Csd 210 anatomy & physiology of the speech mechanism ii


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  • Alveolar ridge starts the hard palate. Continues through bony structure. Soft palate begins where bony structure ends and continues through uvula.
  • Red. Most critical for speech.
  • Myelination- fatty tissue
  • Csd 210 anatomy & physiology of the speech mechanism ii

    1. 1. Anatomy & Physiology of the Speech Mechanism II COMSDIS 210: Survey of Communication Disorders
    2. 2. Summary How is speech produced? <ul><li>1. A person inhales and then exhales air. The exhaled air is sent upward through the larynx, where it passes through the vocal folds. </li></ul><ul><li>2. As the air passes through the vocal folds, they are set into rapid vibration, which transforms the air into sound. (Sounds like a “buzz”.) </li></ul>
    3. 3. <ul><li>3. The sound is modified by the shape and configuration of an individual’s vocal tract. </li></ul><ul><li> (particularly the oral and nasal cavities) </li></ul><ul><li>4. The sound is shaped into specific speech sounds created by manipulations of the speech articulators. </li></ul>
    4. 4. Modification of the sound <ul><li>The vocal tract is an acoustic resonator. It modifies the quality of sound produced by the larynx. </li></ul><ul><li>Each sound has a fundamental frequency and harmonics. </li></ul><ul><ul><li>FF = lowest frequency component directly related to </li></ul></ul><ul><ul><li>speech at which vf are opening and closing) </li></ul></ul><ul><ul><li>Harmonics (whole number multiples of the FF) </li></ul></ul><ul><li>Depending upon the physical characteristics of the resonator (vocal tract) some frequencies will be attenuated (reduced) and some will be enhanced. </li></ul>
    5. 5. Resonance <ul><li>Resonation : modification of the glottal tone, through the attenuation and enhancement of its frequencies, as the sound moves through the pharyngeal tract (laryngopharynx, oropharynx, nasopharynx). </li></ul><ul><li>Every persons pharyngeal tract is shaped differently which creates individual variation. </li></ul><ul><li>Adds to the “fullness” and “richness” of the sound </li></ul>
    6. 6. Shaping of speech sounds <ul><li>The sound is further shaped by modifications of the articulators. </li></ul><ul><li>Articulators include: lips, tongue , teeth, hard palate and soft palate (velum). </li></ul><ul><li>Movements of the mandible (lower jaw) and maxilla (upper jaw) aid in shaping of individual speech sounds (the process of articulation ). </li></ul><ul><li>Figure 3.6, p. 93 </li></ul>
    7. 7. <ul><li>The larynx is also an articulator. </li></ul><ul><ul><li>Responsible for “voiced” versus “voiceless sounds”. </li></ul></ul><ul><ul><li>Cognates : two sounds that are produced exactly the same way and differ only by voicing. </li></ul></ul>
    8. 8. Speech and language activity is controlled by brain <ul><li>Neuroanatomy: structures associated with the human nervous system. </li></ul><ul><li>Neurophysiology: function of the structures associated with the human nervous system. </li></ul>
    9. 9. The 2 major nervous systems of the human body <ul><li>Central Nervous System (CNS) </li></ul><ul><ul><li>Brain </li></ul></ul><ul><ul><li>Spinal cord </li></ul></ul><ul><li>Peripheral Nervous System (PNS) </li></ul><ul><ul><li>The nerves that emerge from the brain and spinal cord to innervate the rest of the body. </li></ul></ul>
    10. 10. Peripheral nerves <ul><li>Carry info back and forth between the brain, spinal cord and rest of body </li></ul><ul><li>Cranial nerves (emerge from the brain) </li></ul><ul><ul><li>12 pairs of cranial nerves </li></ul></ul><ul><ul><li>Run between brain stem and face/neck </li></ul></ul><ul><ul><li>Impt. For speech, language, hearing & swallowing </li></ul></ul><ul><li>Spinal nerves (emerge from the spinal cord) </li></ul><ul><ul><li>31 pairs of spinal nerves </li></ul></ul><ul><ul><li>Run between spinal cord and peripheral areas of body </li></ul></ul><ul><ul><li>Impt. For reflexes and voluntary sensory, motor activity </li></ul></ul>
    11. 11. P. 93 (List of cranial nerves) <ul><li>I (Olfactory) VII (Facial) </li></ul><ul><li>II (Optic) VIII (Acoustic) </li></ul><ul><li>III (Oculomotor) IX (Glossopharyngeal) </li></ul><ul><li>IV (Trochlear) X (Vagus) </li></ul><ul><li>V (Trigeminal) XI (Accessory) </li></ul><ul><li>VI (Abducens) XII (Hypoglossal) </li></ul>
    12. 12. Neurons and neurotransmission <ul><li>Neuron: the cells making up the nervous system that also carry the sensory and motor information. </li></ul><ul><ul><li>Most covered in myelin (sheath of coating) </li></ul></ul><ul><ul><ul><li>Protects the neuron </li></ul></ul></ul><ul><ul><ul><li>Contributes to the rapid relay of nerve impulses </li></ul></ul></ul><ul><li>Myelination: growth of the myelin sheath (begins in utero but not complete until late childhood) </li></ul><ul><li>Demyleination: loss of myelin; results in malfunctioning of the nerve cells; many different symptoms </li></ul>
    13. 13. <ul><li>Neurons composed of a cell body and two extensions. </li></ul><ul><li>The extensions receive and transmit information to and from the cell body in the form of electrical-chemical nerve impulses </li></ul><ul><li>Axons: take nerve impulses away from the cell body (efferent extensions) </li></ul><ul><li>Dendrites: take nerve impulses into the cell body (afferent extensions) </li></ul>
    14. 14. Figure 3.2, p. 84 <ul><li>Impulses move from one neuron to another by traveling down one’s dendrite and into its cell body and then along the axon to another neuron’s dendrite. </li></ul><ul><li>Synapse: space where two neurons meet. (Impulse must cross the synapse) </li></ul><ul><li>Neurotransmitters (chemical agents helping to carry info across the synaptic cleft). </li></ul>
    15. 15. 3 major divisions of the brain <ul><li>Brain stem </li></ul><ul><li>Cerebellum </li></ul><ul><li>Cerebrum (cerebral cortex) </li></ul>
    16. 16. Brain stem <ul><li>Sits on top of the spinal cord. Is the conduit between the rest of the brain and the spinal cord. </li></ul><ul><li>Includes 3 major reflex centers: cardiac (heart), vasomotor center (blood vessels) and respiratory center (breathing). Regulates breathing and blood circulation; affects level of consciousness. </li></ul><ul><li>Also controls visual and auditory reflexes via nerves supplying the face and head. </li></ul>
    17. 17. Cerebellum <ul><li>Sits posterior to the brain stem. </li></ul><ul><li>Regulates motor and muscular activity. </li></ul><ul><ul><li>Coordination of movements </li></ul></ul><ul><ul><li>Muscle tone </li></ul></ul><ul><ul><li>Strength and range of motion </li></ul></ul><ul><ul><li>Posture and equilibrium </li></ul></ul><ul><li>Linked to higher-order cognitive functions. </li></ul>
    18. 18. Cerebrum (Cerebral cortex) <ul><li>Largest of the 3 major divisions </li></ul><ul><li>Controls thinking, problem solving, planning, creating and rationalizing </li></ul><ul><li>Consists of 2 hemispheres (left and right) separated by a long crevice ( longitudinal fissure ). </li></ul>
    19. 19. <ul><li>The 2 hemispheres need to communicate with each other. The corpus callosum (band of fibers connecting the hemispheres) enables communication between the 2 hemispheres. </li></ul><ul><ul><li>Figure 3.3, p. 86 </li></ul></ul>
    20. 20. The cerebrum’s 4 lobes Figure 3.4, p. 87 <ul><li>Each represented in both hemispheres </li></ul><ul><li>Frontal lobe </li></ul><ul><li>Temporal lobe </li></ul><ul><li>Parietal lobe </li></ul><ul><li>Occipital lobe </li></ul>
    21. 21. Frontal lobe <ul><li>Largest lobe; sits in the most anterior part of the brain. </li></ul><ul><li>2 primary functions: </li></ul><ul><ul><li>Activates/controls fine and complex motor activities including speech </li></ul></ul><ul><ul><li>Controls executive functions (problem solving, organizing, planning, creating, reasoning, decision making, social awareness and rationalizing) </li></ul></ul><ul><ul><ul><li>In prefrontal cortex </li></ul></ul></ul>
    22. 22. Frontal lobe (continued) <ul><li>Houses “ Broca’s area ” </li></ul><ul><li>Important region for speech and language </li></ul><ul><li>Left hemisphere only </li></ul><ul><li>Responsible for fine coordination of speech </li></ul><ul><li>Broca’s aphasia </li></ul><ul><ul><li>Acquired language disorder characterized by short, aggrammatical sentences, difficulty with word retrieval, slow labored speech and writing, speech sound errors and difficulty with speech imitation. </li></ul></ul>
    23. 23. Parietal lobe <ul><li>Sits above the ears on the left and right sides behind the frontal lobe. </li></ul><ul><li>Functions: </li></ul><ul><ul><li>Perceive and integrate sensory and perceptual information </li></ul></ul><ul><ul><li>Comprehension oral and written language and calculation for math. </li></ul></ul>
    24. 24. Temporal lobe <ul><li>Sits behind (posterior to) the frontal lobe, but below (inferior to) the parietal lobe. </li></ul><ul><li>Contains auditory cortex ( Heschl’s gyrus ) and Wernicke’s area . Both very important to communication. </li></ul>
    25. 25. Auditory cortex/Heschl’s gyrus <ul><ul><li>Controls fined-tuned analysis of the physical properties (physics) of sound, auditory perception and sensation. </li></ul></ul><ul><ul><li>Located in both hemispheres; each hemisphere responsible for particular tasks </li></ul></ul><ul><ul><li>Left auditory cortex: temporal processing </li></ul></ul><ul><ul><li>Right auditory cortex: melody, prosody, pitch (musical) </li></ul></ul>
    26. 26. Temporal lobe <ul><li>“ Wernicke’s area” </li></ul><ul><ul><li>Highly specialized area for processing and comprehension of oral and written language </li></ul></ul><ul><ul><li>In left hemisphere; it is where meaning is attributed to the stimuli sent forth from Heschl’s gyrus. </li></ul></ul><ul><li>Wernicke’s aphasia </li></ul><ul><ul><li>Acquired language disorder characterized by very fast strings of sentences with little pause for acknowledgment or turn taking. </li></ul></ul><ul><ul><ul><li>Content may be incoherent/incomprehensible but fluent and well-articulated. </li></ul></ul></ul>
    27. 27. Occipital lobe <ul><li>Sits in front of and above the cerebellum and behind the cerebrum. </li></ul><ul><li>Receives and processes visual information </li></ul>