Unit 2: The Airways The Upper Airways RSPT 1207 Cardio Pulmonary Anatomy & Physiology
Feb 11, 2016
Unit 2: The AirwaysThe 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.hopkins-gi.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