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B1 & B2 Sections A/P/P Quiz

Terms in this set (93)

What are present in white matter of the spinal cord?
Contains fiber tracts (bundles of axons)
What are present in grey matter of the spinal cord?
neurons; composes the dorsal horn and ventral horn.
What is the function of the dorsal horn?
sensory in function
What is the function of the motor horn?
motor in function
What composes the spinal nerve?
the dorsal and ventral roots come together to compose the spinal nerve.
dorsal vs. ventral
dorsal composes afferent fibers whereas the ventral horn forms based on he alpha motor neuron.
In terms of vertebral levels, how far does the spinal cord run from the skull?
L1 or L2
What is the Cauda Equina?
bundle of spinal roots that are inside the vertebral canal below L2.
Where are the C1 spinal nerves located?
They exit out of the C! vertebra
Where is the C8 spinal cord vertebrae located?
Exists below the C7 vertebra.
What is a spinal tap?
Also known as an epidural injection, it is placing a needle into the vertebral canal.
What vertebral level does a spinal tap occur at?
L4
What are the spinal cord level that encompass the upper extremity?
C5 - T1
What is the brachial plexus?
The spinal cord levels that encompass the upper extremity.
What is cervical enlargement?
Widening of the cervical vertebrae due to a higher number of motor cell bodies.
What are the spinal cord levels for the lower extremity?
L2-S4
What occurs when there is damage to the corticospinal pathways in the thoracic area?
paralysis for the lower extremities.
What occurs when there is damage to the corticospinal pathways in the cervical region?
damage to both the upper and lower extremities.
What is ipsilateral?
Means on the same side of the body's midline.
What is contralateral?
Means on the opposite side of the body's midline.
What is Decussate?
Crossing the midline.
How many neurons are involved in information retrieval in the Spinothalamic pathway and the Dorsal Column pathway?
Requires 3 neurons and is collected from a receptor from the periphery to the cortex.
What is the term that refers to the pyramidal tract in terms of its origin and target site?
Contralateral
Motor pathway, Pyramidal tract: Where does the neuron decussate?
In the Medulla and it is considered a first-order sensory.
Where does information advance from, and then go to the receptors through a series of neurons and then the brain?
Somatosensory
What is the function of the dorsal column pathway?
Discriminating touch and position sense.
What are the 5 different types of information the dorsal column pathway relays?
1. Conscious proprioception
2. Two point discrimination
3. Fine form and texture discrimination
4. Steregnosis
5. Vibration sense
What is stereognosis?
defined as discriminating touch
What do first order neurons do in the Dorsal Column pathway?
1. first order neurons are the dorsal root neuron and they convey information to the ipsilateral medulla.
2. The first order neurons will synapse on the neurons in the nucleus cuneatus OR nucleus gracilis.
3. First order neurons coming in at levels in the nucleus cuneatus
4. First order fibers coming in below the T6 level will synapse on neurons in the nucleus gracilis.
What are the bundle of axons called which synapse on nucleus cuneatus?
Fasciculus cuneatus
What are the bundles of axons called which synapse on the nucleus gracilis?
Fasciculus gracilis
Dorsal Columns = _____ + _____
fasciculus cuneatus and fasciculus gracilis
Dr. Pierce's favorite: GUESS MY LESION

Right hand lesion at the C3 loses _____from ____ and below on the _____ side.
1. conscious proprioception and discriminating touch
2. C3
3. Left
Dr. Pierce's favorite: GUESS MY LESION

Right hand lesion at the brain stem causes loss in ____ on the ___ side.
1. conscious proprioception and discriminating touch
2. left
Dr. Pierce's favorite: GUESS MY LESION

Right hand lesion at the T10 loses ___ from ____ and below on the ____ side.
1. conscious proprioception and discriminating touch
2. T10
3. Left
In the dorsal column pathway, the axons from the neurons in the nucleus cuneatus and nucleus gracilis decussates where?
medulla/medial lemniscus
For the dorsal column pathway, the second order fibers synapse where?
They typically synapse on the Ventral Posterior Lateral (VPL) nucleus of the Thalamus.
For the dorsal column pathway, the third order neurons in the VPL will send their axons to where?
Postcentral gyrus in the cortex.
What is the function of the Ventrolateral Spinothalamic pathway
Pain and temperature
What is nociception?
sensation of pain
What information does the Ventrolateral Spinothalamic pathway relays?
1. pain sensation
2. temperature sensation
3. coarse touch
In the Ventrolateral Spinothalamic pathway, where do first order fibers have their receptors?
Located in the periphery and their cell bodies in the dorsal root ganglia.
In the Ventrolateral Spinothalamic pathway, where do the first order fibers join when entering the spinal cord?
They typically enter the the dorsolateral tract.
In the Ventrolateral Spinothalamic pathway, where are the two segments in the spinal cord that the first order fibers travel up to?
Dorosolateral tract
First order fibers synapse on neurons located where?
In the Dorsal horn of the spinal cord.
In the Ventrolateral Spinothalamic pathway, where do the second order axons decussate?
They decussate in the anterior white commissure of the spinal cord.
In the Ventrolateral Spinothalamic pathway, where do the second order fibers synpase?
Thalamus
In the Ventrolateral Spinothalamic pathway, third order fibers (from the VPL) will go where?
Post central gyrus of the cortex
How does the body modulate pain?
It is processing information in the dorsal horn, which is the body's method for modulating pain transmission.
What pathways can be interrupted by actions within the dorsal horn?
Nociceptive
Why does rubbing or shaking injuries decrease pain?
This is because of gate-control mechanisms. The nocicpetive pathways are disrupted by interneurons on the dorsal horn which releases endogenous opioids.
How does endogenous opioids affect pain transmission?
inhibit the pain pathways by decreasing Ca influx ---> decreases time of action potentials through K efflux ----> decreases EPSP.
What are the two pathways that descent from the brain stem?
norepinephrine and serotonin
What are the two spinocerebellar pathways?
posterior spinocerebellar tract and the cuneo cerebellar tract
What is the function of the spinocerebellar pathways?
Carry unconscious proprioception from the body to the cerebellum.
Where does the spinocerebellar pathway carry proprioception to?
Cerebellum
Posterior spinocerebellar pathway is for what part of the body?
lower body
Cuneocerebellar tract is for what part of the body?
upper body
Where is the nucleus dorsalis found?
T1-L2
In the posterior spinocerebellar pathway, where do first order neurons synapse onto?
Nucleus Dorsalis
In the posterior spinocerebellar pathway, where do the second order fibers collect?
Ipsilateral posterior spinocerebellar pathway ----> cerebellum
In the Cuneocerebellar tract, the first order fibers coming in at C2-T4 travel to where?
Fasciculus Cuneatus - part of the dorsal columns.
In the Cuneocerebellar tract, where do first order fibers synapse onto?
Medulla
What are the second order fibers called in the Cuneocerebellar tract?
Cuneoverebellar fibers
How many neurons does the spinocerebellar pathways take to get from the extremities to the ipsilateral cerebellum?
2
What is the nucleus dorsalis?
Also referred to as Clarke's nucleus; a cell column found in the spinal cord gray matter.
Diabetes can be caused due to a dysfunction of what type of neurons which effect small blood vessels and nerves.
Proprioceptive
How many neurons does it take for the lateral corticospinal tract to get its information from the cortex to the muscle?
2
What is ataxia?
uncoordinated or unsteady movement
In the motor pathways, first order neurons are called what?
Upper Motor Neuron, found in the CNS.
In the motor pathways, second order neurons are called what?
Lower Motor Neurons, they travel to the muscle in the periphery.
What are some characteristics of upper motor neuron paralysis?
1. spasticity
2. increase tone
3. increased tendon reflexes
4. affect groups of muscles.
What is the babinski sign?
used as a test for upper motor neuron paralysis.

scratching the sole of the foot laterally causes dorsiflexion of the great toe and fanning of the other toes is a sign of upper motor neuron paralysis
Is it normal for babies to have a positive Babinski sign?
Yes, this is because their neural pathways are not fully developed.
What are some characteristics of lower motor neuron paralysis?
1. flaccid paralysis
2. lower muscle tone
3. decreased tendon reflexes.
Main control for most muscles in the system?
Corticospinal
What is the tract name for the upper motor fibers that decussated at the pyramidal decussation?
Lateral Corticospinal tract
What are three groups of the upper motor neuron in the motor pathway?
1. Pyramidal tract
2. Pyramidal decussation
3. Lateral corticospinal tract.
Dr. Pierce's favorite: GUESS MY LESION

Lesion at the upper motor neuron of the lateral corticospinal tract will cause what?
upper motor neuron paralysis and no signal to muscle from spinal cord.
What percent of the fibers in the pyramidal tract in the medulla do not decussate, but continue in the spinal cord as the ventral corticospinal tract?
10-15%
What is the function of the ventral corticospinal tract?
control postural muscles and movements.
In the ventral corticospinal tract, the upper motor neurons decussate into the spinal cord where?
the level of the lower motor neuron that is innervated.
What is Brown-Sequard Syndrome?
hemisection of the spinal cord
For Brown-Sequard Syndrome, what 3 tracts will you see signs and symptoms?
1. Lateral corticospinal tract
2. Ventrolateral spinothalamic tract
3. Dorsal columns
Lesion of lateral corticospinal tract
Upper motor neuron paralysis ipsilateral to the lesion, from the level of lesion and below.
lesion to spinothalamic tract
loss of pain and temperature sensations contralateral to lesion.
lesion to dorsal columns
Loss of conscious proprioception and discriminating touch ipsilateral to lesion.
What is the function of the vestibulospinal tract?
Helps control posture and balance by controlling extensor muscle of the trunk and proximal limbs
What is the function of the medial longitudinal fasciculus?
Help control the neck and upper back muscles.

Originates in the medial and inferior vestibular nuclei of the brainstem.
tectospinal tract function
Helps to control neck muscles to turn the head towards a stimulus.

originates from the superior colliculus of the midbrain
What is the function of the Reticulospinal tracts?
they originate in the pons and medulla of the brainstem.

They help to control the postural muscle and limb extensors.
Gamma motor neurons
They help to modulate muscle tone
The functions of Rubrospinal tract?
Serves as a supplement to the corticospinal system. They help to influence proximal limb flexors for the upper extremity.

Originates from the red nucleus of the midbrain.
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