Nasal and Oral Cavity Flashcards
What is the piriform aperture formed by?
the right and left maxilla inferiorly and the two small nasal bones superiorly
What divides the nasal cavity into right and left sides?
a midline bony (perpendicular plate of the ethmoid and the vomer) and cartilaginous nasal septum
What structure of the nasal cavity contains a large amount of hairs to help filter inhaled air?
the nasal vestibule
Immediately posterior to the nasal vestibules is what?
the three nasal conchae, superior, middle, and inferior
The three nasal conchae divide the lateral spaces of the nasal cavity into what?
a series of groove-like passageways, the meatuses
The superior and middle concha are part of which bone?
the ethmoid bone. The inferior concha is a separate bone (the inferior turbinate)
Are the meatus’ below or above their associated concha?
below
Above the superior concha is a space called?
the sphenoethmoidal recess
What are some of the functions of the mucosa of the nasal cavity?
they help to filter inhaled air by trapping particles in the mucus, and the epithelial cells bear cilia that sweep the secretions toward points where the mucus can be eliminated (either by blowing your nose or sniffing hard enough that the secretions end up in the pharynx and are swallowed). They also help warm the air via increased surface area created by the concha
Hairs in the vestibule and mucus that is produced by goblet cells or secreted by glands trap particles larger than?
> 10 um
Some of the large particles are also trapped by what?
cells of the palatine and pharyngeal tonsils. By the time air reaches the trachea, most of the larger particles have been filtered out. The trachea then removes most particles from the 2-10 um size range
Particles trapped in the trachea are removed via what processes?
coughing and mucokinesis
Particles less than 2 um are removed where? By what mechanism?
in the lungs via phagocytosis by alveolar macrophages (dust cells)
NOTE: since alveolar membranes are very thing, they could dry out with not for the humidification that takes place in the airway spaces down through the bronchi
T or F. There is no mucus in health alveoli and there are ciliated cells
F. There are neither
The floor of the nasal cavity is made up of what bones? aka the hard palate
the palatine process of the maxilla (anterior 3/4) and the horizontal process of the palatine bone (posterior 1/4)
Where does the soft palate attach to the floor of the nasal cavity?
in the posterior region and hangs down posterior to the choanae. The soft palate also forms the roof of the oral cavity
What is the roof of the nasal cavity formed by?
the cribriform plate of the ethmoid bone
Where does the olfactory epithelium containing CN I neurons lie?
just inferior to the cribriform plate on the septum and the superior lateral walls of the nasal cavity
What is the anterior wall of the nasal cavity bound by?
nasal bones and cartilage
What is the posterior wall of the nasal cavity bound by?
sphenoid bone
What does the nasal septum consist of?
septal cartilage (tip of the nose), perpendicular plate of the ethmoid, and the vomer
When you breath quietly, where does air go?
it is guided across the inferior concha and through the MIDDLE meatus. Some air does cross the olfactory epithelium near the roof of the nasal cavity, but only a small amount unless you sniff (as to smell) strongly and create the turbulence required to force more air across the olfactory receptors
Where does the sphenoid sinus drain to?
The posterior ethmoid air cells?
The anterior ethmoidal air cells, frontal, and maxillary ?
The middle ethmoid air cells?
1) the sphenoethmoidal recess, above the superior meatus.
2) superior meatus
3) the hiatus semilunaris
4) bulla ethmoidalis
Where is the sphenopalatine foramen located?
just posterior to the middle concha where the vertical portion of the palatine bone meets the sphenoid
Where are the greater and lesser palatine foramen located?
near the posterior end of the hard palate in the lateral aspect of the palatine bone where the vertical and horizontal plates meet
What bone is directly posterior to the palatine bone?
the pterygoid process of the sphenoid bone (and the body of the sphenoid bone)
What are the four paransala sinuses?
maxillary, frontal, ethmoid air cells, and sphenoid
Describe the route of the maxillary nerve?
courses through the pterygopalatine fossa, giving off several branches, some which pass through some small named foramina in the lateral wall, or through the greater and lesser palatine foramina DOWN into the oral cavity.
All of the maxillary nerve branches just described carry what?
GSA from the mucosa of the nasal cavity. Their cell bodies are in the trigeminal ganglion in the middle cranial fossa
What fibers run with the branches of V2 to the nasal cavity and roof of the oral cavity and palate to innervate mucus glands there?
postganglionic GVE fibers from the pterygopalatine ganglion (CN VII)
The branches of V2 that enter the sphenopalatine fossa do what?
they can either course along the lateral wall of the fossa or can navigate the roof of the fossa medially and descend down along the septum in the midline
Where is the pterygopalatine fossa located?
in between the maxillary and lateral pterygoid plate (lateral to the sphenopalatine fossa)
What branches does the maxillary n. give off in the pterygopalatine fossa?
the maxillary n. itself goes into the fossa and anteriorly into the orbit, but it gives off lateral nasal branches that pass through the SP fossa to distribute over the conchae. It also gives off greater and lesser palatine nerves that distribute into the roof of the oral cavity. The greater palatine n. runs anterior once passing through the greater palatine fossa and the lesser palatine n. runs posteriorly once exiting its fossa. Both these course lateral to the palatine bone (i.e. they DO NOT pass through the SP at the top)
What do the lateral nasal nn. from the maxillary n. innervate?
the conchae
What do ethmoidal nerves branch from?
the nasociliary n. (branch of V1)
What do the ethmoidal nerves innervate?
ethmoidal air cells, sphenoid sinus, lateral nasal wall (goes inside the SP fossa), and septum
What does the nasopalatine n. branch from?
posterior superior nasal nerve (from maxillary)
Where does the nasopalatine nerve run?
it arches along the middle of the septum (so it passes into the SP) on either side and descends obliquely toward the incisive canal