Structure of the Airway Flashcards
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 \+ Nasopharynx \+ Larynx \+ Trachea \+ Bronchi
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?
Nasal 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?
Turbinates
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?
Immediately lateral
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?
+ Frontal
+ Ethmoid
+ Sphenoidal
+ Maxillary
What is another term for nosebleeds?
Epistaxis
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
