Phys 2 exam 2 (motor control)

Voluntary actions are under ______ control coordinated by the ___________

conscious; primary motor cortex

- fine detailed mvnt (hand/feet or facial muscles)

Learned patterns of movement are controlled by ______

basal nuclei (ganglia)

maintenance of posture and muscle tone controlled by ________

extrapyramidal tracts and muscle spindles

involuntary reflexes coordinated by ______

spinal cord

coordinated actions that are reliant in sensory/motor integration of the ________

cerebellum

The primary motor cortex is the origin of was tracts?

corticospinal (pyramidal)

T/F corticospinal tracts are a direct pathway to spinal cord, produce voluntary mvnt of skeletal muscle, and involve upper motor neurons

TRUE

Where do extrapyramidal tracts originate?

basal nuclei

What are extrapyramidal tracts responisble for?

indirect/reflexive and postural mvnt

The cerebellum coordinates ________ activity

smooth muscle

Basal nuclei coordinate the _______ & ________ of motor cortex

inhibition; activation

What prepares patterns of mvnt for the primary motor cortex?

pre-motor or supplementary motor cortex

Where does the supplementary motor cortex receive info from?

basal nuclei and cerebellum via Thalamus

Where are lower motor neurons located?

ventral horn of spinal cord

The precentral gyrus is the location of BA 4 and what?

primary motor cortex

T/F surgical removal of primary motor cortex causes a loss of fine motor control in proximal extremities

FALSE

- loss of fine motor control of distal extremities

Does surgical removal of the primary motor cortex affect the gross mvnt?

NO

What are the main output cells of the primary motor cortex?

giant Betz cells

- large and myelinated (fast)

What are output of the primary motor cortex?

Corticobulbar (CN)

Inferior olivary nucleus and pontine nucleus to cerebellum

extrapyramidal nuclei/tracts

T/F the Primary motor cortex receives some sensory info?

TRUE

The premotor area is guided by _______

sensory external stimuli

What area of the motor cortex is responisible for mental rehearsal, learning, and planning?

supplementary motor area

In stroke victims, the _________ would allow one to smile when told a joke and the ___________ would not allow one to smile even when told to indicating that is areas is ________

premotor area, supplemental motor area; damaged

Damage to _________ causes impaired motor production of speech and appropriate respiratory fxn of speech

Broca's area

What does damage to the hand skills area of the motor cortex cause?

motor apraxia

- inability to perform fine hand mvnt

Which area of the motor cortex coordinates head and eye mvnt?

eye fixation and head rotation area

Damage to Wernicke's area leads to what?

decreased speech comprehension --> incorrect choice of words (Fluent aphasia)

T/F Wernicke's area is part of the motor cortex

FALSE

Corticospinal tracts are ________ projection fibers that pass by the basal nuclei and thalamus within the _________ of internal capsule and extend through brain stem and cross

descending; posterior limb

What corticospinal tract supplies appendicular muscles and all fibers cross at jxn of medulla and spinal cord?

Lateral corticospinal tract

What corticospinal tract supplies axial muscles and ~50% fibers cross at cord level where synapse occurs?

Ventral corticospinal

Stimulatory fxn of primary motor cortex activates _________ and damage results in loss of _________ mvnt

corticospinal tracts; voluntary

Inhibitory fxn of primary motor cortex inhibits ________ mvnt and damage results in loss of _______ of unintended mvnt

unintended; inhibition

What would a lesion of the motor cortex result in?

loss of voluntary control & inhibition --> spastic paralysis

What controls posture and contains centers of repetitive mvnt and equilibrium?

brainstem

______ and ______ nuclei/tracts control ipsilateral anti-gravity/extensors

vestibular; pontine-reticular

______ and _____ nuclei/tracts control anti-extensors

Red nuclei & rubrospinal (contralateral/upper extremities); Medullary-reticular (bilateral)

Vestibular and pontine reticular nuclei activate and send signals down cord via _______ and _______ ipsilaterally

lateral vestibulospinal tract; pontine-reticulospinal tract (medial reticulospinal)

T/F the red nucleus contains large neurons similar to Betz cells

TRUE

What are characteristics of rubrospinal tract?

- crosses in midbrain

- terminates in thoracic spine

- strong stimulator of medullary reticulospinal tract

- inhibits anti-gravity activation of Pontine Reticulospinal tract

The red nucleus and rubrospinal tract function in what?

postural control and fine motor control

What transmits inhibitory signals to the anti-gravity muscles through medullary reticulospinal tract?

medullary reticular nuclei

Medullary reticular nuclei receive ________ input from corticospinal and rubrospinal tracts

collateral

What tract originates in the superior colliculus of the midbrain and controls visual, auditory and startle reflex?

tectospinal tract (only in cervical spine)

damage btw _______ and red nucleus results in loss of cortical inhibition of red nucleus which produces upper extremity flexion; this is referred to as _________ posturing. What tract does this involve?

cortex; decorticate

- rubrospinal tract

damage btw ______ and red nucleus results in loss of rubrospinal inhibition of vestibular/pontine-reticular tracts which produces upper extremity extension; this is referred to as ________ posturing

vestibular/pontine-reticular nucleus; decerebrate

The spinal cord contains interneurons for what?

reflexes and pain modulation

What neuron cells bodies are found in the spinal cord?

lower motor neurons

alpha motor neurons

gamma motor neurons

pre-ganglionic sympathetic neurons (T1-L2)

pre-ganglionic parasympathetic neurons (S2-S4)

Large ________ motor neurons supply _______ fibers and large mvnt producing muscle fibers

alpha; extrafusal

small ______ motor neurons supply _______ fibers and muscle spindles

gamma; intrafusal

Lateral grey horn from T1-L2 houses _______

preganglionic sympathetic neuron cell bodies

Lateral grey horn from S2-S4 houses _______

preganglionic parasympathetic neuron cell bodies

What are connections btw motor and sensory fibers?

interneurons

What are involuntary and predictable? What are some examples?

Intrinsic reflexes

- DTRs, GTO reflex, pain withdrawal

What are involuntary and learned only after repetition? What are some examples?

Acquired reflexes

- athletic mvnt, driving a car

What are the component of the reflex arc?

sensory receptor

sensory neuron

interneurons within spinal cord grey

morot neuron

effector (skeletal muscle or gland)

Deep tendon reflex (DTR) is another name for what?

stretch reflex

What is occurs when a quick stretch on nuclear bag triggers a quick contraction of a muscle?

Dynamic response of DTR

What is used to maintain muscle tone by sustained contraction of a muscle?

Static response of DTR

________ is the stimulation or contraction of a muscle that was quickly stretched, while antagonistic muscle is inhibited

stretch reflex (DTR)

Reciprocal inhibition

used to describe the inhibition of antagonistic muscle group

lesion of UMN leads to ______, which is excessively strong, spasm like, short-lived sustained contraction. This is a problem in the ______

hyperreflexia; brain

lesion of LMN leads to ________, which is reduced or absent reflexes. This occurs in the ______

hyporeflexia; PNS

________ is the inhibition of muscle/tendon under too much tension

golgi tendon reflex

What term is used to describe the golgi tendon reflex process and is used in PNF stretching?

autogenic inhibition

Another name for flexor withdrawal reflex

pain withdrawal reflex

motor units are ___ motor neuron and the ________ it innervates

1; muscle fibers

1 motor neuron and 1 muscle fiber = ______

What are some examples?

fine control

ex) extraocular eye muscles, laryngeal, tongue, hands

1 motor unit and 1000 muscle fibers = _____

What are some examples?

coarse control

ex) glutes, quads

Which motor units are recruited first, and how much of a contraction do they produce?

smallest; small tension/contraction

What is the last motor unit to be recruited and how much of a contraction do they produce?

largest; greatest tension/contraction

T/F the smallest motor units have a high threshold requiring more frequency of APs to activate

FALSE

the largest motor units have a high threshold and the smallest have a low threshold

increase in number of fibers stimulating motor units is referred to as __________

mulit-fiber summation (spatial)

increase in frequency of signals to motor unit is ________, which can lead to tetany (constant contraction)

frequency summation (temporal)

Muscle tone is regulated by _______ from muscle spindles and _______ from the brain and anterior grey of cord

afferents; efferents

T/F UMN exert a strong inhibitory force on muscle tone

TRUE

T/F the result of UMN lesion is spastocity and abnormal increase in reflexes

TRUE

______ carry motor signal from anterior horn of cord to NMJ

LMN

T/F the result of LMN lesion is flaccidity/weakness and abnormal decrease in reflexes

TRUE

What work together to coordinate smooth motor control?

basal ganglia, thalamus, cerebellum

What is the result of lesion to basal ganglia, thalamus, cerebellum?

dystonia (altered control/unintended mvnt)

T/F basal ganglia are important for starting, stopping, and controlling the frequency of mvnt and controlling patterns of repetitive mvnt

FALSE

intensity of mvnt

______ pathway inhibits stimulation of motor cortex

indirect

______ pathway stimulates og motor cortex

direct

All of the following are components of the basal nuclei EXCEPT

striatum

globus pallidus

corpus callosum

substantia nigra

subthalamic nucleus

corpus callosum

What component of the basal nuclei is the input and includes the caudate and putamen?

striatum

what component of the basal nuclei is the output and contains internal and external portions?

globus pallidus

General process of putamen circuit

1) originate in premotor and supplemental motor cortex

2) signals processed in basal ganglia

3) signals end up back in primary motor cortex via thalamus

the _____ putamen circuit is stimulatory to motor cortex and allows for _______ mvnt

direct; intended

the _____ putamen circuit is inhibitory to motor cortex and prevents ______ mvnt

indirect; unintended

What pathway does dopamine utilize?

Nigrostriatal pathway

the direct pathway is _______ by dopamine

stimulated

net increase in mvnt

the indirect pathway is ______ by dopamine

inhibited

net increase in mvnt

Excess dopamine will cause ________ intended mvnt and decreased inhibition of i=unwanted mvnt; whereas less dopamine will ______ intended mvnt

increased; decrease

Degeneration of substania nigra causes a decrease in dopamine, which leads to less stimulation of the direct pathway to the cortex resulting in difficulty ________ mvnt which is a characteristic of _________

producing; Parkinson's Disease

What is associated with cerebral palsy and is characterized by spontaneous writhing movements of the hand, arm, neck, and face?

athetosis

What is the flicking or dance-like mvnt of hands, face, or shoulders?

chorea

What is the sudden flailing mvnt of an entire limb?

hemiballismus

A lesion of the substantia nigra would lead to rigidity, tremor, akinesia, and a loss of dopaminergic input from substantia nigra to caudate and putamen resulting in _________

Parkinson's Disease

A lesion to the Caudate and putamen would cause of loss of GABA releasing neurons to globus pallidus and substantia nigra resulting in ________

Huntington Chorea