Tongue:
- What are the layers of tongue?
- Mucosa
- Partially keratinized stratified squamous epithelium
- Lamina propria
- Thick muscular layer
- Why is epithelium rough on dorsal surface?
- The epithelium is rough on dorsal surface due to the projections called papillae
- Name 4 types of papillae/ what are the 4 types of papillae?
- Filiform
- Fungiform
- Circumvallate
- Foliate
- Which papillae is not seen in humans / which papillae is absent in humans?
- Foliate
- Which papillae are more numerous?
- Filiform is more numerous covering entire anterior 2/3rd of dorsal surface of tongue
- Which papillae is keratinized and which are non-keratinized?
- Filiform is keratinized
- Fungiform and circumvallate are non keratinized
- What is the distribution of fungiform papillae?
- It is distributed at the tip and sides of tongue
- What is the distribution of circumvallate papillae?
- Around 12 to 15 circumvallate papillae are present at the junction of anterior 2/3rd and posterior 1/3rd of the tongue
- Describe filiform papillae
- Filiform papillae are bent sharp conical projections of epithelium directed posteriorly. It is partially covered by keratin at the tip
- Describe fungiform papillae
- They are mushroom shaped larger, taller and broader papillae
- It has core of lamina propria surrounded by non-keratinized stratified squamous epithelium
- Few taste buds may be present towards surface of epithelium
- Describe circumvallate papillae
- It is surrounded by deep trench or furrow. It is lined by non-keratinized stratified squamous epithelium with a core of lamina propria
- Lamina propria has numerous secondary papillae projecting into epithelium. It has connective tissue, blood vessels, nerves, lymphatics and von Ebner’s glands which open into trench
- Taste buds are present on lateral walls
- Where are the taste buds present?
- They extend along the whole thickness of epithelium in lateral wall of circumvallate papillae and on surface epithelium of fungiform papillae
- Describe taste buds
- Sustentacular cells or supporting cells- elongated with dark cytoplasm and slender dark nucleus
- Gustatory cells or taste cells or sensory cells or neuroepithelial cells- lighter cytoplasm and oval light nucleus
- Basal cells near basement membrane of taste bud
- It has a small opening in the center which opens towards the epithelial surface
- What are intragemmal and intergemmal fibers?
- Intragemmal fibers- sensory fibers ending within the taste buds
- Intergemmal fibers- fibers ending freely in epithelium in between taste cells
- Name the components of lamina propria
- Loose connective tissue
- Blood vessels
- Nerves
- Lymphatics
- What is the arrangement of muscular layer
- Muscular layer is very thick and fibers are arranged in various directions
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