hi let's talk about the nose nasal cavities mouth and oral cavity in this video we'll discuss
the external features of the nose the internal features and the functions of the nose and
nasal cavities as well as the nasal conchae and their functions as well as the structures that
comprise the nasal septum and finally we'll discuss the oral cavity and its organization
so the external nose consists of nares or nostrils that are separated by the nasal columella this
is just a skin covered fleshy part that is an extension of the nasal septum that would divide
the left from the right nasal cavity you can palpate your own and feel that there is nothing
within it that is of the septum surrounding the nares are the ayla or the wings of the nose
and we can see that the nose here is a part of the respiratory pathway it is exclusively
a respiratory organ it is not involved in the aerodigestive pathway which would be the mouth
and pharynx although the nose and nasal cavities do communicate with the nasopharynx as we'll see
so there are two nasal cavities a left and a right and they are separated by the nasal
septum and we'll get to that in just a moment so here is the nose as we saw here is the nearest we
cannot see the color mellow because it has been cut away as has the nasal septum on the side
and we're looking at the lateral wall of the nasal cavity here so this is nasal cavity
here is the nasal vestibule that would be the space that's surrounded by the external nose
the nasal vestibule is the anterior portion of the nasal cavity
as we move from the nasal vestibule inside the cranium we're still within the nasal cavity
the nasal cavity has medial and lateral walls the medial wall is quite smooth it's just the
nasal septum invested with mucosa the lateral wall is very complex and it consists of three conchi
these conchi or turbinates are of various bones so for instance the superior and middle conchae
are of the ethmoid so they're oftentimes referred to as ethmoturbinates the inferior concha are of
the are of their own bone so they are their own separate centers of ossification the nasal septum
consists of three elements which we can see here so there's the septum
anteriorly we have the septal cartilage posterior inferiorly we have the vomer
foamer is meaning plow share because it's shaped like a plow and then the perpendicular plate
of the ethmoid bone
as we move to the posterior portion of the nasal cavity there is a space called the kiwana
pleural kawani because there are two of them one for each nasal cavity that is a communication
between the nasal cavity and a part of the pharynx called the nasal that's well named pharynx
so that's the superior most portion of the pharynx that goes from the choanae down to a plane
extending through the soft palate so all of this space here is the nasopharynx
so the nasal cavity is invested by nasal mucosa
and as an individual breathes in the air that they breathe in through their nose
is both warmed and humidified so as to not be a shock to the lungs and any impurities in the air
can get captured by that nasal mucosa to prevent them from going down into the lungs so if you've
ever spent a a day in a dusty environment or in a very you know developed city you might
at the end of that time blow your nose and that nasal mucus may be very dirty from all of those
air impurities now if we look at that lateral wall in greater detail we'll see that associated with
every concha is a meatus so there's the superior there is the middle conka and then there's the
inferior concha and underneath these spaces are the meatuses so there's the superior
nasal meatus there's the middle nasal meatus and there's the inferior nasal meatus
and then above the superior concha is a region called the sphenoethmoidal recess
now within these meatuses are communications with paranasal sinuses so
for instance the sphenoethmoidal recess contains the ostium or the opening to the sphenoid sinus
this superior meatus here can communicate with some of the ethmoid cells of the ethmoid sinus
the middle nasal meatus can communicate with the frontal sinus through the ethmoidal
infundibulum as well as the maxillary sinus as well as some of the ethmoidal sinuses so
there's a lot going on in that middle nasal meatus and then the inferior nasal meatus
receives the nasolacrimal duct from the medial canthus of the eye so we have a
lot of communications moving mucus and lacrimal fluid between other regions and the nasal cavities
the mouth or the oral fissure sits between two labia and superior and and inferior and this
one is wide open so it's maximally patent so as to reveal the oral cavity the oral cavity can be
further subdivided into the oral vestibule in the oral cavity proper so if we look at
the dental arcades so there are the teeth those are the maxillary teeth and the mandibular teeth
the space external to the dental arcade but internal to the lips and cheeks that is the oral
vestibule so the teeth and the supporting gingiva or gums helps to divide that oral vestibule from
the oral cavity proper within the oral cavity proper there is the tongue and we can see here
is the mucosa of the floor of the mouth which is continuous with the tongue and below that mucosa
is the sublingual space which is still of the oral cavity proper that sublingual space goes down to
a set of muscles called the mylohyoid muscles so that would be the floor of the oral cavity
proper and the floor of the sublingual space now posteriorly we can divide the oral cavity
from the oropharynx by a set of folds called the palatoglossal folds and we'll discuss this in
greater detail when we discuss the pharynx this is the beginning of a region called the phos which is
the anterior most part of the oropharynx suffice it to say the barrier between the oral cavity and
the oropharynx are these palatoglossal folds which are oral surrounding the palatoglossal muscles
and that leads us to the assessment question for this video and that is which bone has features
including two sets of conkey in a large portion of the nasal septum is it the ethmoid the maxilla the
palatine the sphenoid or the vomer well the three parts of the nasal septum are the septal cartilage
the vomer and the ethmoid so we can eliminate the other three of these and then when we
think of the two sets of conchi the superior and middle conchae are known as the ethmoturbinates
so the correct answer to this question is a ethmoid thank you very much for your time