Nervous System: Speech

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Nervous SystemSpeech

• Perry C. Hanavan, Au.D.

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The nervous system is important for moment and
speech

• Movement
• respiration
• phonation
• articulation
• all aspects of
• speech production
• speech perception

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The nervous system divisions

• CNS
• brain and spinal cord
• glial cells
• astrocytes
• oligodendrocytes
• forms myelin

• PNS
• cranial nerves and spinal nerve
• Schwann cells
• forms myelin

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There are various ways of organizing the function
and anatomy
CNS Cerebrum (cortex, basal nuclei, thalamus,
hypothalamus) (parietal, temporal, frontal,
occipital limbic lobes) Midbrain Brainstem (pons,
brainstem) Cerebellum
PNS
Cranial Nerves
Somatic Afferent Efferent
Autonomic Sympathetic Parasympathetic
Spinal Cord
Cervical Nerves
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Functional divisions

• Somatic nervous system voluntary, controls
  skeletal muscle
• Autonomic nervous system involuntary, controls
  smooth muscle

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The neuron is the basic unit of the nervous system

• dendrites
• cell body
• axon
• terminal buutons
• synapse
• myelin
• nodes of Ranvier
• neurotransmitters

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There are various classifications of neurons.

• Number of Processes
• unipolar
• bipolarspiral ganglion of auditory nerve
• multipolar
• Golgi Type Iinnervate muscles or
  glands--myelinated
• Golgi Type IIinnervate nearby neurons in
  cns--unmyelinated
• Function
• Afferenttowards cns from sensor
• Efferenttowards muscle or gland from CNS
• Interneuronsbetween neurons
• Neurotransmitters
• Dopaminergic--dapamine
• Cholinergic--acetylcholine
• Serotonergic--serotonin

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There are various types of sensory receptors
involved in speech

• Teleceptors distance eyes, cochlea
• Exteroceptors near skin
• Proprioceptors position in space semicircular
  canals
• muscles, tendons, joints
• Visceroceptors viscera visceral structures
• Mechanoreceptors pressure tissue
• Thermoceptors temperature
• Nocioreceptors tissue damage tissue
• Photoreceptors light retina
• Chemoreceptors taste, smell tongue, nose
• Baroreceptors air pressure trachea, bronchi

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Cerebralspinal fluid serves a number of functions

• Meningessurrounds brain and spinal cord
• Ventriclesfour csf filled cavities filled within
  brain
• Cerebral spinal fluid is produced by choroid
  plexis cells in ventricles
• composed of proteins and glucose, lymphocytes
• circulates throughout meninges and ventricles
• protects from traumashock absorbing
• provides buoyancy in fluid to lighten weight of
  brain

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Cortex is the outer grey matter located in the
cerebrum of the brain

• Unmyelinated primary sensory, motor, association
  and limbic areas
• Irregular shaped portion consisting convolutions
• gyriraised surfaces
• sulcishallow depressions
• fissuredeep depressions
• longitudinaldivides hemispheres
• lateralsuperior, inferior division
• central sulcusanterior, posterior

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Matter
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The lobes of the brain have important functions

• frontalreasoning, problem solving, personality,
  speech and language production
• motor strip
• Brocas areaspeech production
• parietalsomatosensory (touch, pain,
  proprioception, temperatures)
• sensory strip
• angular gyrus
• supramarginal gyrus
• temporalunderstanding
• auditory cortex
• Wernickes area
• occipitalreception and processing of visual
  information
• limbichippocampus, amygdala, and medial margins
  of the temporal, parietal, and frontal lobes that
  function for emotions, sexual function,
  temperature regulation and feeding behavior

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Lobes of the brain
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Cerebral Cortex

• Frontal Lobe- associated with reasoning,
  planning, parts of speech, movement, emotions,
  and problem solving
• Parietal Lobe- associated with movement,
  orientation, recognition, perception of stimuli
• Occipital Lobe- associated with visual processing
  
• Temporal Lobe- associated with perception and
  recognition of auditory stimuli, memory, and
  speech

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Motor Strip
Motor Cortex Motor Cortex Motor Cortex
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Cortical connections play a fundamental role in
the brain

• commisureslinks the twp hemispheres of brain
  (right and left)
• corpus callosum
• association fiberslink cerebral areas of brain
  in same hemisphere
• arcuate fasciculi
• projection fiberslinks grey matter with other
  regions of the brain
• internal capsule

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Neuro-speech-language
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Subcortical areas of the brain play a primary
role in motor function

• basal ganglia/nuclei
• caudate nucleus, putamen and globus pallidus.

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Ventricles of the Brain

• Ventricles

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Basal Nuclei

• Control voluntary movements and establishing
  postures. When they are altered - as in disorders
  Huntington or Wilson disease - unwanted
  movements, such as involuntary jerking movements
  of an arm or leg or spasmodic movement of facial
  muscles.
• The caudate nucleus, putamen and anterior limb of
  the internal capsule are collectively known as
  the corpus striatum (i.e. striated body) based on
  appearance.
• Similarly, the shape of the putamen and globus
  pallidus resembles a lens, and collectively
  called the lenticular nucleus.

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The thalamus processes and transmits to and from
cortical areas

• A large mass of gray matter deeply situated in
  the forebrain. There is one on either side of the
  midline.
• Relays to the cerebral cortex information
  received from diverse brain regions--a requisite
  'last pit stop' for information going to cortex.
• Axons from every sensory system (except
  olfaction) synapse here as the last relay site
  before the information reaches the cerebral
  cortex.
• There are other thalamic nuclei that receive
  input from cerebellar-, basal ganglia- and
  limbic-related brain regions.

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Limbic System

• Limbic System

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Midbrain

• A rostral part of the brainstem if impaired in
  its core (i.e. the tegmentum), results in loss of
  consciousness or coma, because it contains the
  rostral end of the reticular formation.
• The dorsal or posterior part has the superior
  colliculus, which is important for visual system
  reflexes, and the inferior colliculus, which is
  important for auditory system function.
• The ventral or anterior part has the cerebral
  peduncle, which is a huge bundle of axons
  traveling from the cerebral cortex into/ through
  the brainstem those fibers are important for
  voluntary motor function.
• Two other structures in the depth of the midbrain
  that are important for normal motor function are
  the red nucleus (not visible) and the substantia
  nigra.

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Brainstem

• Anatomy
• Midbrain
• Pons
• Medulla
• Function
• Alertness
• Arousal
• Breathing
• Blood Pressure
• Most of the Cranial Nerves
• Digestion
• Heart Rate
• Other Autonomic Functions
• Relays information between the Peripheral Nerves
  and Spinal Cord to the Upper Parts of the Brain

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Cranial Nerves

• CN V Trigeminal
• Sensory
• Touch, pressure, pain, proprioception, and
  temperature from various areas of the face
• Upper lip, teeth, upper oral cavity, lower lip
  and teeth, lower jaw and oral cavity
• Motor
• Muscles of mastication and some extrinsic
  laryngeal muscles
• Tensor veli palatini muscle
• Tensor tympani muscle

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Cranial Nerves

• CN VII Facial
• Motor
• Muscles of facial expression extrinsic laryngeal
  muscles, and stapedius.
• Parasympathetic innervation of the lacrimal,
  submandibular, and sublingual glands (salivary
  glands), as well as mucous membranes of
  nasopharynx, hard and soft palate.
• Sensory
• Taste sensation from anterior 2/3 of tongue hard
  and soft palates.
• General sensation from the skin of the concha of
  the external ear and from a small area behind the
  ear.

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Cranial Nerves

• CN VIII Auditory/Vestibular
• Vestibular
• Balancerotary and linear
• Auditory
• Sound

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Cranial Nerves

• CN IX Glossopharyngeal
• Sensory
• Taste from the posterior one-third of the tongue
• Sensations of pain, touch, and temperature from
  external ear, Eustachian tube, tonsils, pharynx,
  posterior one-third of tongue, and pharynx
• Motor
• Involved in swallowing (pharyngeal muscles)
• Salivary glands

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Cranial Nerves

• CN X - Vagus
• Motor
• Soft palate, pharynx, and larynx
• Phonation (pharyngeal, superior laryngeal and
  recurrent laryngeal nerves)
• Heart, thoracic, and abdominal smooth muscles,
  glands
• Sensory
• Thoracic and abdominal viscera, larynx, pharynx,
  trachea, esophagus
• Taste buds around epiglottis
• External ear canal

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Cranial Nerves

• CN XII Hypoglossal
• Motor
• Intrinsic and extrinsic muscles of tongue,
  extrinsic laryngeal muscles
• Sensory
• The pharyngeal phase of swallowing is monitored
  by hypoglossal nerve

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Vascular
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Vascular