00:00
In this lecture, you are going to learn
the histology of important structures in
the oral cavity that have a role in the
digestive system. At the end of this
lecture, it's important that you understand
the structure of oral mucosa and also
the structure of the tongue, particularly,
the papillae on the dorsal surface of
the tongue, and also these taste buds, and
the role of the taste bud in detecting
taste. And then we're going to look at the
differences in the salivary glands, the
three major salivary glands: the parotid, the
sublingual, and the submandibular gland.
00:43
And finally, we will have a look at
the structure of the tooth. All these
structures in the oral cavity are very
important because they break down the
food mechanically. The secretions from
the salivary glands moisten the food and
then form a bolus, which enables the food
to then pass easily down the esophagus
into the stomach. The tongue is a very
important organ, not just for speech and
taste, but it acts as a shovel in the oral
cavity and helps also break down the food by
pushing it up against the hard palate, the
masticatory mucosa. And the teeth, of
course, are important structures in the oral
cavity because they also mechanically
break down the food into smaller
components that again can be passed
easily down the esophagus in
the bolus of food. Here on this slide, there
is three images for you to get an
orientation of the oral cavity. On the
left-hand side, you can see a midsagittal
section taken through the head, and
it shows the region of the oral cavity.
You can see the lip labelled, the tooth
labelled, and the tongue.
02:05
So just orientate yourself now as to
what structures, what major structures
you are going to study in this lecture. You
can't see the salivary glands here nor
can you see some of the details of the
teeth or the oral mucosa, but I will show
you other images during this lecture
to explain the histology of those
structures. On the right-hand side at the top,
you see an anatomical drawing of the
tongue. The tongue moves about freely in
the oral cavity as the organ of speech, but
also as I mentioned earlier, as an organ
that moves the food around and pushes it up
against the hard palate to help break down
that food. The tongue is supplied by extrinsic
muscles, muscles that attach to bony prominences
outside the tongue. The tongue
also has intrinsic muscles that help change
the shape of the tongue. And on the
dorsal surface of the tongue, that surface
that when you stick out your tongue,
you can see that surface. You can see
illustrated on the diagram at the bottom
on the right-hand side, the papillae, the
tongue papillae. They have very important
functions, and I'm going to refer to those
later on in this lecture. So this is
really just to orientate you as
to what region of the body,
the oral cavity, we are going to study in
this lecture.