📚 Exploring the Histology of Lips and Tongue with Dr. Muhammad Ali Rabbani 📚 Join Dr. Muhammad Ali Rabbani, Assistant Professor of Anatomy, on an enlightening journey through the histology of lips and tongue. This lecture is designed for students seeking a comprehensive understanding of the intricate structures and functions of these oral components. 📚 Learning Objectives 📚 By the end of this lecture, students will be able to: - Describe the histological features of the lip, emphasizing the transition from cutaneous to vermillion to mucosal zones. - Explain the histological features of the dorsal and ventral surfaces of the tongue, focusing on tongue papillae, their shape, location, keratinization, number, and the presence or absence of taste buds. 🎓 About the Speaker 🎓 Dr. Muhammad Ali Rabbani holds an impressive array of qualifications, including MBBS, FCPS in Anatomy, CHPE, DHPE, MBA, and MPH. As an Assistant Professor, his passion for anatomical education shines through in this lecture. 🔬 Oral Histology Expedition 🔬 Dr. Rabbani will guide you through the following key aspects: 1. Oral Cavity Overview - Divisions: Vestibule, Oral Cavity Proper - Structures: Tongue, Teeth, Periodontium 2. Mucosa Types - Masticatory, Lining, Specialized - Epithelium: Stratified squamous, keratinized, partially keratinized, non-keratinized 3. Masticatory Mucosa - Location: Gingiva, Hard Palate - Keratinization: Keratinized, Para-keratinized - Lamina Propria: Papillary layer, connection with periosteum 4. Lining Mucosa - Location: Lips, Cheeks, Alveolar Mucosal Surface, Floor of Mouth, Inferior Surfaces of the Tongue, Soft Palate - Epithelium: Mostly nonkeratinized, occasional parakeratinized - Lamina Propria: Shallow papillae, distinct submucosa 5. Specialized Mucosa - Location: Dorsal surface of the tongue - Associated with taste sensation, papillae, and taste buds 6. Lips Exploration - Internal Mucosal Surface, Vermillion Zone, Outer Surface 7. Tongue Unveiling - Muscle Structure: Striated, extrinsic, intrinsic - Surfaces: Dorsal and ventral surfaces - Sulcus Terminalis, Lingual Tonsils 8. Lingual Papillae - Types: Filiform, Fungiform, Foliate, Vallate (Circumvallate) - Structure and distribution 9. Taste Buds Revelation - Location: Vallate, Fungiform, Foliate papillae - Structure: Gustatory cells, Supportive cells, Basal Stem cells, Taste pore 10. Categories of Tastants - Detection of salty, sour, sweet, bitter, umami tastes - Mechanisms: Ion channels, G-protein–coupled receptors 11. Taste Sensitivity Map - Distribution of taste receptors on the tongue 12. Q&A Session - Dr. Rabbani invites your questions, suggestions, and feedback at info@medicoseacademics.com or call at +92310-7990649. 🔗 Connect with Us 🔗 https://www.youtube.com/@MedicoseAcademics https://www.facebook.com/medicoseacademics https://www.instagram.com/medicoseacademics/

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Histology of Lip & Tongue
Dr. Muhammad Ali Rabbani
Asst. Professor Anatomy
MBBS (NMC, Multan)
FCPS (Anatomy)
CHPE (Certificate in Health Professional Education)
DHPE (Diploma in Health Professional Education)
MBA (Masters of Business Administration)
MPH (Masters of Public Health)

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Learning Objectives
By the end of this lecture students should
• Describe the histological features of lip, with emphasis on transition
in structure from cutaneous to vermillion to mucosal zone.
• Explain the histological features of dorsal and ventral surfaces of
tongue, with particular focus on tongue papillae, their shape,
location, keratinization, number and presence or absence of taste
buds.
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Oral Cavity
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• The oral cavity consists of the mouth and its structures, which include
the tongue, teeth and their supporting structures (periodontium)
• Oral cavity is divided into
• Vestibule
• The space between the lips, cheeks, and teeth
• Oral Cavity Proper
• It lies behind the teeth
• the hard and soft palates superiorly
• the tongue and the floor of the mouth inferiorly
• the entrance to the oropharynx posteriorly
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Mucosa
The oral cavity is lined by the oral mucosa that consists of
• Masticatory mucosa
• Lining mucosa
• Specialized mucosa
Epithelium is stratified squamous which may be keratinized, partially
keratinized or non-keratinized depending on location
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Masticatory Mucosa
• Found on the gingiva (gums) and the hard palate
• Epithelium may be
• Keratinized
• Resembles skin, lacks stratum lucidum
• Para-keratinized
• similar to keratinized epithelium except that the superficial cells do not lose their nuclei
• Lamina Propria
• Consists of thick papillary layer of loose connective tissue
• In midline of hard palate and gingiva lamina propria blends with periosteum
(no submucosa)
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Lining Mucosa
• Found on the lips, cheeks, alveolar mucosal surface, floor of the
mouth, inferior surfaces of the tongue, and soft palate
• Epithelium of the lining mucosa is mostly nonkeratinized
• although in some places, it may be parakeratinized
• Vermillion border of lip is keratinized
• Lamina propria throws shallow papillae into epithelium
• A distinct submucosa underlies the lining mucosa
• except on the inferior surface of the tongue
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Specialized Mucosa
• Restricted to the dorsal surface of the tongue
• Specialized mucosa is associated with the sensation of taste
• It contains papillae and taste buds responsible for generating the
chemical sensation of taste
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Lips
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Lips
• There is well-developed core of striated muscle
• makes these structures highly mobile
• Both lips have three different covered surfaces
• Internal Mucosal Surface
• Vermillion Zone
• Outer Surface
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• Internal Mucosal Surface
• lining mucosa with a thick, nonkeratinized
epithelium
• many minor labial salivary glands.
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• Vermillion Zone
• is transitional between the oral mucosa and skin
• very thin keratinized stratified squamous epithelium
• lacks salivary or sweat glands
• very rich in both sensory innervation and capillaries
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• Outer Surface
• thin skin, consisting of epidermal and
dermal layers, sweat glands, and many hair
follicles with sebaceous glands
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Tongue
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Tongue
• The tongue is a mass of striated muscle covered by mucosa
• Manipulates ingested material during mastication and swallowing
• Muscle fibers are oriented in all directions (found only in this tissue),
allowing a high level of mobility
• Muscles are both extrinsic and intrinsic
• Connective tissue between the small fascicles of muscle is penetrated
by the lamina propria, which makes the mucous membrane strongly
adherent to the muscular core
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• The lower surface of the tongue is smooth, with
typical lining mucosa
• The dorsal surface is irregular
• A V-shaped groove called the sulcus terminalis
divides this surface into
• Anterior two-thirds – having hundreds of small
protruding papillae of various types
• Posterior one-third – having massed lingual tonsils
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Lingual Papillae
• The lingual papillae are elevations
of the mucous membrane that
assume various forms and
functions
• There are four types
• Filiform papillae
• Fungiform papillae
• Foliate papillae
• Vallate (or Circumvallate) papillae
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Filiform Papillae
• Most numerous
• Smallest among all
• Elongated conical shape
• Heavily keratinized, which gives their
surface a gray or whitish appearance
• Provides rough surface that facilitates
movement of food during chewing
• Does not contain taste buds
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Fungiform Papillae
• Less numerous than filiform
• Interspersed among the filiform papillae
• More numerous near the tip
• Mushroom-shaped
• Lightly keratinized
• Well-vascularized and innervated cores
of lamina propria
• Taste buds present on the dorsal surface
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Foliate Papillae
• Consist of several parallel ridges on each side
of the tongue, anterior to the sulcus terminalis
• Rudimentary in humans,
especially older individuals
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Vallate Papillae
• Largest papillae, with diameters of 1-3 mm
• Eight to twelve vallate papillae are normally
aligned just in front of the terminal sulcus
• Ducts of several small, serous salivary (von Ebner)
glands empty into the groove surrounding each
vallate papilla
• Secretions from these contain a lipase
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Taste Buds
• Ovoid structures within the stratified epithelium on the tongue’s surface
• Sample the general chemical composition of ingested
• These are present on
• Vallate papillae (250 per papilla on lateral surface)
• Fungiform papilla
• Foliate papillae
• NOT on the keratinized filiform papillae
• Also widely scattered elsewhere on the
• dorsal and lateral surfaces of the tongue
• glossopalatine arch
• the soft palate
• the posterior surface of the epiglottis
• the posterior wall of the pharynx down to the level of the cricoid cartilage
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Taste Buds – Structure
• A taste bud has 50-100 cells. These include
• Gustatory (taste) cells
• More than half
• Synapse with sensory axons (of CN VII, IX & X)
• 7-10 day life span
• Supportive cells
• Basal Stem cells
• Give rise to other cell types
• 10 day life span
• The base rests on the basal lamina that is entered by sensory axons
• At apex there is 2-μm-wide taste pore, through which microvilli project
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Taste Buds – Categories of Tastants
• Taste buds detect at least five broad categories of tastants
• salty - sodium ions
• sour - hydrogen ions from acids
• sweet - sugars and related compounds
• bitter - alkaloids and certain toxins
• umami - amino acids such as glutamate and aspartate
• Salt and sour tastes are produced by ion channels and the other three
taste categories are mediated by G-protein–coupled receptors
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• Some areas of the tongue are more
responsive to certain tastes than other
• However, studies with thermal stimulation
of the tongue have shown that the classic
taste maps as described above represent
an oversimplified view of the distribution
of taste receptors
• Sensitivity to all tastes is distributed across
the entire tongue, but some areas are
indeed more responsive to certain tastes
than others
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