Lingual Glands Anatomy

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Questions and Answers

What type of epithelia is found in excretory ducts?

Cuboidal

Squamous

Pseudostratified or stratified (correct)

Simple columnar

Which gland is located between muscle fibers, below the circumvallate and foliate papillae?

Submandibular gland

Von Ebner gland (correct)

Weber gland

Blandin-Nuhn gland

What is the function of the secretion of Von Ebner gland?

Moisturizing the food

Washing out the trough of papillae and readying the taste receptors for a new taste stimulus (correct)

Breaking down carbohydrates

Regulating body temperature

Which glands are associated with the lingual tonsils?

Weber glands Signup and view all the answers

What is the composition of saliva?

99% of water and 1% of organic and inorganic substances Signup and view all the answers

What are the two components of salivary glands?

Epithelial tissue and connective tissue Signup and view all the answers

What type of cells are involved in the secretion of thin, watery, and proteinaceous substances?

Serous cells Signup and view all the answers

Which gland secretes the majority of saliva?

Submandibular gland Signup and view all the answers

Where do terminal secretary units drain into?

Intercalated ducts Signup and view all the answers

What is the function of enzymes in saliva?

Protecting the oral cavity from bacterial infections Signup and view all the answers

Where do the ducts of Weber glands open?

Dorsal surface of the tongue through the lingual crypts Signup and view all the answers

What is the function of the Golgi complex in serous cells?

Protein modification and packaging Signup and view all the answers

What is the significance of intercellular canaliculi in serous cells?

Increases the surface area for secretion Signup and view all the answers

What is the characteristic shape of serous cells under light microscopy?

Pyramidal Signup and view all the answers

What is the size of the secretory granules in the apical cytoplasm of serous cells?

1µm Signup and view all the answers

What type of protein is found in the secretory granules of serous cells?

Glycoprotein Signup and view all the answers

What is the main function of the ductal system in salivary glands?

Modification and secretion of saliva Signup and view all the answers

What type of cells line the intercalated ducts?

Cuboidal cells Signup and view all the answers

What is the characteristic feature of striated ducts under electron microscopy?

Presence of prominent striations at the basal part of cells Signup and view all the answers

What is the role of striated ducts in saliva secretion?

Reabsorption of water and electrolytes Signup and view all the answers

What type of cells are present in terminal excretory ducts near striated ducts?

Pseudostratified tall columnar cells Signup and view all the answers

Where are terminal excretory ducts located?

Interlobular location Signup and view all the answers

What is the function of the striated border in striated ducts?

Acts as a sodium pumping machine Signup and view all the answers

What type of ducts merge with oral epithelium at the duct orifice?

Terminal excretory ducts Signup and view all the answers

Study Notes

Excretory Ducts and Lingual Glands

Excretory ducts have pseudostratified or stratified epithelia.
Anterior lingual glands are also known as Blandin-Nuhn glands, located at the tip of the tongue, ventral surface, and lingual frenum.
Posterior lingual glands consist of Von Ebner gland and Weber gland.

Von Ebner Gland

Located between muscle fibers, below the circumvallate and foliate papillae.
Functions include washing out the trough of papillae and readying taste receptors for a new taste stimulus, and contains antibacterial and lipolytic enzymes for protective and digestive purposes.

Weber Glands

Located in the posterior one-third of the tongue, associated with lingual tonsils.
Ducts open on the dorsal surface of the tongue through lingual crypts.

Composition of Saliva

99% water and 1% of organic and inorganic substances.
Organic substances include enzymes, mucins, and antibacterial substances, with minor quantities of albumin, blood clotting factor, and immunoglobulin IgA.
Inorganic substances include sodium, chloride, bicarbonate, and smaller amounts of calcium, magnesium, phosphate, iodine, thiocyanate, and fluoride.

Volume of Saliva

Majority is secreted by the submandibular gland, followed by the parotid and sublingual glands.
The least amount is secreted by minor salivary glands.

Functions of Saliva

Not specified in the provided text, but salivary gland histology and function will be discussed later.

Structure of Salivary Glands

Composed of epithelial and connective tissue components.
The epithelial component is called parenchyma, supported by connective tissue.

Secretory Units

Consist of serous cells, mucous cells, and myoepithelial cells.

Duct System

Consists of intercalated ducts, striated ducts, and terminal excretory ducts.
Terminal secretary units drain into ducts, which are then divided into intercalated ducts, striated ducts, and finally, excretory ducts that open into the oral cavity.

Component of Terminal Secretory Units

Serous cells secrete thin, watery, and proteinaceous substances.
Mucous cells secrete mucins.

Serous Cells/Serous Acini

Pyramidal in shape, with spherical nuclei located basally.
Contain numerous secretory granules in the apical cytoplasm.
8-12 cells surround a central lumen, with cytoplasm intensely stained with H & E and nucleus stained with hematoxylin.

Electron Microscopy of Serous Cells

Protein-secreting cell with a central lumen and intercellular canaliculi.
Large amounts of RER are placed basally and laterally to the nucleus.
Prominent Golgi complex is located just apical or lateral to the nucleus.
Apical cytoplasm is filled with secretory granules that are +ve for PAS Stain.

Ductal System and Ductal Modification

The ductal system is responsible for production and modification of saliva.
It consists of three types of ducts: intercalated, striated, and terminal ducts.

Intercalated Ducts

Lined by a single layer of low cuboidal cells.
Contain a few secretory granules, with a round/oval centrally placed nucleus and empty-appearing cytoplasm.
Small amounts of RER are located in the basal cytoplasm.

Striated Ducts

Lined by columnar cells with a central placed nucleus.
Pale, acidophilic cytoplasm.
Electron microscopy shows prominent striations at the basal part of cells, numerous elongated mitochondria in narrow cytoplasmic, and few rER and Golgi complexes around the nucleus.
Luminal surface has microvilli, and desmosomal attachment is present.

Function of Striated Ducts

Involved in secretion and reabsorption of water and electrolytes.
Striated border acts as a sodium-pumping machine, reabsorbing sodium and chloride, and secreting potassium and bicarbonate ions to make isotonic secretion to hypotonic secretion.

Terminal Excretory Ducts

Located in connective tissue septa, i.e., an extra-lobular location.
Larger in diameter than striated ducts.
Near striated duct, pseudostratified tall columnar cells are admixed with small basal cells and goblet cells.
Tall columnar cells merge with oral epithelium at the duct orifice.

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Description

This quiz covers the different types of lingual glands, including anterior and posterior glands, and their locations in the tongue. It also discusses the Von Ebner gland and its function.