Chapter 8: Control of Movement Flashcards
Ultimate function of nervous system:
control of behavior
_______ muscles move us around and are responsible for physical actions.
Skeletal
Strong bands of CT that fasten muscle to bones
Tendons
Flexion is the contraction of a flexor muscle that moves the limb toward/away from the body.
Toward
Extension is the contraction of an extensor muscle that moves the limb toward/away from the body.
Away from
The extrafusal/intrafusal muscle fibers provide the force of the muscle.
Extrafusal
Several extrafusal muscle fibers are served by a single axon of an _______ _____ ______.
alpha motor neuron
The intrafusal muscle fiber is served by _ axons: ________.
2; sensory and motor
Which part of the intrafusal muscle fiber contains the sensory endings sensitive to stretching?
Capsule
Which neuron causes the intrafusal muscle fiber to contract (albeit minimally)?
Gamme motor neuron
What does a motor unit consist of?
Alpha motor neuron
Axon
Associated extrafusal muscle fibers
Fine motor muscles such as the eyes or fingers will have more/less extrafusal muscle fibers per alpha motor neuron.
less
Gross motor muscles such as the limbs or butt will have more/less extrafusal muscle fibers per alpha motor neuron.
more
A muscle fiber is made up of a bundle of ______.
myofibrils (actin and myosin)
What are myosin cross bridges?
Little motile elements on the myosin that interact with actin and produce muscular contractions
_______ occur where the actin and myosin overlap on a muscle fiber
Striations
The synapse between the terminal button of an efferent neuron and the membrane of a muscle fiber:
Neuromuscular junction
In the neuromuscular junction, the terminal buttons synapse on _____ _________.
motor endplates
True or false: the endplate potential always causes muscle fibers to fire.
True
The depolarization of the postsynaptic membrane caused by the liberation of acetylcholine by the terminal buttons when an axon fires is called the _____ ______.
endplate potential
The endplate potential is a hyperpolarization/depolarization of the postsynaptic membrane
depolarization
The strength of a muscular contraction is determined by the _____ ____ ____ ________ of various motor units
average rate of firing
When the average rate of firing of various motor neurons is high, the contraction is strong/weak.
Strong
When the average rate of firing of various motor neurons is low, the contraction is strong/weak.
weak
True or false: intrafusal muscle fibers are stretch receptors that detect the total amount of stretch exerted by the muscle.
FALSE: they are stretch receptors that serve as muscle length detectors
Receptors on the intrafusal muscle fibers detect muscle _____, not tension
length
The golgi tendon organs encode the stretch degree by the ______ __ _______.
rate of firing
______ receptors detect the total amount of stretch exerted by muscle and are located within ______.
Stretch; tendons
The golgi tendon organ, monitoring the strength of contraction, fires in proportion to the stress on the muscle. Therefore, if weight was added to your hand, the firing increases/decreases.
increases
The monosynaptic stretch reflex controls ______ movements.
limb
During a monosynaptic stretch reflex, the muscle contracts in respond to being quickly ______ in reaction to a stimulus.
stretched
The monosynaptic stretch reflex helps to maintain _____ and adjusts to maintain ____ ______.
Posture; body position
Explain what happens during a monosynaptic stretch reflex:
Muscle lengthens, muscle spindle fires to the terminal buttons in gray matter of spinal cord, which synapse on the alpha motor neuron, innervating extrafusal muscle fibers and causing the muscle to move.
When gamma motor neurons are active,
muscle spindles become longer/shorter and are more/less sensitive to change
shorter; more
__________ reflexes involve multiple synapses involved in more complex reflexive behavior
Polysynaptic
Examples of a polysynaptic reflexes:
Pain; startle reflexes
True or false: You can’t control the polysynaptic reflex AT ALL.
False – we can kinda inhibit them thanks to context and learning.
Where is the primary motor cortex?
Posterior frontal lobe
The _______ ____ cortex is responsible for causing movements of particular parts of the body
Primary motor
The motor homunculus is a personification of the _____ _____ _____.
primary motor cortex
The supplementary motor area (SMA) is located on the medial/lateral surface of the brain.
Medial
The premotor cortex is located on the medial/lateral surface of the brain.
lateral
The motor association cortex is involved in _____ ________.
planning movements
The planning movements of the motor association cortex are executed in coordination with the _______ ______ _____.
primary motor cortex
The ____ controls sequences of motion
SMA
The _________ is involved with learning and executing complex movements that are guided by sensory information
Premotor Cortex
The _______ _____ _____ causes movements of particular parts of the body.
primary motor cortex
The ___ plays a critical role in behavior sequences
SMA
Damage to the SMA disrupts the ability to do ___________ _____
well-learned responses
The _______ _____ is involved in learning and doing complex movements, using arbitrary stimuli.
Premotor cortex
The reticular formation (RAS) controls the activity of the ______ ____ ____ and regulates the muscle tone.
Gamma motor system
When the gamma motor neurons are active, the muscle spindles are shorter/longer and hence more sensitive to ________ __ ______ _____.
shorter; changes in muscle length
When the muscle spindle is lengthened, the rate of firing will increase/decrease.
increase
As the firing rate of the efferent axon increases, the muscle spindle gets shorter/longer.
shorter
If the whole muscle gets shorter, there will be no stretch on the central region that contains the sensory endings, and the efferent/afferent axon will not respond.
afferent
If the muscle spindle contracts faster than the whole muscle does, there will be a considerable amount of efferent/afferent activity.
afferent
True or false: Most spinal polysynaptic reflexes are completely independent of the brain.
False; spinal reflexes do not exist in isolation and are normally controlled by the brain
The afferent axons from the ______ _____ ____ serve as detectors of muscle stretch.
Golgi tendon organ
There are _ types of afferent axons from the Golgi tendon organ. The more sensitive one tells the brain ________. The less sensitive ones synapse on _______ _____ _________.
2; how hard the muscle is pulling; spinal cord interneurons
The _______ contains 80% of all brain neurons
Cerebellum
The cerebellum outputs project to every major motor/sensory structure in the brain
Motor
If damage occurs to the cerebellum, it results to _____ ______ _____
jerky, erratic movements
Jobs of the cerebellum:
Smooth out and correct movements
The cerebellum has _ hemispheres
2
The flocculonodular lobe of the cerebellum is important for _______.
balance
The basal ganglia receive most of their input from all regions of the ________ _____ and the _____ ____
cerebral cortex; substantia nigra
The basal ganglia is kinda wrapped around the ______.
thalamus
The _____ ______ influence movements under control of the primary motor cortex and exert some direct control over the ventromedial system.
basal ganglia
The basal ganglia can control some inhibition of ______ movements
unwanted
Two neurodegenerative disorders of the basal ganglia include:
Parkinson’s disease
Huntington’s disease
Parkinson’s disease is caused by the death of ____ cells in the ______ _____
DA-secreting cells in the substantia nigra
Huntington’s disease is caused by the death of _____ and ____ cells in the ______.
GABA & ACh cells in putamen
__________’s disease is not enough movement
Parkinson
________’s diseases is too much movement
Huntington’s
The direct pathway of the basal ganglia is excitatory/inhibitory
excitatory
The indirect pathway of the basal ganglia is excitatory/inhibitory
inhibitory
The hyperdirect pathway of the basal ganglia is excitatory/inhibitory and acts very slowly/quickly
inhibitory/quickly
The lateral group is responsible for control of ___________ _____ movements, especially the ____ and ______.
independent limb; hands and fingers
The ventromedial group controls ________ movements of the _____.
automatic, gross; trunk, including coordinated movements needed for posture and locomotioin
Lateral corticospinal tract controls ______, ____, and ____ for _________.
Fingers, hands, arms; grasping and manipulating objects
The rubrospinal tract controls _____, ______, ___, and ______ for ____________
hands (not fingers), lower arms, feet, and lower legs; movement of forearms and hands independent from the trunk
The corticobulbar tract controls the ____ and ______ for _________.
face and tongue; face and tongue movement
aIPS is the ______ region
grasping
The mirror neurons are located in the rostral part of the ______ _____ lobe and the ______ _____ area
inferior parietal; ventral premotor
The ______ _______ respond when an individual engages in, observes, or hears a behavior, helping us to understand and imitate the actions of others.
mirror neurons
True or false: the mirror neurons fire when they see OTHER PEOPLE do movements.
True; it may help us understand or imitate the behavior
Most reaching behavior is controlled by _____.
Vision
The dorsal stream of visual association cortex contributes spatial information to the ______ _________ _____ when reaching to determine the location of target and supply information
parietal reaching region
True or false: We have special parts of the brain that help us identify biological motion (person moving versus a tree)
True
True or false: Apraxia is paralysis or weakness
FALSE: It’s more like you can’t understand movement, even though you can perform it.
Limb apraxia is produced by lesions of the ____ ______ or _____ lobes
left frontal or parietal lobes
______ apraxia is a deficit in the ability to perceive and imagine geometrical relations
Constructional
Constructional apraxia results in trouble _______ ______ or ________ _____.
drawing pictures; construction models. No legos for you.
Constructional apraxia is caused by lesions of the _____ _______, especially the ____ _____ lobe
right hemisphere; right parietal
Dyspraxia involves difficulties in complex motor behaviors, such as _____ _____ and _____.
planning, organizing, and coordinating
True or false: dyspraxia is more severe than apraxia.
False. Other way around.
True or false: 5-10% of children exhibit dyspraxia symptoms, but this can be fixed pretty easily.
True
