Chapter 10 smartbook Q's

Most stretch reflexes are examples of Blank______ feedback loops.

negative

In addition to making synapses on motor neurons, descending neurons of the corticospinal and brainstem pathways make synapses on _____

1.) central terminals of afferent neurons 2.)interneurons in ascending sensory pathways

Stretching a skeletal muscle causes a(n) ______ in the tension on its tendon, which in turn ______ the Golgi tendon organs, which in turn via a spinal reflex causes ______ of the muscle.

1.)increase 2.) activates 3.)inhibition

An apparatus consisting of peripheral endings of afferent nerve fibers wrapped around modified muscle fibers, several of which are enclosed in a connective tissue capsule, is called a(n)

muscle spindle

The nervous system receives information about the length of a muscle from the

muscle spindle apparatus

A collection of cell bodies in the central nervous system is called a

nucleus

In the brain, an aggregation of neuron cell bodies is called a(n)

nucleus

Abnormally increased resistance that occurs when a joint is moved passively at high speeds is called

hypertonia

After originating in one side of the cortex, most corticospinal tracts descend on the Blank______ side of the spinal cord.

opposite

A reflex arc that is initiated by a painful stimulus, such as touching something very hot, is called a(n) Blank______ reflex.

withdrawl

Which three locations contain sensory receptors that send input to local interneurons that control a given skeletal muscle?

* Within other nearby muscles, such as those with antagonistic actions *Within the skeletal muscles controlled by the motor neurons *In the tendons, joints, and skin of body parts affected by actions of the muscle

Neurons in the corticospinal and brainstem pathways synapse on

*alpha motor neurons *gamma motor neurons *spinal cord interneurons

Middle-level structures of the motor control hierarchy include which of the following?

*cerebellum and thalamus *basal nuclei and brainstem *sensorimotor cortex

The general intention of any movement is determined by neurons that originate in the ______

*sensorimotor cortex *areas of the brain involved in memory, emotions, and motivations

Which of the following are considered to be part of the "sensorimotor cortex?"

1.) Supplementary motor cortex 2.) Premotor area 3.) Somatosensory cortex 4.) Parietal-lobe association cortex

The following statements pertain to brainstem pathways. Which ones are true?

1.) They are often referred to as the extrapyramidal system. 2.)They provide input to the local level of the motor control hierarchy. 3.)They are often referred to as indirect pathways.

Some of the fibers of the descending pathways affect afferent systems. They do this via (1) presynaptic synapses on the terminals of afferent neurons as these fibers enter the _____ ____ system or (2) synapses on _____in the ascending pathways.

1.) central nervous system 2.) interneurons

Neurons in the middle level of the motor control hierarchy receive input from the _____ neurons, and simultaneously receive afferent information from receptors in the muscles, tendons, joints, and skin, as well as from the ______apparatus and eyes.

1.) command 2.) vestibular

The basal nuclei Blank______

1.) facilitate some movements and inhibit others 2.)are components of circuits that plan and monitor movements

The building blocks for all movements are motor units, each comprising one motor ______ together with all the ______ muscle fibers that it innervates

1.) neuron 2.)skeletal

Activation of Golgi tendon organs ____

1.) occurs in response to muscle tension 2.)stimulates excitatory pathways via interneurons in the spinal cord, increasing tension in antagonistic muscles 3.) stimulates inhibitory pathways via interneurons in the spinal cord, decreasing tension in the attached muscle

Muscle spasms and muscle cramps ___

1.) result from dysfunction of muscle and not nervous tissue 2.)are forms of hypertonia

Two major reflex pathways involved in maintenance of upright posture are ____ reflexes and crossed- ____ reflexes

1.) stretch 2.)crossed - extensor reflexes

Put the steps of the monosynaptic knee-jerk reflex in the correct order from stimulus (top) to muscle contraction (bottom).

1.) stretching of the spindle fibers of a muscle 2.)distorting of central bag or chain region 3.)stimulus of sensory neurons 4.)AP travel to spinal cord via sensory neuron 5.)somatic motor neuron stimulated 6.)contraction of extrafusal fibers stimulated

Which of the following statements about hypertonia are true?

1.)Caused by an abnormally high alpha motor neuron activity 2.)Usually associated with dysfunction of the descending pathways that normally inhibit motor neurons

Which of the following statements are true regarding muscle tone?

1.)Is due in part to alpha motor neuron activity 2.)Is due in part to the elastic properties of muscles and joints

Which two of these are most helpful in maintaining upright posture and balance?

1.)Muscle crossed-extensor reflexes 2.)Muscle stretch reflexes

Which two are the main determinants of resting skeletal muscle tone?

1.)Ongoing alpha motor neuron activity 2.)Passive elastic properties of muscles and joints

Which of the following statements about neurons of the corticospinal tracts are true?

1.)Terminate in the spinal cord 2.)Originate in the sensorimotor cortex 3.)Pass along the ventral surface of the medulla oblongata

During walking, when the extensor muscles are activated in the leg supporting the body's weight, which of the following simultaneously occurs?

Contralateral extensor muscles and ipsilateral flexor muscles are inhibited.

Higher centers of the brain, also known as "command" neurons, include ----areas involved with memory, emotions, and motivation.

Cortical and subcortical

Which of the following statements is true about this figure of muscle action?

Passive stretch of the muscle by an external load activates the spindle stretch receptors and causes an increased rate of action potentials in the afferent nerve.

The cerebellum receives information from which of the following?

Sensorimotor cortex Muscles Eyes Tendons Vestibular system

Which of these play a prominent role in establishing the programs that determine the specific sequence of movements needed to accomplish a desired action?

The brainstem and subcortical nuclei

To rapidly adjust motor unit activity to unexpected obstacles to movement or to painful stimuli, the local level of the motor control hierarchy relies on inputs from _____

afferent fibers from sensory receptors

Which of the following mechanisms ensures that muscle spindle stretch receptors continue to provide information on muscle length even when a contracting muscle shortens?

alpha-gamma coactivation

______ is also known as Lou Gehrig's disease.

amyotrophic lateral sclerosis

Looping parallel circuits that begin in and return to the sensorimotor cortex through the ______ and the thalamus facilitate some movements and inhibit others.

basal nuclei

Extrapyramidal tracts originate in the

brainstem

What structure receives information from the sensorimotor cortex, the vestibular system, eyes, skin, muscles, joints, and tendons, and provides timing signals that coordinate execution of complex movements involving several joints?

cerebellum

The two major descending motor pathways are called the

corticospinal and brainstem pathways

Prolonged and painful involuntary muscle contractions are called

cramps

Action potentials from muscle spindle stretch receptors Blank______ frequency as a result of increasing muscle lengths.

decrease in

The basal nuclei are located

deep in the cerebral hemispheres, lateral to the thalamus

The subcortical and brain stem nuclei play a major role in

executive functions such as planning and monitoring

The category of skeletal muscle fibers that are NOT part of the muscle spindle and which constitute the greatest mass and generate the force and movement of the muscle are called

extrafusal

The skeletal muscle fibers that generate the force and movement of muscles are the Blank______ fibers

extrafusal

The skeletal muscle fibers that generate the force and movement of muscles are the Blank______ fibers.

extrafusal

True or false: Afferent fibers that impinge on local interneurons controlling a muscle originate from sensory receptors found: 1. in the muscle being controlled, 2. in nearby muscles, such as those with antagonistic actions, and 3. in the vestibular apparatus of the inner ear.

false

During muscle shortening, tension and stretch in the central region of an intrafusal fiber is maintained by action potentials in Blank______.

gamma motor neurons

Muscle tone is ______ when there is greater activity in alpha motor neurons to a muscle.

increased

What is the stimulus for Golgi tendon organs?

increased tension on the tendon

Action potential firing in gamma motor neurons

increases the sensitivity of a muscle to stretch

When Golgi tendon organs are stimulated, contraction of the associated muscle is

inhibited

Intrafusal muscle fibers are those that form ____ of the muscle spindle

inside

Modified skeletal muscle fibers within a muscle spindle apparatus are called________ _______

intrafusal muscle

The terms reflex, unconscious, and automatic often serve as synonyms for

involuntary

are motor reflexes involuntary or voluntary?

involuntary

Which level of the motor control hierarchy makes adjustments in response to unexpected obstacles to movement and to painful stimuli in the environment?

local level

When neurons of the descending pathways synapse on interneurons in the brainstem and spinal cord, the effect on alpha motor neurons_____

may be excitatory or inhibitory

Consider the case of a sensory neuron stimulating a motor neuron and an interneuron leading to contraction of the agonist muscle and inhibition of the antagonistic muscle group. This phenomenon is called

reciprocal innervation

All areas of the cerebral cortex that play a role in the control of skeletal muscle are referred to as the Blank______.

sensorimotor cortex

The middle level of the motor control hierarchy ____

specifies the individual postures and movements of muscles that are needed to carry out an intended action

Planning and monitoring motor movements and learning of skilled movements is a function of Blank______.

subcortical and brainstem nuclei

Different muscles which, when contracting, cause the same movement around a joint (for example flexion of the elbow) are referred to as Blank______ muscles.

synergistic

Golgi tendon organs monitor what?

tension

Which of the following muscle reflexes is a monosynaptic reflex?

the stretch reflex

Neurons in the brain that contribute axons to descending motor tracts and act as facilitators and inhibitors to lower motor neurons are called

upper motor neurons