Movement - Exam 4 Flashcards
Ultimately, the brain is linked to the concept of ______
Movement
Internal processing would be useless without the ability to do what?
Move
All animal movement depends on what?
Muscle contractions
What are the 3 types of muscle?
Smooth, skeletal, and cardiac
What does smooth muscle do?
Control the digestive system and other organs
What does skeletal muscle do?
Skeletal muscle (striated muscle) controls movement of the body in relation to the environment
What does cardiac muscle do?
Heart muscles that have the properties of skeletal and smooth muscles, they keep the heart beating
What do smooth muscle cells look like?
They’re long thin cells; found in the intestines and other organs
What is another name for skeletal muscle?
Striated muscle
What do skeletal muscle cells look like?
Long and cylindrical fibers with stripes; control body movement
What do cardiac muscle cells look like?
Fibers that fuse together at various points to contract together rather than independently; found in the heart
What are muscle fibers composed of?
Muscle fibers are composed of many individual fibers
Each muscle fiber receives information from how many axons?
One axon
How many muscle fibers may a single axon innervate?
Many muscle fibers
What is a neuromuscular junction?
A special kind of synapse between a motor neuron axon and a muscle fiber
What type of synapse is between a motor neuron axon and a muscle fiber?
A neuromuscular junction
What causes the muscle to move/ contract?
The release of acetylcholine
How can movements be more precise?
Movements can be more precise where each axon innervates only a few fibers (like in eye muscles) than where it innervates many fibers (like in biceps muscles).
How are fine motor movements created?
By one axon innervating only a few muscle fibers
Messages from a motor neuron to specific muscle fibers (via acetylcholine) can only do what?
Tell the muscle to contract
How do motor neurons communicate with specific muscle fibers?
Acetylcholine
Define antagonistic muscles
Opposing sets of muscles
Movement requires what?
The alternating contraction of opposing sets of muscles called antagonistic muscles
What are the two categories of muscles [based on the way they move]?
Flexor and extensor muscles
Define flexor muscle
A muscle that flexes or raises an appendage (like the bicep)
Define extensor muscle
A muscle that extends an appendage, or straightens it (like the triceps)
What are the two types of skeletal muscle fibers?
Fast-twitch fibers and slow-twitch fibers
Describe slow-twitch fibers
Skeletal muscle fibers that produce slower contractions with slower fatigue (i.e. tongue muscle fibers used for talking)
Describe fast-twitch fibers
Skeletal muscle fibers that produce fast contractions but fatigue rapidly (i.e. muscles for sprinting or climbing)
What factors influence the percentages of fast-twitch and slow-twitch muscles?
Genetics and degree of muscle training
Describe how the type of training impacts the ratio of fast and slow twitch fibers
Olympic sprinters will have significantly more fast-twitch fibers in their legs than most of us, whereas olympic marathon runners will have significantly more slow-twitch fibers in their legs
Are slow-twitch fibers aerobic or anaerobic?
Slow-twitch fibers are aerobic and require oxygen during movement and therefore do not fatigue.
Nonstrenuous activities utilize what fibers?
Slow-twitch and intermediate fibers
Are fast-twitch fibers aerobic or anaerobic?
Fast twitch fibers are anaerobic and use reactions that don’t require oxygen, but need “gulps” (so to speak) of oxygen to recover - resulting in muscle fatigue
Behaviors requiring quick movements utilize what fibers?
Fast-twitch
Why does anemia cause weakness?
Oxygen needs to bind to iron (to make hemoglobin, which is in red blood cells) in order to be transported to muscles. Low iron means fewer vehicles to transport the oxygen
Define proprioceptors
Receptors that detect the position or movement of a part of the body
What do proprioceptors do?
They help us know where we are in relation to the space around us
What do muscle proprioceptors do and how?
They help us orient our movements as we interact with our environment. They do this by sending afferent sensory messages to the spinal cord, which then adjust movements by sending back efferent motor messages
What is a muscle spindle?
One type of proprioceptor, they run parallel to muscles and respond to the stretching or tensing of the muscle [imagine your ankle starting to twist as you step off the curb]
Name two type of proprioceptor
Muscle spindles and golgi tendon organs
When does a stretch reflex occur?
When muscle proprioceptors detect the stretch and tension of a muscle and send messages through afferent sensory neurons to the spinal cord, which then sends messages to contract the muscle with efferent motor neurons (can be used to balance your ankle)
A stretch reflex reacts to what?
A stretch reflex reacts to stretching/tension of the muscle by counteracting it; it doesn’t cause the muscle to stretch
True or false: A stretch reflex causes your muscle to stretch
False
What are the two things involved in a stretch reflex?
The golgi tendon organs and muscle spindles
What is the golgi ttendon organ?
Another type of proprioceptor that responds to an increase in muscle tension
Where is the golgi tendon organ located?
The tendons at the opposite ends of the muscle
What does the golgi tendon organ do?
It acts as a “brake” against excessively vigorous contraction during the stretch reflex, which could result in injury or over-correcting. It does this by sending an impulse to the spinal cord, where motor neurons are then inhibited by interneurons
What would happen if the stretch reflex happened without the golgi tendon organ?
Injury or over-correction, since the golgi tendon organ acts as a brake against excessively vigorous contraction
Explain the regulation of muscle contractions
When a muscle is stretched, nerves from the muscle spindles transmit impulses that lead to contraction of the muscle. Contraction of the muscle stimulates the Golgi tendon organ, which acts as a brake or shock absorber to prevent a contraction that is too quick or extreme.
What regulates muscle contractions?
Two kinds of proprioceptors: muscle spindles and the golgi tendon organ
When you get your knee tapped at the doctor’s office, what happens?
A stretch reflex. The tap stretches the extensor muscles and their spindles, resulting in a message that jerks the lower leg upward. A leg that jerks excessively or not at all may indicate a neurological problem
Define reflex
An involuntary, consistent, and automatic response to stimuli
Most movements are a combination of what two things?
A combination of voluntary and involuntary; reflexive and nonreflexive
Movements vary with respect to what?
Feedback
Define ballistic
A movement that cannot be changed once initiated (ex: reaching/pointing or striking/punching/throwing)
What are the two categories of feedback?
Ballistic and guided by feedback
Many behaviors consist of ____ sequences of _____ movements
Many behaviors consist of rapid sequences of individual movements
Define central pattern generators
Neural systems in the spinal cord or elsewhere that generate rhythmic patterns of motor output and are determined by the animal’s genes
Give examples of central pattern generators in animals
Wing flapping in birds or “wet dog shake”
Give examples of central pattern generators in humans
Chewing movements; walking; standing; urinating
Define motor program
A motor program is a fixed sequence of movements that is either learned and “programmed” into memory or built into the nervous system (via central pattern generator)
True or false: Motor programs are ballistic
True
Describe how automatic a motor program is
It’s automatic in the sense that thinking or talking about it interferes with the action
What doesn’t need afferent input from the environment to happen?
Motor programs; in fact, animal research and human case studies have found that some motor programs persist, even after blocking incoming sensory information (e.g., lesions; paralysis, mouse grooming itself, yawning).
True or false: Reflexes occur completely independently of the brain
False; while there are many movements that do not depend on the brain to occur (such as reflexes), these actions still “check in” with the brain, which then may tweak our movements to best fit environmental conditions.
True or false: Controlling movements only depends on the cerebral cortex
False; controlling movement depends on many areas of the brain
Give an example of an intentional movement
Scrolling to the next slide
Give an example of a learned habit that can seem automatic over time
Driving
Why is it important to understand how the brain controls movement? (give 3 out of the many reasons)
- It’s super fascinating.
- Offers insights and hopes for giving back movement after spinal cord damage or limb amputations
- Reveals the causes of movement disorders. Understanding causes is necessary as scientists try to find the best ways to treat, and possibly prevent, these disorders
What are the 4 lobes of the cerebral cortex?
The frontal, parietal, temporal, and occipital lobes
What does the occipital lobe of the cerebral cortex do?
It processes visual input
What does the temporal lobe of the cerebral cortex do?
It processes auditory information and helps form memories (thanks to the hippocampus)
What does the parietal lobe of the cerebral cortex do?
It processes touch sensations
What does the frontal lobe of the cerebral cortex do?
It controls fine motor movements, reasoning, higher level cognition, and expressive language
Describe the location of the primary motor cortex
The primary motor cortex is located in the precentral gyrus, which is a part of the frontal lobe, which is 1 of the 4 lobes of the cerebral cortex.
What generates impulses that control the muscles from head to toe?
Axons from the motor cortex connect to the brainstem and the spinal cord, which then generate the impulses that control the muscles from head to doe
What is involved in complex movements? Give an example
The cerebral cortex is additionally involved in complex movements, like playing tennis
What send out messages?
Pathways from the primary motor cortex, other cortical areas, midbrain, and medulla
Where do messages from the primary motor cortex go?
Usually to interneurons in the spinal cord that bridge these messages to the efferent motor neurons
Describe the pathway of messages to control muscles
Pathways from the primary motor cortex, other cortical areas, midbrain, and medulla send out messages—usually to interneurons in the spinal cord that bridge these messages to the efferent motor neurons. These motor neurons in the medulla and spinal cord are what directly synapse to muscles and control muscle contractions.
What directly synapse to muscles and control muscle contractions?
Motor neurons in the medulla and spinal cord
When is the primary motor cortex active?
When people intend to make a movement
What orders an outcome?
The primary motor cortex
True or false: the primary motor cortex not only orders movement, but its neural activity increases even when you are just thinking about moving
True
Describe contralateral control
Specific parts along the primary motor cortex (which is on both the left and right hemispheres) are responsible for controlling the muscles in specific body areas on the opposite side of the body (i.e., contralateral control). Left hemisphere PMC controls muscles on right side of body. Right hemisphere PMC
controls muscles on left side of body. Although, some overlap does exist
Larger amounts of surface area on the motor cortex are taken up by what areas of the body?
Areas of the body that have more fine and detailed motor movements (e.g., face and hands)
Describe the location of the motor cortex
The motor cortex lies just anterior to the somatosensory cortex (i.e., sense of touch).
The somatosensory area responsible for what part of movement?
Feeling/sensing that body part lines up with the motor area responsible for moving that body part.
Movement requires communication between what two areas of the brain?
The motor cortex and somatosensory cortex
True or false: Other areas near the primary motor cortex also contribute to movement
True
What does the posterior parietal cortex do?
It keeps track of the position of the body relative to the world. Damage to this area causes difficulty in coordinating visual stimuli with movement. Example: trouble finding objects in a room, even after describing their appearance. Important for planning what movements are needed
If you have trouble finding objects in a room, even after describing their appearance, you may have damage to what area of the brain?
The posterior parietal cortex
What dose the premotor cortex do and when is it active?
It’s active during preparation for movement. It receives information about a target and integrates information about position and posture of the body; organizes the direction of the movement in space
What does the supplementary motor cortex do and when is it active?
Organizes rapid sequence of movements in a specific order; inhibits old habits if necessary. Active seconds before the movement and active following an error in movement so you can inhibit the incorrect movement the next time
What does the prefrontal cortex do and when is it active?
Active during a delay before movement. Stores sensory information relative to a movement. Necessary for you to consider the probable outcomes of a movement
Define antisaccade task
Inhibits a saccade, which is a voluntary eye movement from one target to another
Describe what affects your ability to perform an antisaccade task.
Performing this task well requires sustained activity in parts of the prefrontal cortex and basal ganglia before seeing the moving stimulus. Ability to perform this task matures through adolescence. Performance on this task is impacted by neurological or psychiatric disorders associated with the prefrontal cortex and basal ganglia
Performing this task well requires sustained activity in parts of the prefrontal cortex and basal ganglia before seeing the moving stimulus. Ability to perform this task matures through adolescence. Performance on this task is impacted by neurological or psychiatric disorders associated with the prefrontal cortex and basal ganglia. What task am I describing?
Antisaccade task
Name one developing area of research
Mirror neurons
What are mirror neurons and what do they do?
Neurons that are active during both preparation of a movement and while watching someone else perform the same or similar movement.
May be important for understanding, identifying, and imitating other people. May be involved in social behaviors. Unknown whether they cause or result from social behavior. Possible implications in autism spectrum disorder and schizophrenia
Messages from the brain must reach the _____ and spinal cord to control the muscles using the ______ _________
Messages from the brain must reach the medulla and spinal cord to control the muscles using the corticospinal tracts
Define corticospinal tracts
Paths from the cerebral cortex to the spinal cord
True or false: different tracts contribute to all movements, but they also have specializations
True
What are two of the types of corticospinal tract?
The lateral corticospinal tract and the medial corticospinal tract
Describe the lateral corticospinal tract
A set of very long neuron axons projecting from the primary motor cortex, surrounding brain areas, and brain stem to the spinal cord. They travel on the lateral sides of the spinal cord (hence the name). Controls movement on the lateral (peripheral) areas of the body (e.g., hands and feet). Axons extend from one side of the brain to the opposite side of the spinal cord, and control opposite side of the body (i.e., contralateral control)
Describe the medial corticospinal tract
A set of axons from many parts of the cortex (not just the ones you’ve already learned about in the cerebral cortex). E.g., Reticular formation, midbrain tectum, and vestibular nucleus. Axons of the medial tract go to both sides of the spinal cord, not just to the contralateral side. The medial tract controls the muscles of the neck, shoulders, and trunk. Responsible for bilateral movements (i.e., when it’s helpful to have both sides moving)like walking, turning, bending, standing up, and sitting down many parts of the cortex (not just the ones you’ve already learned about in the cerebral cortex)E.g., Reticular formation, midbrain tectum, and vestibular nucleus•Axons of the medial tract go to bothsidesofthespinalcord,notjusttothecontralateralside•The medial tract controls the muscles of the neck, shoulders, and trunk. Responsible for bilateral movements (i.e., when it’s helpful to have both sides moving)like walking, turning, bending, standing up, and sitting down.
Where is the basal ganglia group?
Deep inside the brain and span within the midbrain and forebrain regions
Describe the cerebellum in basic terms and what happens if you damage it
A structure in the brain often associated with balance and coordination. More neurons in the cerebellum than in all other brain areas combined!
Damage to the cerebellum causes trouble with rapid movements requiring aim/timing. Examples: clapping hands, speaking, writing, and so on. The cerebellum is one of the first structures to be targeted by alcohol, which is why lack of coordination is a cardinal sign of intoxication
What is one of the first structures affected by alcohol?
The cerebellum
Describe what the cerebellum is important for (in regards to movement)
Important for establishing new motor programs that allow us to complete a “programmed” sequence of stop-and-go actions from start to finish. Also includes tasks that require good timing, in order for the sequence to actually work and achieve the goal. E.g.,speaking, typing, musical instruments, athletics. There are other movements that are oftentimes forgotten as being forms of “movement”. The cerebellum is also critical (along with other brain areas) for certain aspects of attention, such as the ability to shift attention from one task to the other, as well as attending to visual stimuli in the environment
What helps establish new motor programs?
The cerebellum
Describe what the cerebellum is important for besides movement
It responds to sensory information even in the absence of movement. It also responds strongly to violations of sensory information. Ex: reaching to touch something but not feeling it, or feeling something when you don’t expect to feel it. In these situations, the cerebellum is like, “Hey! What’s going on?” and is cued to figure out a solution for coordinated movements
What are the two layers of the cerebellum? Describe them.
- Cerebellar cortex (the outer surface layer that you can see)
- Nuclei of the cerebellum (clusters of cells inside of the cerebellum)
What are the two types of cells in the cerebellar cortex?
Purkinje neurons and parallel fibers
Describe Purkinje neurons and parallel fibers
Purkinje neurons: flat, parallel neurons in sequential rows (you can see their dendrites and cell bodies, below).
Parallel fibers: long axons stretching parallel to one another; perpendicular to rows of of Purkinje neurons
How are cerebellar cortex neurons arranged?
Cerebellar cortex neurons are arranged in precise, repeated geometrical patterns that provide outputs of well-controlled duration
Describe how messages are sent within the cerebellum
Action potentials from the axons of parallel fibers excite Purkinje cells/neurons, one after the other in rows. The longer the parallel fibers send messages, the longer the response of the Purkinje neurons. Purkinje cells are inhibitory neurons. Thus,when they are excited by the parallel fibers, they then transmit inhibitory neurotransmitters to:
1.Cells in the nuclei of the cerebellum (clusters of cell bodies inside of the cerebellum) and
2.Cells called vestibular nuclei in the brain stem (i.e., the evolutionarily old “lizard part” of your brain that extends into the spinal cord).
CONTEXT:“vestibular disorders”(if you’ve heard of them) are those related to loss of balance
Where do Purkinje neurons send their inhibitory messages to?
Cells in the nuclei of the cerebellum and vestibular nuclei
Define cells in the nuclei of the cerebellum and vestibular nuclei
Cells in the nuclei of the cerebellum (clusters of cell bodies inside of the cerebellum) and
2.Cells called vestibular nuclei in the brain stem (i.e., the evolutionarily old “lizard part” of your brain that extends into the spinal cord).
Why would the Purkinje neurons inhibit these deep cerebellar nuclei and vestibular nuclei?
The cerebellum plays a critical role in stop-and-go actions and regulating the critical timing of motor program sequences. Purkinje cells regulate the timing of action potentials in these deeper nuclei. It’s like they are the bouncers of an action potential party—so that your movements don’t get too rowdy.
What is the basal ganglia?
A group of large subcortical structures in the forebrain; at the base of forebrain and midbrain. Responsible for self-initiating an action not guided by a stimulus (i.e., actions that are proactive, not reactive)
Basal ganglia make up what structures?
- Caudate nucleus
- Putamen
- Globus pallidus
- Substantia nigra (if it’s messed up it results in parkinsons) 5.Subthalamicnucleus
What do the basal ganglia structures do and what do they surround?
They act as bouncers and create movement by ceasing to inhibit it. They surround the thalamus.
What types of actions do the basal ganglia play an important role in?
Complex, self-initiated movements. Forming habits (both the good and bad ones). What you do (or don’t) pay attention to in the environment. Determining the vigor of the movements that were “ordered by” the primary motor cortex (located in the frontal lobe of the cerebral cortex) (more detail in module 4)
When learning a new movement, the ___ lobe is highly involved.
Frontal
Describe motor learning and network formation
The learning of new skills requires multiple
brain areas involved in the control of movement. The pattern of activity of the neurons in the motor cortex becomes more consistent as a new skill is
learned. At first, the movements are slow and inconsistent,
like when learning to ride a bike. Over time, neurons start to form networks and increase their firing rates as you become better at the movement
___ _____ are critical for turning new motor
skills into “automatic” behaviors and new habits and organizing the sequences of movement,
(Example: after driving a car for a while, using all of the gizmos and gadgets in their correct sequence starts to become automatic)
Basal ganglia
True or False: The conscious decision to move, and the
movement itself, occur at the same time
False: The conscious decision to move, and the movement itself, occur at two different times
Describe a readiness potential
A readiness potential is a particular type of
activity in the motor cortex that occurs before any type of voluntary movement. Begins at least 200 milliseconds before the movement. Implies that we become aware of our decision to move after the process has already begun.
Seizure disorders are characterized by what?
Seizure disorders are characterized by abnormally high excitation in neurons.
True or false: Not all people who appear to have seizures have epilepsy
True
Describe epilepsy and why it happens
Epilepsy is a seizure disorder that is characterized by repeated episodes of excessive, synchronized neural activity
These episodes happen as a result of suppression of GABA
Describe Symptomatic Seizure Disorders
Those where a specific cause can be identified with a specific cause
Trauma, infection, tumor, toxins
Describe Idiopathic Seizure Disorders
Those that appear spontaneously and in the absence of other diseases of the central nervous system
Describe partial seizures
Electrical discharges in a relatively small group of dysfunctional neurons in one cerebral hemisphere. Aura (warning) may reflect site of origin. May or may not result in a loss of consciousness (LOC)
Describe generalized seizures
Diffuse abnormal electrical discharges from both hemispheres. Both hemispheres are involved symmetrically. No warning. Always experience a loss of consciousness (LOC)
What are the two types of generalized seizure?
Grand Mal Seizure and Petit Mal Seizure
Describe grand mal seizures
Characterized by loss of consciousness and stereotyped motor activity. Tonic stage: body stiffens and breathing stops. Clonic stage: rhythmic shaking
Describe petit mal seizures
Brief duration and characterized by loss of awareness with no motor activity except for blinking, turning the head, or rolling the eyes
True or false: Partial seizures affect the whole brain
False; partial seizures affect localized regions of the brain. Generalized seizures affect the whole brain
What are the two general treatments for epilepsy?
Anticonvulsant drugs or surgery
Describe the 4 types of surgeries performed to treat epilepsy
Lobe resection-remove the seizure focus;
Corpus callosotomy - this stops communication between the hemispheres and prevents the spread of seizures from one side of your brain to the other;
Multiple subpial transection (MST) - a series of shallow cuts in the brain tissue to interrupt the flow of seizure impulses but don’t disturb normal brain activity;
Functional hemispherectomy- the hemisphere left in place but disconnected from the rest of your brain; only a limited area of brain is removed (mostly for children younger than 13).
Define degenerative disorders and give 2 examples
Disorders that continue to worsen over time and are caused by degeneration (withering) of brain cells. Ex: Parkinson’s, Huntington’s
Describe Parkinson’s disease
Parkinson’s disease (PD) is a chronic, progressive neurodegenerative movement disorder. However, it is now known to have variety of non-motor symptoms as well
What are the most common symptoms of Parkinson’s?
Tremor (shaking usually starts on one side of the body, often in the hand or finger)
Rigidity (stiffness where the limbs feel like lead)
Akinesia (difficulty in initiating movement and slowness of movement)
Problems with balance
What causes Parkinson’s?
Caused by gradual and progressive death of neurons, particularly in an area of the midbrain called the substantia nigra. In a health individual the neurons in the substantia nigra secrete significant amounts of dopamine and send that dopamine to the the basal ganglia; For reasons not yet understood, the dopamine-producing nerve cells of the substantia nigra begin to die
What happens in Parkinson’s patients when around 80-90% of dopamine is lost?
PD symptoms such as tremor, slowness of movement, stiffness, and balance problems occur.
Describe the risk factors for Parkinson’s
Early-onset PD (diagnosed before age 50) has a genetic link. However, late onset PD (after age 50), appears more clearly linked to environmental factors – like exposure to toxins.
Describe the available drug treatments Parkinson’s treatments
Drug Treatments are most common for PD. But no drug treatment cures the disease.
L-DOPA is the most commonly used drug. It is a precursor for dopamine, so once inside the blood brain barrier it only supplies the brain with dopamine – it does not prevent the continued loss of neurons within the substantia nigra (it alleviates the problem – it doesn’t fix it).
Deprenyl - attacks the other end of the dopamine-preservation process by inhibiting the action of the MAO-B – enzyme that breaks down dopamine
Describe the non-drug treatments for Parkinson’s
An alternative treatment is Deep Brain Stimulation.
For this treatment, a device is implanted (by surgeons) into the patient’s brain.
The device delivers high frequency electrical stimulation of the globus pallidus – a section of the basal ganglia that does not rely on dopamine.
This stimulation stops most tremors and enhances the patient’s movement.
Describe Huntington’s disease
An inherited condition on chromosome 4 in which nerve cells within the basal ganglia break down over time
Characterized by progressively more severe uncontrollable jerk movements, writhing movements, dementia, and finally death
At present, there is no treatment for Huntington’s disease
Describe the symptoms of Huntington’s
Symptoms tend to begin in person’s thirties and forties, sometimes as early as in infancy.
Movements look like fragments of purposeful movements, occur involuntarily
Disease is progressive, includes cognitive and emotional changes,
Death usually occurs within ten to fifteen years after symptoms begin
A ballistic movement ____.
a) is guided by feedback during the course of the movement
b) proceeds automatically once it has been triggered
c) tends to overcorrect itself
d) is a rhythmic alternation between two movements
b) proceeds automatically once it has been triggered
A boxer’s ability to sense the position of his arm and hand before planning a punch is fundamentally dependent on the sense of ____.
a) vision
b) proprioception
c) pain
d) somatosensation
b) proprioception
A motor program is a ____.
a) mechanism that guides movement on the basis of sensory feedback
b) mechanism that produces an alternation between two movements
c) plan for training a brain-damaged person to walk
d) movement that, once triggered, continues automatically until its completion
d) movement that, once triggered, continues automatically until its completion
A muscle spindle responds to the ____.
a) stretch of the muscle
b) oxygen level in the muscle
c) fatigue of the muscle
d) acetylcholine concentration
a) stretch of the muscle
A physician who asks you to cross your legs and then taps just below the knee is testing your ____.
a) stretch reflexes
b) slow reflexes
c) constriction reflexes
d) fast reflex
a) stretch reflexes
Exercising at a high altitude where there is less oxygen is most likely to affect ____.
a. anaerobic contraction
b. fast-twitch fibers
c. intermediate fibers
d. slow-twitch fibers
d. slow-twitch fibers
Moving a leg or arm back and forth requires opposing sets of muscles known as \_\_\_\_\_\_\_\_. reflex muscles paired muscles agonistic muscles antagonistic muscles
antagonistic muscles
The role of the Golgi tendon organs is to ____.
produce rapid repetitive movements, such as finger tapping
prevent extreme muscle contractions
guard against fatigue of muscles
regulate blood flow to the tendons and muscles
prevent extreme muscle contractions
What type of muscle is responsible for the movement of your body through the environment? Striated Cardiac Smooth Syncarpous
Striated
Which behavior is most likely to result from the activity of central pattern generators? A child playing the piano A child catching a baseball A bird flying An adult yawning
A bird flying
Lucina is painting with a small brush in each hand. To do this movement, she needs activation via the \_\_\_\_\_. medial tract lateral tract dorsal tract ventral tract
lateral tract
Recent studies about voluntary movements and conscious decisions have found that ____.
voluntary movements are the result of free will
we are unable to judge when we make conscious decisions
we are conscious of our decision before brain activity is generated for movement
brain activity for the movement begins before we are conscious of our decision
brain activity for the movement begins before we are conscious of our decision
Saccades are initiated by the \_\_\_\_. hippocampus spinal cord hypothalamus cerebellum
cerebellum
The basal ganglia are crucial to \_\_\_\_. involuntary movements unlearned movements self-initiated movements reflexive movements
self-initiated movements
The cerebellum is most important for any process that requires ____.
precise timing
detecting the intensity of a stimulus
comparison between the left and right hemispheres
control of muscle strength
precise timing
The corticospinal tract extends from the \_\_\_\_\_ . basal ganglia to the spinal cord cerebral cortex to the spinal cord spinal cord to the cerebellum cerebral cortex to the cerebellum
cerebral cortex to the spinal cord
The lateral tract crossover point is in the \_\_\_\_. vestibular nucleus pyramids of the medulla spinal cord reticular formation
pyramids of the medulla
The motor cortex _____.
relies on feedback from individual muscle fibers
sends axons to the brainstem and spinal cord
has direct connections to the muscles
controls isolated movement in a single muscle
sends axons to the brainstem and spinal cord
The structure composed of the caudate nucleus, putamen, and globus pallidus is the \_\_\_\_. limbic system cerebellum basal ganglia sympathetic nervous system
basal ganglia
Which widely branching cells are responsible for all of the output from the cerebellar cortex to the nuclei of the cerebellum? Spindle fibers Parallel fibers Purkinje cells Putamen cells
Purkinje cells
