Neuromuscular Physiopathology 2 Midterm 2 Review Study Guide

What is the process where large diameter input inhibits smaller diameter pain fibers in the dorsal horn of the spinal cord?

Segmental modulation

What is an AKA for segmental modulation?

Spinal gating

What is the process where the firing of pathways coming down from the brain have an inhibitory effect on the nociceptive pathways of the spinal cord?

Suprasegmental modulation

What types of psychological factors can effect CNS circuits involved in pain modulation?

arousal, attention, and expectation

T or F: Pain modulation pathway derangements can be a cause of chronic pain

True

Where is the initial site of pain modulation?

The spinal cord

What does the gate control theory state?

The balance of activity in nocicpetive and nonnociceptive afferent fibers can modulate pain

T or F: pain results from the balance of activity in nociceptive and nonnociceptive primary afferents

True

What is the name of the branch of large diameter fibers that communicates with inhibitory interneurons?

collateral branch

What is released from the small collateral branch of large diameter fibers?

Glutamate

What is excited by glutamate released from small collateral branches of large diameter afferents?

Inhibitory interneurons

What is released by inhibitory interneurons in the segmental pain modulation pathway?

Enkephalin

What is the function of enkephalin released from inhibitory interneurons?

Inhibits the release of substance P

Where does the raphe spinal tract originate?

Raphe nucleus

What does the raphe spinal tract do?

Inhibits release of nociceptive substance P (by exciting interneurons in the dorsal grey horns)

T or F: The motor cortex communicates with the ipsilateral cerebellum and contralateral basal ganglia

False (contralateral cerebellum, ipsilateral BG)

Where does afferent input to the motor cortex from the BG relay through?

The somatic motor relay nuclei (VA and VL of the thalamus)

On what side of the body do BG lesion signs present?

Contralateral to the lesion

On what side of the body do CB (cerebellum) lesion signs present?

Ipsilateral to the lesion

T or F: While the CB and BG do influence motor function, they are NOT upper motor neurons

True

On what portion of the frontal lobe is the primary motor cortex?

Posterior portion

Where is the primary motor cortex located in the brain?

the pre central gyrus

Where is the motor association cortex located relative to the primary motor cortex?

anterior

Where is the premotor cortex located in the brain?

The lateral aspect of the frontal lobe

Where is the supplemental motor cortex located in the brain?

Medial aspect of the frontal lobe

What brodmann area is the premotor cortex located in?

6

What brodmann area is the supplemental motor cortex in?

4

What is the final site for cortical processing of motor commands?

The primary motor cortex

T or F: The primary motor cortex functions in planning of motor commands

False (it executes motor commands)

What part of the brain is involved in motor planning?

Motor association cortex

What are the components of the motor association cortex?

premotor and supplementary motor cortices

What generates programs for motor routines necessary for skilled voluntary action?

Motor association cortex

What part of the brain controls expressive language?

Broca's area

What brodmann area is Broca's area located in?

44

What part of the brain controls eye movements?

Frontal eye fields

What brodmann area are the frontal eye fields located in?

8

What is an AKA for the motor homunculus?

Somatotopic organization

Where do neurons concerned with the lower extremity have their origins along the motor cortex?

Medial aspect

Where do neurons concerned with the upper extremity have their origins along the motor cortex?

Lateral aspect

What represents the amount of cortical dedication to a particular region of the body?

The size of the body part in the homunculus

What artery supplies the medial part of the homunculus?

Anterior cerebral artery

What does infarct of the anterior cerebral artery result in?

Contralateral weakeness and UMN lesion signs in the lower extremity

What artery supplies the lateral aspect of the homunculus?

Middle cerebral artery

What does infarct of the middle cerebral artery result in?

Contralateral weakness and UMN lesion signs in the upper extremity and face (sparing the forehead)

Why is the forehead spared in the event of a MCA stroke?

The corticobulbar tract innervates both sides of the forehead

Which muscles become relatively more hypertonic in the upper extremity due to UMN lesions?

Flexor muscles

What is the internal capsule?

a densely packed neural highway in the brain

Which artery supplies the internal capsule?

Middle cerebral artery

What is the bridge between the CNS and skeletal muscles?

Lower motor neurons

What is the final common pathway for all motor influences?

Lower motor neurons

T or F: UMN lesion signs indicate a CNS lesion

True

T or F: the presence of LMN lesion signs indicates that the patient has a PNS lesion

False (it can indicate either a PNS or CNS lesion)

*Yes, Struttin said he would be tricky like that

Where do UMNs originate from?

Motor cortex

brainstem motor nuclei

T or F: The corticobulbar tract is classified as pyramidal

True (it does not pass through the pyramids, but is considered part of the pyramidal system)

Where does the corticobulbar tract terminate?

brainstem

What does the corticobulbar tract control?

The upper part of both sides of the facial nucleus

What is the name of LMN peripheral nerve damage to the facial nerve, causing weakness of the entire ipsilateral side of the face?

Bell's palsy

How does UMN lesion to the face present?

Weakness of the contralateral face, sparing the forehead

What % of corticospinal tract fibers decussate and descend as the lateral corticospinal tract?

80-90%

Which tracts are in the lateral motor system?

Lateral corticospinal

Rubrospinal

Which tracts are in the medial motor system?

Anterior corticospinal

Vestibulospinal

Reticulospinal

Tectospinal

What parts of the ventral grey horn do lateral motor system tracts synapse in?

Lateral and posterior parts

What parts of the ventral grey horn do the medial motor system tracts synapse in?

Medial and anterior parts

T or F: The lateral motor system controls muscles in the limbs, especially flexors

True

Which motor system provides background posture and tone of the trunk and proximal limbs?

Medial motor system

Which tract controls intrinsic muscles of the spinal column?

Vestibulospinal tract

T or F: Postural muscles of the spine receive contralateral innervation

False (BILATERAL innervation)

Where does the vestibulospinal tract originate?

Vestibular nuclei at the pontomedullary junction of the brainstem

What provides the vestibular nuclei input concerning head position and movement?

Vestibular receptors in the inner ear

What part of the spinal cord is the Vestibulospinal tract located in?

Anterior column

Ascending projections from which tract innervates CN III, IV, and VI?

Medial longitudinal fasciculus

Which tract helps coordinate head and eye movements?

Medial longitudinal fasciculus

Which tract originates from the superior colliculi of the midbrain?

Tectospinal tract

What part of the spinal cord is the tectospinal tract found in?

Anterior column

What is the function of the tectospinal tract?

Reflex head turning in response to visual and auditory stimuli

Where does the reticulospinal tract originate?

reticular formation of the brainstem

What part of the spinal cord is the reticulospinal tract found in?

Anterior and lateral columns

T or F: The fibers of the reticulospinal tract are both crossed and uncrossed

True

T or F: Innervation of the rubrospinal tract is contralateral

True

Where does the rubrospinal tract originate?

Red nucleus of the midbrain

Where does the rubrospinal tract decussate?

midbrain

What part of the spinal cord is the rubrospinal tract found in?

Lateral column

T or F: The rubrospinal tract is more developed in humans than in most other animals

False (it is more important in animals)

T or F: the rubrospinal tract descends down into the cauda equina

False (it descends only into the cervical cord)

Which motor system is the rubrospinal tract part of?

lateral motor system

What tract controls skilled movements of the limbs?

Lateral cortciospinal

What tract controls grosser movements of the limbs (e.g. gross shoulder movements)

Rubrospinal

Where are lower motor neuron nuclei located?

Brainstem motor nuclei

Ventral grey horn of the spinal cord

How many muscle fibers are innervated by an individual terminal branch of a LMN?

1

What is the term for a LMN and all the muscle fibers it innervates?

Motor unit

What type of motor neuron innervates extrafusal muscle fibers?

Alpha motor neurons

What type of motor neuron innervates intrafusal muscle fibers?

Gamma motor neurons

T or F: The more a gamma motor neuron fires, the less sensitive a muscle reflex will be

False (the more a gamma motor neuron fires, the more sensitive the muscle reflex will be)

T or F: The trochlear nerve innervates the contralateral Lateral Rectus muscle

False (it innervates the contralateral superior oblique muscle)

What is the common symptom of UMN and LMN lesions?

Weakness

What type of disorders can cause weakness?

UMN lesions

LMN lesions

NMJ disease

Muscle disease (myopathy)

What is the term for a neuron whose axons are bundled in descending motor tracts within the CNS?

Upper motor neuron

What tools are used to determine the location of a motor neuron lesion?

The distribution of the weakness

Associated findings on other aspects of the motor exam, reflex exam, and sensory exam

History

How does UMN lesion weakness present in the upper extremity?

Posterior muscles are weaker than anterior muscles

How does UMN lesion weakness present in the lower extremity?

dorsal weaker than plantar muscles (quadriceps are hypertonic, knee is straightened)