Voice Disorders Lecture 5.pdf

SLP 286 – Voice Disorders Presentation 5 Dr. Ahmed Nagy Associate Professor , Department of Speech and Language Pathology UAEU Muscular Modes of Inspiration 1- Abdominal Respiration 1. During inspiration, the diaphragm contracts, pushing down the abdominal contents and the anterior abdominal wall...

SLP 286 – Voice Disorders Presentation 5 Dr. Ahmed Nagy Associate Professor , Department of Speech and Language Pathology UAEU Muscular Modes of Inspiration 1- Abdominal Respiration 1. During inspiration, the diaphragm contracts, pushing down the abdominal contents and the anterior abdominal wall goes forward increasing the vertical diameter of the thoracic cavity. 2. During expiration, there is a contraction of the anterior abdominal wall, elevating the abdominal contents and diaphragm. This decreases the vertical diameter of the thorax. 2- Thoracic Respiration There is a greater contribution from the muscles responsible for increasing the volume of the rib cage via outward movement of the ribs. The diaphragm is still moving, but as the rib cage is out of the way, less effort is required by the diaphragm for achieving the same vertical level of descent. Respiration in males is mainly Abdominal Respiration in females is mainly Thoracic • Every respiratory cycle consists of a phase of inward air flow {inspiration}, followed by a phase of outward airflow {expiration} • At normal resting breathing physiology, there is no pause between the two phases and the result is an equal volume change from baseline across both phases The volume of air in the lung is never zero in normal individuals, there has to be a residue left in the lung to facilitate lung re-expansion in the following expiratory phase even after forced expiration The volume of air in the lungs could be measured during the different phases of physiological functions by a technique called spirometry Inspiratory Reserve Volume (IRV) • About 3,100 mL • The additional air that can be forcibly inhaled after the inspiration of a normal tidal volume. Tidal Volume (TV) • About 500 mL • The amount of air inspired during normal, relaxed breathing. Expiratory Reserve Volume (ERV) • About 1,200 mL • The additional air that can be forcibly exhaled after the expiration of a normal tidal volume. Residual Volume (RV) • About 1,200 mL • The volume of air still remaining in the lungs after the expiratory reserve volume is exhaled. Total Lung Capacity (TLC) • About 6,000 mL • The maximum amount of air that can fill the lungs (TLC = TV + IRV + ERV + RV) Vital Capacity (VC) • About 4,800 mL • The total amount of air that can be expired after fully inhaling (VC = TV + IRV + ERV = approximately 80 percent of TLC) • The value varies according to age and body size Inspiratory Capacity (IC) • About 3,600 mL • The maximum amount of air that can be inspired (IC = TV + IRV) Functional Residual Capacity (FRC) • About 2,400 mL • The amount of air remaining in the lungs after a normal expiration (FRC = RV + ERV). • During quiet respiration we use 10 to 15% of our total lung volume and 0.5L {tidal volume} of air during each inhalation and exhalation • For speech we use about 20% of our total lung volume; 1.2 to 1.5L of air • In a healthy adult, the average is 16-18 respiratory cycles/minute; children have a higher average rate than adults. Exercise increases the rate/minute. • Respiration for speech is called phonic respiration. It has a lower cycle rate/minute; more importantly, the relative duration of inspiration and expiration changes, and also the volume of air exchanged is greater for phonic respiration • During quiet breathing, the respiratory cycle is 40% inspiration & 60% expiration. During speech, the respiratory cycle is 10% inspiration & 90% expiration {we produce voice from the larynx during the expiratory phase of the respiratory cycle}. The diagram demonstrates that the pattern of expiration will vary between resting breath, conversational speech, and loud speech. • The variability in the pattern of expiration has to be implemented by the muscles controlling the volume of the rib cage and chest cavity • During speech, the abdominal muscles, the diaphragm, and intercostals all contribute to the expiratory pulses imposed on the expiratory airflow initially induced by the recoil of the lungs & the expiratory muscles • Both the group of muscles responsible for quiet inspiration and active expiration are interacting during expiration for speech • The active contraction of the abdominal muscles pushes the viscera inwards, there is no room for the contracting diaphragm to move down so the contraction results in an increase in the tone of the muscle under each base of lung. The resulting pressure from the contracting expiratory muscles is higher. • This increase in pressure will be reflected on the intra-alveolar pressure of the lung and result in a higher airflow rate from the respiratory system to the atmosphere • Phonation is one of the physiological functions of the larynx, it is defined as the process of production of voice by the vocal folds • It is a mechanism in which aerodynamic energy from respiration is converted into sound waves by the vocal folds • Sound is defined as an audible disturbance of a medium produced by a source • In the case of human sound waves the medium is atmospheric air in which human sound waves propagate, meanwhile the source of this sound wave is the human vocal folds in the larynx Thank You