00:00
cells normally in normal histological sections.
But they exist and they are important.
00:02
Well let us move on and look at the larynx. Here is a
section on the right-hand side again of that
mid-sagittal section taken through the nasal
cavity and the oral cavity. And you can see
the larynx positioned in this particular section
through the body. Remember it is just below
the epiglottis and earlier on I explained the
importance of the epiglottis in closing over
the entry into the airway at the larynx as
the larynx is lifted during swallowing.
00:38
And labelled on the image in the middle, the histological
section of the larynx are various components
of the larynx. This section is through again
the center of the larynx of a person looking
towards you. So you can see on the right and
left-hand side of the airway going down through
the vestibule are two ventricles and then
above this ventricle is a ventricular fold
and below is a vocal fold. These two folds
are called the vocal folds, but the ventricular
fold is a false vocal cord. The true vocal
cord is a vocal fold that is labelled and lies
in the most inferior part of that ventricle. The
ventricles in the vestibule are very important
components because they help to change the
sounds of their voices. And I will talk a bit
about that in a moment. Now the vocal fold
is our true vocal cord. As supposed it is
facing you these extend in an anteroposterior
orientation and they, in fact, form the boundary
of the larynx of the airway going down in
towards the lungs through the trachea and
that boundary is called the rima glottis. And
the glottis opens and closes during respiration.
02:11
This vocal fold has got attachments. It has
got attachments from the vocalis muscle through
vocalis ligament. But this vocal cord
also can be influenced by other components.
02:29
When air passes along between these vocal cords,
the vocal cords vibrate and this vibration
can be moderated. They can be changed. The
vocal cord can become more tense or more relaxed
and that changes the type of vibration and,
therefore, the pitch of the sound. And the
tension on that vocal cord is produced intrinsically
by the vocalis muscle contracting. It is also
changed by very small cartilages and intrinsic
muscles that move those cartilages and change
the proportions of the glottis. So changing
the proportions or the diameter of the glottis
or the opening into the airways and change
in the tension on the vocalis, the vocal cord
is responsible for the pitch of their voices.
And phonation is really then also carried out by
the effects of the sound going through the
vestibule and the ventral that you see here
and also in the upper parts of our respiratory
system that gives out individual sound of our
vowels and our consonants. There are extrinsic muscles
to the larynx. They have no role in sound production.
03:56
They are the muscles that we use to actually
lift the larynx that I described before as
part of the swallowing process. Well let us look
at the trachea. Trachea has got a number of
The lecture Larynx and Epiglottis by Geoffrey Meyer, PhD is from the course Respiratory Histology.
Where are the vocal folds located relative to the ventricular folds?
The passage of air results in which of the following movements in the vocal cords?
The cricoid and epiglottis are mainly composed of which of the following types of cartilage, respectively?
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Good lecture but too montonus,looks a person is reading out the textbook