Oral Mucosa Anatomy and Composition

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Questions and Answers

What is the primary cause of albinism?

Lack of vitamin D

Low production or lack of tyrosinase enzyme (correct)

Deficiency in melanin production

Excessive UV exposure

Which type of immune cell are Langerhans cells categorized as?

Natural killer cells

Dendritic cells (correct)

Phagocytes

B lymphocytes

Which of the following characteristics is NOT associated with Langerhans cells?

Bone marrow precursors

Presence of desmosomes (correct)

Act as antigen presenting cells

Contain Birbeck granules

What is one of the roles of Langerhans cells in the immune system?

Propagate HIV infection Signup and view all the answers

Where are Merkel cells primarily located?

In the stratum basale close to nerve fibers Signup and view all the answers

What type of epithelium is primarily responsible for the specialized mucosa?

Non-keratinising epithelium Signup and view all the answers

Which of the following cell types is NOT considered a non-keratinocyte in oral epithelium?

Fibroblasts Signup and view all the answers

What does the submucosa primarily consist of in the lining and specialized mucosa?

Loose connective tissue and fat Signup and view all the answers

What structure directly separates the epithelium from the lamina propria in oral mucosa?

Basement membrane Signup and view all the answers

What is the primary function of masticatory mucosa?

Protection against mechanical stress Signup and view all the answers

Which type of mucosa primarily features keratinized epithelium?

Masticatory mucosa Signup and view all the answers

Which cell type is primarily involved in immune response in the oral epithelium?

Inflammatory cells Signup and view all the answers

What component is unique to masticatory mucosa compared to lining and specialized mucosa?

Periosteum and bone Signup and view all the answers

What is the primary role of melanocytes in the oral mucosa?

To produce melanin Signup and view all the answers

Which of the following statements about hyperkeratosis is correct?

It is associated with an abnormal increase in keratin production Signup and view all the answers

What happens to the keratinization level when inflammation occurs in oral epithelium?

It may appear parakeratinised or non-keratinised Signup and view all the answers

Which type of cells constitute approximately 10% of the cells in the epithelial layer?

Non-keratinocytes Signup and view all the answers

What is the origin of melanocytes during development?

Neural crest Signup and view all the answers

What is the role of melanosomes in melanocytes?

To synthesize melanin Signup and view all the answers

Which of the following is NOT a type of non-keratinocyte found in the epithelial layer?

Fibroblasts Signup and view all the answers

Which clinical consideration relates to pigmentation of oral mucosa?

Physiologic, racial, and pathologic pigmentation Signup and view all the answers

What type of cells primarily compose taste buds?

Neuroepithelial cells Signup and view all the answers

Which cranial nerve is responsible for taste sensation in the anterior two-thirds of the tongue?

N VII (Facial nerve) Signup and view all the answers

What is the primary structural feature of taste buds?

Barrel-shaped clusters Signup and view all the answers

Which part of the tongue detects bitter taste?

Posterior 1/3 Signup and view all the answers

What connective tissue structures are present in the lip?

Striated muscles and minor salivary glands Signup and view all the answers

Where are taste buds NOT typically found?

On the ventral surface of the tongue Signup and view all the answers

What are the basic taste sensations detected by taste buds?

Sweet, salty, sour, bitter Signup and view all the answers

What is the primary function of filiform papillae on the tongue?

Abrasive surface for food manipulation Signup and view all the answers

In which of the following regions do taste buds organize into barrel-shaped clusters?

Lateral wall of foliate papillae Signup and view all the answers

Which section of the tongue is primarily covered by masticatory mucosa?

Anterior 2/3 Signup and view all the answers

Circumvallate papillae are characterized by which of the following features?

Large with a deep circular groove surrounding them Signup and view all the answers

Fungiform papillae exhibit which distinctive characteristic?

Scattered between filiform papillae and contain taste buds Signup and view all the answers

What anatomical feature divides the tongue into anterior 2/3 and posterior 1/3?

Sulcus terminalis Signup and view all the answers

Which type of papillae may be found on the lateral aspects of the human tongue and can contain taste buds?

Foliate papillae Signup and view all the answers

What type of minor salivary glands open into the sulcus of circumvallate papillae?

Von Ebner serous glands Signup and view all the answers

Which statement accurately describes the keratinization of the mucosa on circumvallate papillae?

Keratinised overlying non-keratinised mucosa on lateral borders Signup and view all the answers

Study Notes

Oral Mucosa Composition

Oral mucosa is comprised of two layers: epithelium and lamina propria.
The basement membrane separates the epithelium and lamina propria.
Rete ridges and connective tissue papillae interdigitate.

Oral Mucosa Types

Lining mucosa consists of epithelium, lamina propria, and submucosa.
Specialized mucosa consists of epithelium, lamina propria, and submucosa.
Masticatory mucosa consists of epithelium, lamina propria, periosteum, and bone.

Epithelium Composition

Keratinocytes are squamous epithelial cells that contribute to the keratinization process.
Non-keratinocytes include melanocytes, Langerhans cells, Merkel cells, and inflammatory cells.

Keratinocytes

Keratinocytes are filled with cytokeratin.
Hyperkeratosis is an increase in thickness of epithelial tissue due to keratinocyte activity.
Linea alba is a thin keratin layer formed along the occlusal line of the non-keratinized buccal mucosa.
Inflammation can reduce keratinization to the point where it appears parakeratinized or non-keratinized.

Non-Keratinocytes

Non-keratinocytes comprise 10% of the cells in the epithelial layer.
Melanocytes produce melanin in melanosomes and transfer it to keratinocytes.
Langerhans cells act as antigen-presenting cells for immune function.
Merkel cells are found in the basal layer, near nerve fibers, and contribute to touch sensation.

Clinical Considerations for Pigmentation

Pigmentation of the oral mucosa can be physiologic (racial or genetic) or pathologic (neoplastic, such as melanoma).
Albinism occurs due to a lack of tyrosinase, resulting in hypopigmentation and visual impairments.

Tongue Papillae

Filiform papillae are hair-like structures that cover the anterior 2/3 of the tongue.
Fungiform papillae are mushroom-shaped and scattered among filiform papillae, containing taste buds.
Foliate papillae may contain taste buds and are located on the lateral tongue.
Circumvallate papillae have a deep circular groove surrounding them, with taste buds on the lateral borders.
Von Ebner’s glands secrete serous fluid into the sulcus of circumvallate papillae.

Taste Buds

Taste buds are chemoreceptor organs for taste, containing modified epithelial cells called neuroepithelial cells.
Taste buds are renewed by differentiation from surrounding epithelium.
Taste buds are found on the lateral walls of circumvallate and foliate papillae, the upper surface of fungiform papillae, the soft palate, and the epiglottis.

Taste Bud Histology

Taste buds are barrel-shaped clusters of 30-80 spindle-shaped cells.
Taste buds extend from the basal lamina to the free surface of the epithelium.
The taste pore is sealed from the oral cavity allowing substances to absorb to the microvilli surface.

Neural Innervation

Anterior 2/3 of the tongue: Facial nerve (CN VII).
Posterior 1/3, circumvallate and foliate papillae: Glossopharyngeal nerve (CN IX).
Soft palate: Greater Petrosal nerve of the Facial nerve (CN VII).
Pharynx and epiglottis: Vagus nerve (CN X).

Taste

Four basic tastes: sweet, salty, bitter, and sour.
Taste sensitivity varies depending on the location of the taste bud.

Lip

The lip has skin on the outer surface and labial mucosa on the inner surface.
The vermilion zone (red zone) separates the skin and the labial mucosa.
The submucosa contains minor mucous salivary glands.

Lip Composition

Skin: dermis and epidermis with a flat border between them.
Connective tissue: sweat glands, sebaceous glands, and bases of hair follicles.

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Description

Explore the intricate structures and functions of the oral mucosa, including its various types and the role of keratinocytes in maintaining oral health. This quiz covers the composition of the epithelium and lamina propria, highlighting important cellular structures and their significance.