflex
What is an alternate name for a corticospinal tract?
pyramidal tract
Where is the decussation of the pyramids located?
at the junction of the medulla oblongata and the spinal cord
Are the axons of the pontine reticulospinal tract crossed or uncrossed?
uncrossed
Are the axons of the medullary reticulospinal tract crossed or uncrossed?
crossed and uncrossed
Pontine reticulospinal fibers descend through...?
anterior white column
Medullary reticulospinal fibers descend through...?
lateral white column
Fibers of the corticospinal tract arise as axons of _________ cells situated in the _____ layer of the cerebral cortex.
pyramidal; fifth
Two-thirds of corticospinal fibers arise from the __________ gyrus, and one-third of the fibers arise from the ___________ gyrus.
precentral; postcentral
What percentage of corticospinal fibers decussate at the inferior border of the medulla?
80%
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.
20; anterior corticospinal tract in the anterior white column; anterior gray
Describe the path of the corticospinal tract before it leaves the brain.
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).
The corticospinal fibers that decussate at the anterior surface of the medulla descend through the spinal cord in the ___________________________ and terminate in the ______________ horn.
lateral corticospinal tract in the lateral white column; anterior gray
Branches of the corticospinal tract pass to which nuclei?
Caudate nuclei
Lentiform nuclei
Red nuclei
Olivary nuclei
Reticular formation
Reticulospinal fibers may facilitate or inhibit the activity of what type of motor neurons?
alpha and gamma
The medial longitudinal fasiculus connects the nuclei of which cranial nerves?
CN 3, 4, 6, and 8
Fibers of the tectospinal tract arise from...?
nerve cells in the superior colliculus of the midbrain.
The majority of tectospinal fibers terminate in the _____________ horn of the upper ________ spinal cord, upon ________ with interneurons.
anterior gray; cervical; synapses
Where are the red nuclei located?
in the tegmentum of the midbrain
Where do red nuclei get their input from?
motor cerebral cortex and cerebellum
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.
tectospinal; rubrospinal
Do rubrospinal fibers decussate? If so, where?
Rubrospinal fibers decussate immediately, at the level of the red nuclei in the midbrain.
Describe the path of rubrospinal fibers after they decussate.
After decussation, rubrospinal fibers descend through the pons, medulla, and lateral white column of the spinal cord. They terminate on anterior gray horn interneurons.
Rubrospinal fibers descend through which column of the spinal cord?
lateral white column
Where do rubrospinal fibers terminate (synapse)?
on anterior gray horn interneurons
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?
rubrospinal tract
Where are the nuclei for the vestibulospinal tract fibers located?
Pons and medulla
Axons of vestibular nuclei descend through which column of the spinal cord?
anterior white column
Where do vestibulospinal fibers terminate?
where they synapse upon anterior gray horn interneurons
What clinical signs would be produced by upper motor neuron lesions of corticospinal tracts?
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
What clinical signs would be produced by lesions of extrapyramidal tracts?
1. Severe paralysis
2. Spasticity or hypertonicity of the muscles
3. Exaggerated deep muscle reflexes
4. Clasp-knife reaction
The tectospinal tract receives information from where?
CN 2 (optic nerve)