Chapter 24 Flashcards
Pharyngeal Arches
I- Mandibular Arch
II- Hyoid Arch
III, IV, VI- Other Arches
V- Disappears
What happens at about 4 1/2 weeks?
The Buccopharyngeal membrane ruptures , but the epithelium in that area still comes from two distinct germ layers.
What Happens after the buccopharyngeal membrane ruptures?
The tongue begins to develop as a swelling that arises out of the back of the pharyngeal arches.
What is the tongue?
A sac of epithelium filled with muscles.
What does the anterior 2/3 of the tongue develop from?
Two lateral lingual swellings and a midline tuberculum impar from the first arch.
What does the posterior 1/3 of the tongue develop from?
the copula and the third arch.
What does the root of the tongue and epiglottis develop from?
The epiglottal swelling of the fourth arch.
The tongue muscles are generally referred to as what?
Skeletal Muscles or voluntary striated muscles.
What are the two groupings of the tongue muscles?
Intrinsic and Extrinsic Muscles
Intrinsic Tongue Muscles
Start and develop wholly within the tongue.
What are the 4 groups of Intrinsic Muscles?
- Superior Longitudinal Group
- Inferior Longitudinal Group
- Transverse Group
- Vertical Group
What is the Superior Longitudinal Group?
Runs from the front to the back (anterior to posterior) and lies near the Dorsum of the tongue.
What is the Inferior Longitudinal Group?
Runs anterior to posterior but lies near the bottom or venture of the tongue.
What is the Transverse Group?
Runs from side to side.
What is the Vertical Group?
Runs from top to bottom (dorsal to ventral).
What group of fibers shorten the tongue when contracted?
Longitudinal group
What group of fibers make the tongue longer and thicker when contracted?
Transverse group
What group of fibers make the tongue wider and longer when contracted?
Vertical group
Extrinsic Tongue Muscles
4 pairs of muscles, left to right
What are the 4 pair of Extrinsic Muscles?
- Hyoglossus
- Styloglossus
- Palatoglossus
- Genioglossus
Hyoglossus
runs from the lateral sides of the hyoid bone up into the lateral borders of the tongue and pulls the lateral edges or borders of the tongue down onto the floor of the mouth.
Styloglossus
Runs from the Styloid process down and forward into the lateral borders of the tongue and blends with the hyoglossus. It pulls the tongue backward and slightly up.
Palatoglossus
Runs from the anterior soft palate down and slightly forward into the lateral borders of the tongue. It elevates the posterior part of the tongue and pulls it slightly backward.
Genioglossus
Originates from the superior genial tubercles on the midline of the mandible and inserts into the midline of the tongue from the tip to the base. It aids in protrusion or depression of the tongue.
What epithelium covers the tongue?
Stratified Squamous Epithelium
What are the 4 types of papillae?
- Circumvallate or Vallate Papillae
- Fungiform Papillae
- Filiform Papillae
- Foliate Papillae
What are the Circumvallate or Vallate Papillae?
A V-shaped row of circular raised papillae. There are about 13 elevations located about 2/3 of the way back on the tongue with the point of the V facing backward.
What are the Fungiform Papillae?
Anterior 2/3 of the tongue have tiny, round, raised spots.
What are the Filiform Papillae?
Remainder of the anterior 2/3 of the tongue is covered with tiny pointed projections of parakeratinized to keratinized epithelium known as filiform papillae.
What is it called when the epithelia on the Filiform papillae grow very long and trap between them food and pigments originating from oral bacteria and food?
Hairy Tongue
What is it called when the Epithelia of the Filiform Papillae are lost and the surface in that area become really smooth?
Glossitis
What are the Foliate Papillae?
Tongues lateral surface back- (Posterior lateral borders of the tongue). AN AREA WHERE ORAL CANCER CAN BEGIN.
Tastebuds
Salty, sweet, sour, bitter
