Flashcards in Structure of the Airway Deck (44):
What is the purpose of respiration?
+ Provide oxygen to the body through inhalation
+ Remove carbon dioxide through exhalation
How is inhalation/inspiration achieved?
By increasing the size of the thorax
How is increasing the size of the thorax achieved?
+ Contraction (and lowering) of the diaphragm and raising the ribs
+ Creating a negative intra-thoracic pressure that sucks air through the conductive passages and down into the lungs
What are the conductive passages of the respiratory system?
+ Nasal cavity
What must happen to the air that is inhaled/inspired?
It must be warmed, filtered and humidified (vascular mucosa, cilia, mucus)
How is exhalation achieved?
By decreasing the size of the thorax, a generally passive process
The nose is an external structure that anteriorly encloses which cavities?
- the start of the respiratory tract
- held open by bone and cartilage
Where are the nasal cavities located?
+ Above the oral cavity
+ Between the two orbits
+ Posterior to the nose
+ Anterior to the nasopharynx
What are the nasal cavities lined with?
A highly vascularised mucosal membrane lined with respiratory epithelium (pseudostratified, cilited, columnar, interspersed with goblet cells for mucous secretion)
What is the nasal septum?
A midline structure that separates the left and right nasal cavities
What is the composition of the nasal septum?
+ Anteriorly, made of septal cartilage
+ Posteriorly, made of bone
What happens if the septum deviates from the midline?
Sinus drainage may be compromised
What are the boundaries of the nasal cavities?
+ Bone (ethmoid, frontonasal, sphenoid; roof)
+ Nasal septum (medial)
+ Hard and soft palates (floor)
+ Nasal conchae (lateral)
What are the physical features that form the nasal cavity?
+ Frontal sinus
+ Maxillary sinus
+ Hard palate
+ Nasal septum
+ Middle concha
+ Middle meatus
+ Inferior concha
+ Inferior meatus
What is another name for conchae?
Where are conchae situated?
They project from the lateral wall and overhang the meati, into which the sinuses open
Where are the orbits in relation to the nasal cavity?
What is different about the opening of the maxillary sinus and why might that cause problems?
+ Opening is high in its medial wall
+ Clearance of mucus is dependent upon ciliary action which may be compromised due to infection
+ This can lead to possible sinusitis, as can a deviated septum
What is the role of sinuses?
To assist in warming incoming air
What is the role of the nasolacrimal duct?
Enters the nasal cavity to drain tears from the conjunctiva of the eye
What are the sinuses of the face?
What is another term for nosebleeds?
Between which branches do the vessels of the highly vascularised nasal mucosal membrane anastamose?
+ External carotids
+ Internal carotids
Where are the olfactory and the olfactory nerves located?
In the roof and upper parts of the lateral wall
What is the pharynx?
+ A tube of fibrous and muscular tissue that can be divided into 3 parts.
It lies behind:
+ The nasal cavity (nasopharynx)
+ The oral cavity (oropharynx)
+ The larynx (laryngopharynx)
What are functions/features of the nasopharynx?
+ Transports air
+ Divided from oropharynx by soft palate
What are functions/features of the oropharynx?
+ Transports air, fluid, and food (but these must be separated so air passes into the larynx while food and fluid continue into the laryngopharynx
+ Superior to the epiglottia
What are functions/ features of the laryngopharynx?
+ To transport food and fluid
What is the larynx?
+ A membranous tube suspended between cartilages, the positions of which are controlled by muscles
What does altering the laryngeal diameters allow?
+ The passage of air only
+ The control of airflow for speech and raising intra-abdominal pressure
What are the physical features of the larynx?
+ Epiglottic (elastic)
What is the clinical significance of the cricothyroid membrane?
It is the site of emergency access to the airway
Where is the ary-epiglottic fold?
Upper edge of the quadrangular membrane
Where is the vestibular fold?
Lower edge of the quadrangular membrane
Where is the vocal fold?
Upper edge of the cricovocal/cricothyroid membrane
What are the ary-epiglottic folds formed from?
Laringeal inlet, which is the protective sphincter
How does the laryngeal inlet close?
+ By elevation of the larynx which is lifted up and forwards during swallowing
+ Muscles within the ary-epiglottic folds aid both closure and widening of the laryngeal inlet
What are the folds and saccule/ventricles of the larynx?
+ Vestibular fold
+ Laryngeal ventricle
+ Vocal ligaments
What do the vocal folds control?
Laryngeal diameter for:
- raising intra-abdominal pressure
Vital in micronutrition, defecation and lifting heavy objects.
What are the main actions of laryngeal muscles?
1. Close/open the laryngeal inlet (ary-epiglottic folds)
2. Close/open rima glottidis (arytenoid gliding and rotation)
3. Shorten/lengthen the vocal folds ("rocking" at cricothyroid joints)
What is the only muscle that can open the rima glottidid?
What is the role of the superior laryngeal nerve?
It supplies only 1 muscle and sensation ABOVE vocal cords
What is the role of the recurrent laryngeal nerve?
It supplies all other muscles, and sensation of vocal cords and below