Voice Disorders Lecture 4.pdf

SLP 286 – Voice Disorders Presentation 4 Dr. Ahmed Nagy Associate Professor , Department of Speech and Language Pathology UAEU Anatomy and Physiology of respiration There are two main subdivisions of the respiratory system 1. The upper respiratory tract 2. The lower respiratory tract Upper res...

SLP 286 – Voice Disorders Presentation 4 Dr. Ahmed Nagy Associate Professor , Department of Speech and Language Pathology UAEU Anatomy and Physiology of respiration There are two main subdivisions of the respiratory system 1. The upper respiratory tract 2. The lower respiratory tract Upper respiratory tract • Mouth • Nose – The nostril is the preferred route as it warms , cleans , and humidifies the air • Sinuses: Air cavities within the facial bone of the skull, continuous with the nasal cavity • Pharynx • Larynx Lower Respiratory tract 1. The portion of the Larynx below the vocal folds 2. The trachea 3. Bronchi 4. Bronchioles 5. Alveoli {site of gas exchange with blood} 4 + 5 = Specialized connective tissue of the lung • Right lung 3 lobes • Left lung two lobes ( space for heart) The lungs are “ housed “ within the thoracic cavity. For voice production , the air forced out of the lungs during expiration is the fuel for phonation The volume of this air is affected by the amount entering during inhalation . The rib cage functions : 1- To protect the lung’s delicate tissue from external trauma 2- To allow the muscles of inspiration and expiration to change lung volume and move air in and out of the respiratory system The Skeletal { Bony } Thorax Also called the rib cage, its components are 1- Manubrium, Sternum, Xiphoid process {central front} 2- Vertebrae { central back} 3-Clavicle and Scapulae 4- Ribs { sides , front to back} The manubrium forms the upper part of the front of the rib cage . { also called Manubrium sterni } Articulates with the Body of the sternum (corpus) , at the manubriosternal joint { creating an elevated ridge on the anterior surface. Most inferior part of the bone is the Xiphoid process . It extends the length for further muscular attachments The length of the front of the rib cage articulates with the Clavicle bone { collar bone } , and the first 7 thoracic ribs . T1 to T7 Rib pairs 1 to 7 are true ribs , attached directly to the sternum by costal cartilages Rib pairs 8 to 10 are false, they do not contact the sternum directly, but through the costal cartilage of the 7th rib pair. 11 & 12 pair are floating ribs with no direct or indirect connection to the sternum Physics Bulletin Pressure is force / unit area The mass of air particles exert a force on the container around them or on all surfaces in contact with them, this force is described as the air pressure and it is equal in all directions In respiratory science, pressures are designated values relative to the pressure of atmospheric air on surfaces Positive pressures are higher than atmospheric pressure Negative pressures are lower than atmospheric pressures Air always flows from higher pressure to lower pressure Boyle’s law states that for a given mass of gas at constant temperature, the volume of the gas varies inversely with pressure. http://www.chemistrytutorials.org/conte nt/gases/ideal-gas-law-withexamples/22-density-and-mixtures-ofgases-with-examples The lung tissue is surrounded by a sac of epithelium tissue This is the pleural sac The layer touching the lung tissue is named the visceral pleura The layer lining up the inner surface of the muscles and ribs forming the rib cage is called the Parietal layer The epithelium of the sac is simple squamous also called Mesothelium { hence the name mesothelioma} The space between the two layers is called the pleural cavity In healthy individuals it has no air , it is minimal in volume, continuous with no adhesions with a thin layer of mucous lubricating the interface between the Visceral and parietal pleura At rest : ( a moment of voluntary breath cessation after normal expiration ) With no airflow the pressure of air in the bronchial tree { intra-alveolar pressure} is 0 , as it is now continuous with the atmosphere {atmospheric pressure } The rib cage is structurally rigid (muscles and bone), it attains a fixed position The lung tissue is rich in collagenous and elastic fibers to allow expansion and compression with respiratory movement, { compliance}. At this instant the lung has a natural passive tendency to collapse on itself, however in healthy individuals this is only a very small inward pull on the visceral pleura relative to the parietal layer The overall result is a weak negative Intrapleural pressure { intrathoracic pressure} , measuring – 1 mmHg relative to the atmosphere. Aronson, clinical voice disorders, 2009) The physiological process of Air flow into and out of the respiratory system is called the respiratory cycle. The air moves in and out as a result of an interplay between : • Intra-alveolar pressure • Atmospheric pressure • Intrathoracic Air flow occurs from the atmosphere into the lungs when atmospheric pressure is higher than Intra-alveolar pressure , this is called inspiration. Air flow occurs from the lungs into the atmosphere when Intra-alveolar pressure is higher than atmospheric, this is called expiration. Aronson, clinical voice disorders, 2009) Inspiration at rest • The muscles of inspiration increase the volume of the rib cage • The increased pull on the parietal pleural outwards results in greater negative { increased in negativity} of intra thoracic pressure • The negative pull of the intrathoracic pressure pulls the soft compliant lung tissue outward • The volume of intra-alveolar space increases on a fixed volume of air • There is an increase in the negativity of the intra-alveolar pressure relative to atmospheric pressure • Air flows from the atmosphere into the lungs Expiration at rest The muscles of inhalation relax The rib cage returns to resting position The intra thoracic negativity decreases { becomes closer to zero This allows the lungs to recoil towards resting size The volume of intra-alveolar space decrease on a fixed volume of air The air pressure will increase above that of the atmosphere and air will flow out of the lungs The process is passive with no active muscular contraction Aronson, clinical voice disorders, 2009) Muscles of Quiet Inhalation 1-The Diaphragm Origin: • Sternum and Xiphoid process • Lower 4-5 ribs • Parts of lumbar vertebrae Insertion: The central tendon of the diaphragm Nerve supply: The Phrenic nerve {C3, 4,& 5} Function: • Muscle fibers contract drawing their periphery closer to the central tendon • The diaphragm descends and flattens increasing vertical chest diameter 2-External intercostal muscles • Origin: Lower edge of an upper rib • Insertion: Upper edge of rib immediately below • Nerve supply: Intercostal nerves {T1 to T11} • The first rib is stationary • The barrel shaped expansion of the chest allows greater diaphragmatic descent and expands ribcage Quiet Exhalation: It is brought about by passive forces that make the rib cage and muscles of inhalation return to their resting positions • Gravity • Elastic recoil of lungs and ribs • Elastic recoil of abdominal viscera • There are a few instances that make humans require more oxygen than they do at baseline activity levels • Increasing the volumes of air breathed in and out of the respiratory system/unit time is a physiological response to higher oxygen demand e.g. exercise. • The muscles of accessory inspiration and expiration are activated along with the forces active during the baseline respiratory cycle • They are called the muscles of accessory respiration, and they induce greater and faster volume changes in the rib cage. Accessory Muscles of Inhalation • Sternocleidomastoid • Scaleni • Subclaveus • Pectoralis Major • Pectoralis Minor • Serratus • Latissimus Dorsi Sternocleidomastoid Origin : • MEDIAL third of clavicle • Manubrium of sternum Insertion: Mastoid Process Nerve supply: Cranial XI Action: Flexes the neck • If the head is fixed, contraction will elevate sternum and clavicle; this will increase the vertical diameter of the chest cage Scaleni Origin: C2 to C6 Insertion: Ribs 1 and 2 Nerve supply: C3 to C8 Action: Bends the neck Ventral and lateral • Most important contributor to forced inspiration • When the neck is fixed, ribcage is elevated Pectoralis Major Origin: Manubrium, portions of clavicle, ribs, and sternum Insertion: Humerus {upper bone of arm} Nerve supply: C5 to C8 and T1 Action: Bring the arm closer to the body • If arm is fixed, elevates ribs and sternum • In contrast to passive, quiet expiration, the need for a greater respiratory pace {more cycles/second} requires the active recruitment of the muscles of accessory expiration • Rectus Abdominus • Transversus Abdominus • Internal Oblique Abdominus • External Oblique Abdominus Rectus Abdominus Origin: Costal cartilage of ribs 5-7, xiphoid process, and sternum Insertion: Front of hip bone Nerve supply: T7 to T11 Action • Compress rib cage • Compress abdomen pushing diaphragm up • Decrease vertical dimension of chest Transversus Abdominus Origin: Bottom 3 ribs, parts of the xiphoid process, parts of the pelvic girdle Insertion: broad, flat tendon surrounding the abdomen Nerve supply: T6 to T12 and L1 Action: • Compress abdomen pushing diaphragm up • Decrease vertical dimension of chest Thank You