Unit 3: The Airways The Upper Airways

Unit 2: The Airways The Upper Airways RSPT 1207 Cardio Pulmonary Anatomy & Physiology

The Airways • Respiratory tract : combination of organs and tissues that have one function – the transfer of gas to be used by the body. • This process exposes the respiratory tract to many environmental extremes

The Upper Airways • Consists of: – The nose – Oral cavities – The pharynx – The larynx

The Upper Airways • Function: There are 4 Functions – – – –

Direct respiratory gases to and from the lung Defense mechanism Humidify inspired air Heat inspired air

• Also involved with: – Speech – Eating, drinking – Smell

The Nose • Midline, external and internal structure • Upper third is bone and covered by skin • Lower 2/3 is cartilage

Functions of the Nose • Filters particles prior to entering lower airways • Humidify and heat inspired air • Provides a location for sensory receptors used in the sense of smell • Provides resonance for speech

Major Structures of the Nose

Major Structures of the Nose

Major Structures of the Nose

Nasal Cavity • Separated by the septum making it into a symmetric bilateral structure • Anterior portion formed by the septal cartilage • Posterior septum formed ethmoid and vomer bones

Nasal Cavity • External nares – (nostrils) the openings of the nasal passageway • Internally protected from particles by Vibrissae (nose hairs) • Immediately behind vibrissae is an open chamber called the vestibule

Turbinates/Conchae • As incoming gas flow enter posterior to the vestibule it is separated by the turbinates or conchae • By having the turbinates, surface area is increased for heat/moisture exchange

Turbinates/Conchae • Lines the nasal cavity like three walls • Twisted to allow particles to be filtered and air to be heated and humidified • Mucous membranes line turbinates, Mucous glands line

Choandae • Lumen – the space (hole) in a vessel, tube, or intestine • In the nasal passage this is call the Choandae • Choanal atresia is a common birth defect found in infants

Paranasal Sinuses • Consists of the: frontal, maxillary, ethmoid and posterior sphenoid Sinuses • Openings are along the nasal passage • Paired sinuses contain mucous glands and membranes • Helps strengthen the skull

Oral Cavity • Simply known as the mouth • Functions: – Alternate passageway for breathing – Start of the alimentary canal – Contains major speech structures – Facial expressions

Oral Cavity • Anteriorly begins with lips and mouth • Follows with oral vestibule and teeth and gums • Oral cavity begins after the teeth

The Palate • The palate is the roof of the oral cavity • Consists of: • Hard palate – anterior 2/3 of the palate and is bony • Soft palate – posterior 1/3 and is made of soft tissue.

The Palate • Protects the nasal passage from food • Aids in swallowing • Hard palate and tongue are used in speech • Uvula helps protect the airway from occlusion

The Soft Palate • Made of soft tissue • This allows for food to be passed out of the oral cavity to the pharynx • Two structures form the soft palate: – Palatoglossal arch (anterior) – Palato-pharyngeal arch (posterior)

The Uvula • As the arches of the soft palate come together they form the uvula • Protects the lower airways by being extremely sensitive to tactile stimulation • Can cause violent gagging and possibly vomiting

Palatine Tonsils • Lies in palato-glossal arch • Lympathic tissue that is part of the immune system

The Pharynx • Generally known as the throat • Divided into three areas: – Nasopharynyx – Oropharynx – Laryngopharynx

Nasopharynx • Located behind the nasal cavities • Contains: – Adenoids or Pharyngeal tonsils – Eustachian tube: • Runs between the back of the throat and middle ear • Equilibrates pressure in the middle ear • Acts like a pop-ff valve to release excess gas behind eardrum

Oropharynx • Located below soft palate down to base of tongue • Only portion that can be seen without exam tools • Contains: – Lingual tonsils: at base of the tongue, tactile stimulation will cause gagging

Laryngopharynx • Also called the hypopharynx • Located from base of the tongue to entrance of the esophagus • Contains: Epiglottis – structure that protects the opening to the lower airways which is the glottis – Strong but flexible fibro-cartilage flap that comes out of the larynx into the laryngopharynx

Swallowing • The most critical moment is when the food enters the laryngopharynx. • Any mishap in coordination can lead to the food being aspirated into the lower airway • There are more than 20 muscles that are involved in the act of swallowing • The interaction of the tongue, palate and epiglottis in moving the food from the oral cavity to the oropharynx to the laryngopharynx and the esophagus

Swallowing • Food is broken down and lubricated in the oral cavity • As one swallows the muscles of the tongue and mouth move food up and back • Soft palate protects the nasopharynx • Gravity moves food into oropharynx

Swallowing • When the tongue moves up & forward the epiglottis moves down and backward • Results in the glottis is covered as the food moves into esophagus • Once food is in esophagus, the epiglottis moves back in place to allow gas to enter trachea • http://www.hopkinsgi.org/multimedia/database/intro_250_Swallow.swf

The Larynx • Located immediately below the pharynx • Formed by: – Three large external cartilages • Epiglottis • Thyroid cartilage • Cricoid cartilage

– Three pairs of internal cartilages • Arytenoid cartilage • Corniculate cartilage • Cuneiform cartilage

The Larynx

Epiglottis

External Cartilages • All protect the airway • Thyroid cartilage is open in the posterior but it is solid in the anterior to protect the vocal cords inside them • Cricoid cartilage is rigid ring and is the only structure that encircles the airway

Internal Cartilages • Form a three sided pyramid of ligaments and muscles to control the movement of the vocal cords • Pitch of the voice is controlled by tightening and loosening the cords • Volume or loudness is controlled by the amount of air forced through the cords

Interior of Larynx • Viewing the glottis from above a clinician will see the base of the tongue on top • Below the tongue will be the epiglottis & between these two will stretch the 3 ligaments of the vallecula • Egan’s page 173, figure 7-35

Interior of Larynx • The base of the glottal triangle is opposite from the base of the tongue • Surrounding the true vocal cords are tissue folds that are called the vestibular fold or the false cords • Vallecula – space betweent the tongue & epiglottis  Important landmark in intubation

Vocal Cords • The vocal cords come together and separate during quiet breathing so that the glottis is always slightly open. • A Valsalva maneuver or laryngospasm are the only time the glottis closed completely • To close the glottis completely, not only requires bringing the vocal cords together but the person tightens all laryngeal muscles at the same time

Valsalva Maneuver • Purpose: When the body requires positive pressure for expulsion • Examples: urination, defecation, birth, vomiting, coughing, sneezing • Person must exhale forcefully against a closed glottis, building pressure in the abdomen and thorax • Side effects: – Increase thoracic pressure decreases output of heart – Increased pressure in head

Coughing • Cough reflex is triggered when there is an irritant in the tracheal bronchial tree • Deep breath: 12-15 mL/kg IBW, • Inspiratory hold: 3 seconds for air to get behind irritant • Compression: Valsalva maneuver. True cords close for 0.2 seconds, resulting intrathoracic pressure is 1001-200 cm H2O pressure • Expulsion: Glottis opens and velocity can reach 300-500 LPM