Deck 10: Control Body Movement

Question 1

Which is a symptom of Parkinson's disease?

A)Flaccid paralysis
B)Intention tremor
C)Resting tremor
D)Memory loss
E)Loss of proprioception

Answer 1

C

Question 2

You are a scientist at a pharmaceutical company.You know that treating Parkinson's disease patients with dopamine has been ineffective in the past,however,your company has recently developed a method to modify drugs that can help them cross the blood-brain barrier.If you modified dopamine in this way,would it make dopamine treatment of Parkinson's more effective?

A)No,because acetylcholine is the main neurotransmitter that is deficient.
B)No,because injecting dopamine only makes the substantia nigra down-regulate its own production of dopamine.
C)No,because dopamine will be broken down in the body before reaching the brain.
D)Yes,a central issue with dopamine treatment is that dopamine cannot cross the blood-brain barrier.

Answer 2

D

Question 3

What are the symptoms of patients with cerebellar disease?

A)They cannot initiate movements,but will sit as though frozen for extended periods of time.
B)They have resting tremors,in which the head or limbs will continuously oscillate when no movement is intended.
C)They lose the ability to comprehend language,although they are still fully capable of speaking words.
D)All reflexes governing unconscious reactions to muscle stretch,muscle force,and nociceptor input are lost.
E)They cannot perform limb or eye movements smoothly,showing intention tremors that increase as a movement nears its final destination.

Answer 3

E

Question 4

Which of the following would occur if you touched a hot object with your right hand?

A)A stretch reflex would be triggered that would cause contraction of extensor muscles in the right arm.
B)A withdrawal reflex would be triggered by nociceptors that would stimulate contraction of flexor muscles in the right arm.
C)Reflex mechanisms would stimulate contraction of the extensor muscles of the right arm.
D)A withdrawal reflex would be triggered by stretch receptors that would inhibit contraction of extensor muscles of the right arm.
E)Nociceptors send pain information to the cerebral cortex,and descending activation of alpha motor neurons to extensor muscles would make you withdraw your right hand from the object. 

Question 5

According to the hierarchy of motor control,

A)the highest level of control consists entirely of neurons in the primary motor region of the cerebral cortex.
B)the middle level of control does not involve any areas of the cerebral cortex.
C)the local level of control includes the cerebellum and basal nuclei.
D)structures in the middle level receive information from both the higher and the local levels of the hierarchy.
E)afferent information from skin,joint,and muscle receptors cannot modify a movement once it has been initiated by a motor program from the middle level of the hierarchy.

Question 6

Your company wants to design a drug that inhibits unwanted motor contraction.Which is the best target for the drug?

A)The muscle fiber's motor neuron
B)Descending inputs at the middle level of the motor control hierarchy
C)The antagonistic muscle's fibers
D)Golgi tendon organs 
E)Interneurons in the local spinal cord region

Question 7

You are studying the electrical properties of a bicep muscle and find that when the arm is in a neutral position there is some degree of alpha motor neuron activity,but no other activity.You conclude

A)the bicep has muscle tone but is otherwise relaxed.
B)the bicep muscle is completely relaxed.
C)the bicep muscle is half contracted and carrying a light weight.
D)the bicep muscle is complete contracted.

Question 8

What is the function of the basal nuclei in normal motor control?

A)They provide a perceptual awareness related to specific sensory inputs from the eyes,nose,and mouth.
B)They provide a general perceptual awareness associated with somatosensory inputs from the skin,muscles,and joints.
C)They provide a sense of the cause-and-effect relationships between muscle actions and the consequences of taking these actions before executing them.
D)They participate in a looping neuronal circuit through which motor impulses are sent to facilitate or suppress movements.
E)They form an initial intention to move,such as when you decide to pick up an object.

Question 9

Which of the following does NOT describe the highest hierarchical level of motor control?

A)It creates a "motor program" that uses afferent information to generate a pattern of neural activity required to carry out a given action.
B)It involves brain regions that include the sensorimotor and cortical association areas.
C)It sends signals along "command neurons" to parts of the brain that make up the middle level of the motor control hierarchy.
D)It involves brain regions that function in memory,emotions,and motivation.
E)It initiates consciously planned movements.

Question 10

Which of the following normally occurs when a doctor's reflex hammer taps a patient's patellar tendon?

A)Alpha motor neurons stimulate contraction of intrafusal fibers in extensor muscles.
B)Alpha motor neurons stimulate contraction of extrafusal fibers in extensor muscles.
C)Alpha motor neurons that innervate ipsilateral flexor muscles are stimulated.
D)Inhibitory interneurons reduce action potential firing in alpha motor neurons to extrafusal fibers of extensor muscles.
E)Golgi tendon organs in the patellar tendon stimulate the contraction of extrafusal fibers of extensor muscles.

Question 11

Which best describes an event that occurs as part of the crossed-extensor reflex?

A)It stimulates contraction of the contralateral flexor and inhibits contraction of the contralateral extensor.
B)It stimulates contraction of the contralateral extensor and inhibits contraction of the contralateral flexor.
C)It is initiated by stretch in the ipsilateral extensor muscle.
D)Inhibitory interneurons are activated,which synapse onto contralateral extensor muscles.
E)Monosynaptic excitatory stimulation of ipsilateral extensor muscles occurs.

Question 12

Stretch reflexes

A)occur only in the legs.
B)inhibit antagonistic muscles.
C)mediate flexor activation and withdrawal from a painful stimulus.
D)are initiated by stimulation of Golgi tendon organs.
E)are initiated by stretching of extrafusal muscle fibers.

Question 13

What is the importance of reciprocal innervation in muscular reflexes?

A)It prevents simultaneous activity of antagonistic muscle groups that would impede limb movement. 
B)It ensures that limbs on the contralateral side of the body perform the same movements as those on the ipsilateral side.
C)It maintains signaling along afferent neurons from stretch receptors,even when a muscle shortens rapidly.
D)It prevents excessive force on a muscle from resulting in tearing of fibers,or damage to the tendon.
E)It recruits synergistic muscles to come to the aid of a muscle that help it generate force and limb motion.

Question 14

What is the function of Golgi tendon organs?

A)They detect stretch within tendons and inhibit the activation of alpha motor neurons to extrafusal muscle fibers in antagonistic muscles.
B)They detect painful stimuli within tendons and inhibit gamma motor neurons to intrafusal muscle fibers in muscles attached to those tendons.
C)They detect the angle of joints,and thus provide proprioceptive inputs about the position of the limbs in space.
D)They detect stretch within tendons and inhibit the activation of alpha motor neurons to extrafusal muscle fibers in the muscle attached to those tendons.
E)They stimulate the ends of intrafusal muscle fibers,ensuring that sensory information about muscle length is provided,even when a muscle shortens rapidly.

Question 15

What occurs when gamma motor neurons to a muscle are activated?

A)The muscle spindle goes slack.
B)The contractile ends of intrafusal fibers elongate.
C)The muscle lengthens.
D)Extrafusal muscle fibers within that muscle are inhibited from contracting.
E)Action potential firing increases in afferent neurons from the muscle spindles.

Question 16

Which is TRUE about the muscle fibers found in a muscle spindle?

A)They are not true muscle fibers because they cannot contract.
B)They are innervated by alpha motor neurons.
C)They function to maintain tension on spindle receptors.
D)When stimulated to fire,they always inhibit flexor muscles.
E)Their contraction is stimulated by alpha motor neurons and inhibited by gamma motor neurons.

Question 17

Intrafusal muscle fibers

A)are found in muscle spindles.
B)are innervated by alpha motor neurons.
C)generate most of the tension in a skeletal muscle.
D)fire continuously at a constant rate.
E)are only found in extensor muscles.

Question 18

You have an accident in an organic chemistry lab and end up with a novel compound.This compound,when fed to rats,appears to stimulate dopamine secretion from the substantia nigra.You decide to try to market the drug to humans as a therapy to treat ________.

A)nicotine addiction
B)vertigo 
C)Parkinson's disease
D)cerebellar disease
E)loss of voluntary motor movement following a stroke

Question 19

Which of the following statements is TRUE with regard to the motor control hierarchy?

A)The highest level of the hierarchy of motor control includes the frontal lobe cortex,the primary motor cortex,muscle sensory receptors,and the basal nuclei.
B)The highest level of the hierarchy of motor control is composed entirely of areas of cerebral cortex,and its main purpose is to create a conscious plan to move that depends on the initial position of the parts of the body in space.
C)Neurons of the middle level of the hierarchy integrate afferent information with signals from higher center command neurons to create a motor program-a pattern of neural activity required to properly perform a desired movement.
D)The local level of the motor control hierarchy includes the premotor and primary motor regions of the cerebral cortex,as well as the alpha motor neurons and muscle fibers themselves.
E)Reflexes that include local-level receptors and muscle fibers cannot occur without input from the higher centers of the motor control hierarchy.

Question 20

Ouch!  You accidentally touched a hot pan on the stove and pull your hand away quickly.Physiologically speaking,what just occurred?

A)An afferent neuron sent a signal in a monosynaptic reflex arc.
B)A nociceptor initiated muscle spindle fibers.
C)A nociceptor stimulated the local Golgi tendon organ.
D)A nociceptor stimulated contraction of the ipsilateral flexor muscle and inhibited contraction of the ipsilateral extensor muscle.
E)A nociceptor stimulated contraction of the contralateral flexor muscle and inhibits contraction of the contralateral extensor muscle.

Question 21

Which is TRUE about the function of the cerebellum?

A)It helps to coordinate body movements.
B)It is important in maintaining posture.
C)It receives input from sensory pathways.
D)It stores the memory of motor movements that involve several joints.
E)All of the choices are correct.

Question 22

Practicing a movement allows for "fine-tuning" the original program so that the movement can be executed with fewer corrections.

Question 23

You are a surgeon who is implanting a medical device in the brain of a patient with a persistent tremor in his right hand that obstructs his ability to write.Where do you implant the device that has been shown to dampen these tremors?

A)In the left corticospinal motor pathways because they control most fine,discrete muscle activity.
B)In the brainstem pathways because they control postural and most other coordinated body movements.
C)In the left somatosensory cortex because it initiates motor activity.
D)In the left corticospinal pathway or the left sensorimotor cortex that control movements of limbs on the right side of the body.

Question 24

Which best describes the specific cause of Parkinson's disease?

A)Enhanced sensitivity of cholinergic receptors to acetylcholine
B)Reduced ability of neurons in the substantia nigra to release dopamine
C)Failure of serotonin receptors to bind with these neurohormones
D)Hyperactivity of metabolic enzymes that degrade dopamine
E)Natural tendency of basal nuclei to follow a daily recurring,oscillating cycle of rising and falling norepinephrine release

Question 25

Afferent information about body movement is in part integrated at the level of the interneurons controlling the firing of alpha motor neurons.

Question 26

Which of the following is NOT true of corticospinal fibers?

A)They may synapse directly on alpha motor neurons.
B)They may synapse directly on gamma motor neurons.
C)They may synapse directly on interneurons.
D)They are collectively sometimes called the extrapyramidal system.
E)They may synapse with afferent neurons in ascending pathways.

Question 27

When a walking person lifts one foot off of the ground,which of these happens?

A)The body leans so that the center of gravity shifts over the foot that is lifted off the ground.
B)The body only accelerates forward,so the center of gravity remains directly between the two feet.
C)The body accelerates forward,but the center of gravity shifts over the foot that is lifted off the ground.
D)The body leans so that the center of gravity shifts over the foot that is on the ground.
E)The center of mass is left behind by the acceleration of the body,so the body must lean forward to compensate.

Question 28

During motor activity,alpha-gamma coactivation provides important information regarding muscle length to the higher motor control centers.

Question 29

What is the definition of "muscle tone"?

A)The resistance of muscle to continuous passive stretch
B)The sound made by a muscle at rest
C)The maximum contraction strength that a muscle is capable of
D)The tension in a muscle that is only due to the passive resistance of elastic structures
E)The average length of the muscle fibers in a given motor unit

Question 30

The corticospinal pathways

A)are descending motor pathways.
B)begin in the cortex of the cerebellum.
C)consist of many interneurons linked synaptically.
D)are composed of alpha motor neurons.
E)bring sensory information from the spinal cord to the somatosensory region of the cerebral cortex. 

Question 31

Afferent fibers from muscle spindle stretch receptors in a muscle make excitatory synaptic contact with motor neurons that innervate the extrafusal fibers of the same muscle.

Question 32

Inhibitory input to motor neurons is as important for normal muscle function as excitatory input.

Question 33

Information from the muscle spindle stretch receptors is not conveyed above the level of the spinal cord and thus does not reach consciousness.

Question 34

A young man is having trouble maintaining his posture after drinking too much at a party.The afferent pathways of the postural reflexes most likely affected in this man is the

A)cerebellum.
B)vestibular apparatus.
C)muscle spindles and temperature receptors.
D)nociceptors and chemoreceptors.
E)the somatosensory cortex.

Question 35

The motor neuron pool of a skeletal muscle consists of the neurons of all of the motor units of that muscle.

Question 36

Why do people with Parkinson's disease experience resting tremors?

A)Damage to the cerebellum alternately activates agonist/antagonist muscle pairs.
B)Excess glutamate is released in the premotor areas of the motor cortex.
C)Dopamine-secreting tumors directly activate alpha motor neurons.
D)Acetylcholinesterase at neuromuscular junctions is inactivated.
E)Activation of the sensorimotor cortex is reduced when the substantia nigra fails to deliver dopamine to the basal nuclei.

Question 37

Stimulation of a Golgi tendon organ causes a reflex contraction of the muscle whose tension the receptor is monitoring.

Question 38

Once a planned movement is under way,it is usually carried out with no further modifications until it is finished.

Question 39

The activity of alpha motor neurons innervating an extensor muscle can be inhibited by activation of the Golgi tendon organs in the tendon that attaches that muscle to bone.

Question 40

Which of the following symptoms is common following damage to the cerebellum?

A)Flaccid paralysis
B)Violent,uncontrolled body movements called chorea
C)Intention tremors
D)Resting tremors
E)Spastic paralysis

Question 41

As you learn to perfect your tennis serve,your brain is comparing the muscle contraction program for the tennis serve with the actual movement as it occurs and making adjustments in the movements.This activity is primarily occurring in your cerebellum.

Question 42

In general,the brainstem descending pathways have greater influence over motor neurons controlling muscles involved in fine movements and the corticospinal pathways are more involved in the coordination of large muscle groups and postural muscles.

Question 43

Which of the following functions are controlled by the higher centers in the motor control hierarchy?

A)Forming a complex plan of footsteps while learning salsa dancing
B)Trying to remember the motions involved in writing the second character in the Chinese alphabet
C)Specifying tension of specific muscles involved in a soccer kick
D)Comparing muscle contraction program with the initial plan while mastering a golf swing
E)None of these functions are controlled by higher centers.

Question 44

When a person steps on a piece of glass with their right foot,flexor muscles on the left leg and extensor muscles on the right leg will be stimulated to contract.

Question 45

Motor pathways extending from the central nervous system to muscle fibers are subject to control by both excitatory and inhibitory interneurons.

Question 46

Crossed-extensor reflexes,but not stretch reflexes,are important postural reflexes.

Question 47

You are a neurosurgeon mapping a patient's primary motor cortex.You know that the region dedicated to the quadriceps muscles will be larger than the region dedicated to the hand muscle because the quadriceps are larger than the hand muscles.

Question 48

Motor neurons that innervate skeletal muscle fibers are subject to the summative effects of interneurons that release excitatory neurotransmitters and interneurons that release inhibitory neurotransmitters.

Question 49

Sensory neurons that are part of the stretch reflex synapse directly onto the motor neurons of antagonist muscles,and inhibit them.

Question 50

Which of these pathways involves brain structures?

A)The corticospinal pathway
B)The extrapyramidal system
C)The Golgi tendon organs
D)The knee-jerk reflex
E)All of these

Question 51

You are a neurosurgeon exploring a patient's right primary motor cortex during awake brain surgery.As you stimulate various areas,you are asking the operating room nurses to watch for the resulting muscle contractions on the left side of the patient's body.

Question 52

The thalamus is an important relay station for feedback of information to the basal nuclei from the motor cortex.

Question 53

Which is TRUE about reflexes initiated by muscle spindle activation?

A)They have a monosynaptic component.
B)They result in activation of gamma motor neurons.
C)They result in activation of extrafusal muscle fibers.
D)The "knee-jerk" reflex is an example.
E)They inhibit the activation of muscles that are stretched.