Wheater's Functional Histology: Mucosa and Muscularis Layers

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the characteristic of the filiform type of papillae?

Rounded and non-keratinized

Flat and moderately keratinized

Mushroom-shaped and lightly keratinized

Pointed and heavily keratinized (correct)

What is the function of the basal cells in the taste buds?

They support the sensory cells

They are responsible for the sense of smell

They regenerate the sensory and supporting cells (correct)

They extend microvilli into the taste pore

What is the name of the type of epithelium that covers the papillae?

Pseudostratified epithelium

Simple columnar epithelium

Cuboidal epithelium

Stratified squamous epithelium (correct)

Where are the taste buds found in the tongue?

In the fungiform, circumvallate and foliate papillae Signup and view all the answers

What is the shape of the taste buds in histological sections?

Ovoid Signup and view all the answers

What is the function of the microvilli in the sensory cells?

They contain the receptors for the basic taste modalities Signup and view all the answers

What is the location of the small salivary glands in the tongue?

In the connective tissue of the tongue Signup and view all the answers

What is the number of cells typically found in a taste bud?

50-75 cells Signup and view all the answers

What is the shape of fungiform papillae?

Mushroom-shaped Signup and view all the answers

What is the number of circumvallate papillae in humans?

Between 8 and 12 Signup and view all the answers

Where are the taste buds located on the circumvallate papillae?

On the lateral surfaces of the papillae Signup and view all the answers

What is the function of the serous glands opening into the trenches surrounding the circumvallate papillae?

To flush the cleft, renewing the fluid in contact with the taste buds Signup and view all the answers

What is the characteristic of the surface of the tongue where the circumvallate papillae occur?

Depressions of the surface Signup and view all the answers

What is the characteristic of the foliate papillae in adults?

Poorly developed Signup and view all the answers

What is the distribution of the taste buds on the fungiform papillae?

Scattered on their upper surfaces Signup and view all the answers

What is the characteristic of the micrograph of a circumvallate papilla?

Many taste buds around the sides and several small salivary glands Signup and view all the answers

What type of epithelium covers the soft palate, lips, cheeks, and the floor of the mouth?

Nonkeratinized squamous epithelium Signup and view all the answers

What is found in the submucosa of the soft palate?

Diffuse small salivary glands Signup and view all the answers

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

To provide a rough surface for food movement Signup and view all the answers

What is the shape of the filiform papillae on the tongue?

Conical Signup and view all the answers

What is the epithelium of the filiform papillae on the tongue?

Keratinized Signup and view all the answers

What is the characteristic of the tongue's dorsal surface?

It is irregular and has many small eminences called papillae Signup and view all the answers

What is the boundary between the anterior two-thirds and the posterior one-third of the tongue's dorsal surface?

The terminal sulcus Signup and view all the answers

What is found on the surface of the root of the tongue?

Lingual tonsils Signup and view all the answers

What type of muscle cells are found in the muscularis layer of the digestive tract?

Smooth muscle cells Signup and view all the answers

What is the main function of the epithelial lining of the digestive tract?

To provide a selectively permeable barrier between the contents of the tract and the tissues of the body Signup and view all the answers

What type of epithelium lines the oral cavity?

Stratified squamous epithelium Signup and view all the answers

What type of muscle fibers are found in the middle third of the oesophagus?

A combination of skeletal and smooth muscle fibers Signup and view all the answers

What is the function of the keratin layer in the oral cavity?

To protect the oral mucosa from damage during masticatory function Signup and view all the answers

What type of muscle fibers are found in the distal third of the oesophagus?

Only smooth muscle fibers Signup and view all the answers

What is the outermost layer of the digestive tract?

Serosa/Adventitia Signup and view all the answers

What type of tissue covers the oesophagus in the peritoneal cavity?

Serosa Signup and view all the answers

What is the function of the arrangement of the oesophageal mucosa?

To allow marked distension during the passage of a food bolus Signup and view all the answers

What is the function of the lamina propria in the oral cavity?

To support the epithelial layer Signup and view all the answers

What is the function of mucosa in the digestive tract?

To provide a selectively permeable barrier between the contents of the tract and the tissues of the body Signup and view all the answers

What type of epithelium lines the lumen of the oesophagus?

Stratified squamous epithelium Signup and view all the answers

What is the function of the submucosa in the digestive tract?

To support the mucosa Signup and view all the answers

What is the function of the seromucous glands in the submucosa?

To aid lubrication during the passage of a food bolus Signup and view all the answers

What is the arrangement of the muscularis propria in the oesophagus?

Inner circular and outer longitudinal layers of smooth muscle Signup and view all the answers

Why are bundles of skeletal muscle present in the upper third of the oesophagus?

Because the first part of swallowing is under voluntary control Signup and view all the answers

Study Notes

Digestive Tract

The digestive tract has four layers: mucosa, muscularis, submucosa, and serosa/adventitia
Mucosa supports the mucosa, composed of epithelium, lamina propria, and muscularis mucosae
Muscularis is thick and composed of smooth muscle cells, divided into two sublayers: internal (circular) and external (longitudinal)
Serosa/Adventitia is a thin outer layer of loose connective tissue, rich in blood vessels, lymphatics, and adipose tissue

Functions of the Epithelial Lining

Provides a selectively permeable barrier between the contents of the tract and the tissues of the body
Facilitates the transport and digestion of food
Promotes the absorption of the products of digestion
Produces hormones that affect the activity of the digestive system
Produces mucus for lubrication and protection

Oral Cavity

The oral cavity is lined with stratified squamous epithelium, which is keratinized or nonkeratinized depending on the region
The keratin layer protects the oral mucosa from damage during masticatory function and is best developed on the gingiva and hard palate
The lamina propria in these regions has many papillae and rests directly on bony tissue

Tongue

The tongue is a mass of striated muscle covered by a mucous membrane whose structure varies according to the region
The muscle fibers cross one another in three planes and are grouped in bundles separated by connective tissue
The tongue's dorsal surface is irregular, covered anteriorly by small eminences called papillae

Papillae of Tongue

Filiform papillae: smallest and most numerous, conical shape, epithelium does not contain taste buds and is keratinized
Fungiform papillae: less numerous, lightly keratinized, mushroom-shaped with connective tissue cores and scattered taste buds on their upper surfaces
Circumvallate papillae: largest and least numerous, occur in depressions of the surface of the tongue, surrounded by a trench formed by the infolding of the epithelium
Foliate papillae: poorly developed in adults, consist of parallel ridges and furrows on the sides of the tongue, contain many taste buds

Taste Buds

Taste buds are ovoid/onion-shaped structures containing 50-75 cells, resting in the basal lamina
Taste buds are most numerous in the fungiform, circumvallate, and foliate papillae
In addition, taste buds are found in the palate, palatoglossal and palatopharyngeal arches, and in the pharynx and larynx
Taste buds contain sensory cells, supporting cells, and basal cells
Sensory cells extend microvilli into the taste pore, which contain the receptors for the different basic taste modalities

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Learn about the mucosa, muscularis, and serosa/adventitia layers in Wheater's functional histology. Understand their composition, structure, and functions.