Anatomy of the Tongue

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Questions and Answers

What is the function of the tongue during mastication and swallowing?

To manipulate ingested material

What type of epithelial lining is found on the ventral surface of the tongue?

Non-keratinized stratified squamous epithelial

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

To facilitate movement of food during chewing

What is the characteristic of fungiform papillae on the tongue?

They are lightly keratinized Signup and view all the answers

Where are the foliate papillae located on the tongue?

On the lateral surface of the tongue, anterior to the sulcus terminalis Signup and view all the answers

What is the purpose of the ducts of the Von Ebner glands?

To wash away food particles from the taste buds Signup and view all the answers

How many vallate papillae are normally found on the tongue?

8-12 Signup and view all the answers

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

It is irregular and keratinized Signup and view all the answers

Match the type of cells found in taste buds with their descriptions:

Type I = Receptor cells Type II = Glial-like cells Type III = Presynaptic cells Type IV = Gustatory epithelial/basal cells Signup and view all the answers

Match the parts of the esophagus with their descriptions:

Mucosa = Contains epithelium, lamina propria, and muscular layer Submucosa = Contains dense irregular connective tissue Muscularis mucosae = Contains longitudinal smooth muscle fibers Lumen = Has a branched appearance due to longitudinal folds Signup and view all the answers

Match the structures found in the esophagus with their locations:

Mucosal esophageal glands = Near the junction with the stomach Submucosal plexus = In the submucosa Submucosal esophageal glands = In the submucosa Ganglion cells = In the submucosa Signup and view all the answers

Match the types of papillae with their characteristics:

Vallate papillae = Have approximately 250 taste buds on their lateral surface Fungiform papillae = Have many taste buds on their surface Foliate papillae = Do not have taste buds on their surface Filiform papillae = Have no taste buds on their surface Signup and view all the answers

Match the parts of the esophageal wall with their compositions:

Epithelium = Non-keratinized stratified squamous epithelium Lamina propria = Contains mucosal esophageal glands Muscular layer = Contains longitudinal smooth muscle fibers Muscularis mucosae = Contains longitudinal smooth muscle fibers Signup and view all the answers

Match the structures found in the gastrointestinal tract with their locations:

Taste buds = On the lateral surface of vallate papillae and in the upper esophagus Vallate papillae = On the back of the tongue Esophagus = Delivers food and liquids from the pharynx to the stomach Foliate papillae = On the back of the tongue Signup and view all the answers

Match the functions of esophageal structures with their descriptions:

Mucosal esophageal glands = Secrete neutral mucus to protect the esophagus Submucosal esophageal glands = Secrete mucus to aid in swallowing Taste buds = Sample the general chemical composition of ingested material Esophagus = Delivers food and liquids from the pharynx to the stomach Signup and view all the answers

Match the characteristics of the esophagus with their descriptions:

Length = Approximately 25 cm Lumen = Has a branched appearance due to longitudinal folds Muscular layer = Contains longitudinal smooth muscle fibers Esophageal glands = Secrete mucus to aid in swallowing Signup and view all the answers

Match the types of cells found in taste buds with their functions:

Type I = Glial-like cells Type II = Receptor cells Type III = Presynaptic cells Type IV = Gustatory epithelial/basal cells Signup and view all the answers

Match the structures found in the esophagus with their functions:

Mucosa = Protects the esophagus from regurgitated stomach contents Submucosa = Contains nerve fibers and ganglion cells Muscularis mucosae = Aids in peristalsis Esophageal glands = Secrete mucus to aid in swallowing Signup and view all the answers

Study Notes

Structure of the Tongue

The tongue is a mass of striated muscle covered by mucosa, which manipulates ingested material during mastication and swallowing.
A connective tissue between the small fascicles of muscle is penetrated by the lamina propria, making the mucous membrane strongly adherent to the muscular core.

Surface of the Tongue

The ventral surface of the tongue is smooth, with a non-keratinized stratified squamous epithelial lining.
The dorsal surface is irregular, lined with keratinized stratified squamous epithelial and featuring hundreds of small protruding papillae of various types on its anterior two-thirds and the massed lingual tonsils on the posterior third, or root of the tongue.

Types of Lingual Papillae

There are four types of lingual papillae: filiform, fungiform, foliate, and vallate (or circumvallate) papillae.
Filiform Papillae: numerous, elongated conical shape, heavily keratinized, and provide a rough surface for food movement during chewing.
Fungiform Papillae: less numerous, lightly keratinized, mushroom-shaped, and have well-vascularized and innervated cores of lamina propria.
Foliate Papillae: consist of several parallel ridges on the lateral surface of the tongue, anterior to the sulcus terminals.
Vallate (or Circumvallate) Papillae: the largest papillae, with diameters of 1 to 3 mm, and are aligned just in front of the terminal sulcus; ducts of several small serous salivary (Von Ebner) glands empty into the deep groove surrounding each vallate papilla, providing a continuous flow of fluid over the taste buds.

Taste Buds

Microscopic sensory organs containing chemosensory cells that synapse with afferent fibers of gustatory nerves
Oval, pale-staining structures that extend through the epithelium, sampling the general chemical composition of ingested material
Four types of cells found in taste buds:
- Type I (glial-like) gustatory epithelial cells
- Type II (receptor) gustatory epithelial cells
- Type III (presynaptic) gustatory epithelial cells
- Type IV gustatory epithelial/basal cells
Approximately 250 taste buds present on the lateral surface of each vallate papilla
Also found in the uppermost parts of the gastrointestinal tract, including the soft palate, epiglottis, oropharynx, and upper esophagus

The Esophagus

Fixed muscular tube delivering food and liquids from the pharynx to the stomach
Approximately 25 cm in length
Lumen has a branched appearance due to longitudinal folds in its normally collapsed state
Lumen expands without mucosal injury when a bolus passes through
Histological layers:
- Mucosa: non-keratinized stratified squamous epithelium, lamina propria, and muscular layer
- Submucosa: dense irregular connective tissue with blood and lymphatic vessels, nerve fibers, and ganglion cells
- Muscularis mucosae: longitudinal smooth muscle fibers
- Adventitia/serosa: covered by adventitia in the thoracic part and serosa in the abdominal part

Gastroesophageal Reflux Disease (GERD)

Lubricating mucus produced in the esophagus offers little protection against acid from the stomach
Incompetent inferior esophageal sphincter may result in chronic heartburn, leading to erosion of the esophageal mucosa or GERD
Untreated GERD can produce metaplastic changes (Barrett's syndrome)