Motor Speech Disorders Quiz 2

The motor system is responsible for

all motor activity involving striated muscle

The motor system is essential to

normal reflexes, maintaining normal muscle tone and posture, and to the planning, control, and execution of voluntary movement, including speech

The motor system allows

thought to be turned into movement

The motor system is

extremely complex

The type of motor speech disorder is dependent on

the location and extent of damage to the motor system

Central nervous system (CNS)

brain and spinal cord

Peripheral nervous system (PNS)

-12 pairs of cranial nerves and their ganglia

-31 pairs of spinal nerves and their ganglia

12 pairs of cranial nerves and their ganglia

-project from the cranium (inside the skull)

-innervate head, neck, thorax, abdomen

31 pairs of spinal nerves and their ganglia

-project from spinal cord

-innervate chest, arms, legs

Nearly all activity in nervous sytem orginates in or is processed by

the brain

Voluntary motor commands to muscles originate in

the brain

The brain receives

sesnory information from the body

The brain controls

cognitive functions

The brain is divided into

cerebrum, brainstem, cerebellum

Outer part of cerebrum is

cortex

The largest and most prominent part of brain

cerebrum

The cerebrum is split into two hemispheres by

longitudinal fissure (corpus callosum)

The cerebrum is organized into four lobes

frontal lobe, temporal lobe, parietal lobe, occipital lobe

Another name for fissure

sulcus

Most obvious feature of the cerebrum

the deep convolutions known as gyri

Prominent sulci in the cerebrum

lateral sulcus and central sulcus

Prominent gyri in the cerebrum

precentral gyrus and postcentral gyrus

Precentral gyrus

primary motor cortex, motor strip

Postcentral gyrus

primary sensory cortex, sensory strip

The surface of the cerebrum is

cerebral cortex

Cerebral cortex is described as

"gray matter" of brain

The cerebral cortex performs ___________ ___________ activites

higher cognitive

Higher cognitive activity examples

language, motor planning, problem solving, sensory perception

Deeper "white matter" gets its color from

myelin

Purpose of myelin

speeds traveling of electrical impulses

Brainstem is divided from

top to bottom

Parts of brainstem

midbrain, pons, medulla oblongata

Brainstem is located

between cerebrum and spinal cord

Cranial nerve nuclei

points where cranial nerves attach to brainstem

Start of peripheral nervous system

cranial nerve nuclei

Automatic reflexes come from

the brainstem

The brainstem acts as a passageway for

descending and ascending neural tracts that travel between cerebrum and spinal cord

The brainstem controls

certain integrative and reflexive actions (respiration, consciousness)

The brainstem conveys

motor impulses from CNS to muscles of larynx, face, tongue, pharynx, and velum

Cranial nerves project out from

CNS

True or false: Things like reflexes may still occur if someone has no function in the brain

true

Damage to cerebellum causes

disorganized speech

The most important function of the cerebellum

coordinates voluntary movements so muscles contract with correct amount of force and at appropriate times

The cerebellum is attached to

the back of the brainstem

The cerebellum makes neural connections with

cerebral cortex and many other parts of CNS

Supratentorial Level

includes hemispheres including basal ganglia, thalamus, CNs I and II

MSDs that occur at the supratentorial level

-apraxia of speech

-dysarthria (spastic, unilateral UMN, hypokinetic, hyperkinetic)

Posterior Fossa

includes brainstem (pons, medulla, midbrain) and cerebellum, origins of CNs III-XII

MSDs that occur when there is damage to the posterior fossa

-dysarthria (spastic, unilateral UMN, hyperkinetic, ataxic, flaccid)

Apraxia of speech is more common when

damage is in the left hemisphere

Basic functional unit of the nervous system

neuron

Neurons are responsible for

receipt, transmission, and processing of information through electrochemical activities to other neurons

Basic components of the neuron

cell body, dendrites, axons, myelin, synapse

Cell body

gray in color; central processing unit responsible for neuronal metabolic functions

Dendrites

receives neural stimuli from other neurons or from sensory organs, shorter and more numerous projections of the nerve cell

Axons

conducts nerve impulses away from the neuron to muscles, glands or other neurons; longer single fiber (only one per nerve cell)

Boutons

allow an axon to communicate with many dendrites

Myelin

composed of Schwann cells, which enhances rapid transmission of electrical impulse along nerve fiber

Synapse

juncture point at which electrical impulses are transmitted from nerve to muscle, gland, or another neuron

Motor neurons

cause muscle contractions (movement)

Sensory neurons

(also known as afferent neurons) are specialized nerve cells that convert external and internal environmental stimuli—such as touch, light, sound, and pain—into electrical impulses

Interneurons

most common type; link neurons to other neurons; control movement

Efferent neurons

send impulses away from the CNS; motor neurons in general

Afferent neurons

send impulses toward the CNS; sensory neurons in general

glial cells

other nervous system cells

Oligodendroglia

produce myelin in the CNS

Schwann cells

produce myelin in the PNS

Microglia

travel to site of lesion and engulf cellular debris before removing it ("clean up crew")

Astrocytes

-form connective tissue in the CNS

-lining around the surface of the brain and blood vessels

-scars around dead brain tissue

Tracts

groups of axons that travel together in the nervous sytem; related in function

Bundles within the CNS are

tracts

Bundles within the PNS are

nerves

CNS tracts transmit impulses to

other neurons

Peripheral nerves orignate in

CNS but then travel to peripheral end organs in PNS

Peripheral nerves can regenerate if

cell body survives

Small electrical charge is conducted along

an axon

Neurotransmitters are released from the

terminal ramification (or end)

Transmitter crosses gap (synaptic cleft) between

active neuron and adjoining neurons

If enough excitatory transmitters are received

an impulse is generated in the receiving cell

If too much inhibitory neurotransmitter in the receiving neuron

impulse will not be transmitted

Neurotransmitters found in

synaptic cleft

Glutamate

primary excitatory neurotransmitter within CNS

Gamma-aminobutyric acid (GABA)

primary inhibitory neurotransmitter that regulates muscle tone

Dopamine

-influences movement, cognition and learning

-aids in initiation and control of skilled motor acts

-learning, attention, mood, sleep, motivation

Loss of dopamine is common in

patients with dementia

Acetycholine

-involved with PNS

-influences neuronal excitability for motor speech

-induces contraction of muscle fibers

Two important points about neural impulses

-a single neuron may have synaptic connections with many different axons simultaneously (several thousand), some excitatory, some inhibitory

-The receiving neuron only fires when it reaches threshold of excitatory transmitters

Many types of malfunctions with neurotransmitters including

-too much

-too little

-poor uptake

Associated disorders with abnromalities of neurotransmitters

-Parkinson's disease (dopamine)

-Myasthenia gravis (acetylocholine)

-Cerebral Palsy (GABA)

The association cortex is largely responsible for

the desire to move

Primary cortex

analyzes a single type of neural input

Primary cortex is comprises of

-cortices that first analyze sensory information (primary auditory cortex, primary visual cortex, primary sensory cortex)

-cortex that receives planned motor impulses from cortical and subcortical areas of the brain (primary motor cortex)

Planning for voluntary movement originates in the

association cortex, not the motor cortex

Movement always begins in

the association cortex

Association cortex

makes sense of sensory impulses initially analyzed by primary cortices

The association cortex is not a single region of the brain, but is divided into what four areas of cortex

-temporal

-parietal

-frontal

-occipital

The association cortex formulates

initial planning of a voluntary movement

The association cortex sends

rough sequence of motor impulses down to subcortical structures for further processing and refining

The temporal association area is

the upper part of the temporal lobe

The upper part of the temporal lobe deals with

-recognition of complex visual stimuli

-integrating auditory stimuli with other areas of the brain

-formation of memories