LEC 1 histo

What are the three main zones of the lip?

Outer surface (skin), inner surface (mucous membrane), and vermilion zone (lip margin)

Describe the epithelium of the vermilion zone.

Very thin keratinized stratified squamous epithelium.

A patient presents with a dry, cracked lip. Which zone of the lip is likely affected, and why?

The vermilion zone, because it has no sweat or salivary glands and relies on saliva for moisture.

Compare the connective tissue of the inner surface of the lip to the vermilion zone.

The inner surface has loose connective tissue, while the vermilion zone has connective tissue rich in sensory nerves and blood capillaries.

How does the structure of the tongue's mucous membrane contribute to its function?

The dense collagenous connective tissue (lamina propria) strongly adheres to the underlying muscular core, facilitating movement.

What are the two main areas of the tongue's dorsal surface and how do they differ?

The anterior two-thirds (papillary area) has lingual papillae, while the posterior third (tonsillar area) has lingual tonsils and no papillae.

What are the four types of lingual papillae?

Filiform, fungiform, foliate, and circumvallate.

Which type of lingual papillae is most numerous and what is its primary function?

Filiform papillae, which provide a rough surface for movement of food during chewing.

A patient reports a loss of taste. Damage to which lingual papillae could cause this?

Damage to fungiform, foliate or circumvallate papillae could cause taste issues, as they contain taste buds.

Compare and contrast the structure and function of filiform and circumvallate papillae.

Filiform are heavily keratinized, lack taste buds, and aid in food movement; circumvallate are non-keratinized, contain numerous taste buds, and have von Ebner glands.

Based on your understanding of the structure, justify why von Ebner's glands are located near the circumvallate papillae.

Their watery secretion dissolves food, which facilitates taste reception, since the circumvallate papillae have the most taste buds and are most important for taste.

How would you classify taste buds in terms of their function and structure?

Chemoreceptors for taste, consisting of gustatory cells, supporting cells, and basal cells, with microvilli projecting into the taste pore.

Where are the majority of taste buds located in humans?

Primarily on the lateral surface of the circumvallate papillae.

If a drug inhibits taste bud turnover, what specific cells would be affected and why?

Basal cells would be affected as they are responsible for taste cell and supporting cell turnover.

What is the Waldeyer ring, and what is its function?

It is composed of the palatine, lingual, and adenoid tonsils and guards the entrance to the gastrointestinal and respiratory tracts.

Describe the general structure of a salivary gland.

Stroma (capsule, septa, reticular network) and parenchyma (secretory acini, branching ducts).

What are the three main types of salivary acini?

Serous, mucous, and mixed (seromucous).

Compare and contrast serous and mucous acini in terms of their cell structure and function.

Serous cells are protein-secreting, pyramidal with basophilic cytoplasm, while mucous cells secrete mucins, are low columnar with pale cytoplasm.

How do myoepithelial cells contribute to salivary gland function?

They contract to squeeze the acini and expel secretions.

What is the function of striated ducts in salivary glands?

They reabsorb sodium ions, making saliva hypotonic.

A patient presents with dry mouth due to a salivary duct issue. Which specific type of duct might be dysfunctional to cause this and why?

The striated ducts, as they modify saliva's ion content, and dysfunction can lead to reduced saliva secretion.

How do the structures of the intercalated and striated ducts relate to their functions?

Intercalated ducts are simple squamous/cuboidal for initial transport; striated ducts have basal infoldings and mitochondria for ion transport.

Describe the structure and function of the parotid gland.

It is a pure serous gland that secretes α-amylase and proline-rich proteins.

Compare the secretions of the submandibular and sublingual glands.

Submandibular is mainly serous (α-amylase, lysozyme), while sublingual is mainly mucus, with some serous secretions (amylase, lysozyme).

Design a treatment plan for someone with a deficiency in proline rich proteins. Which glands and enzymes should be targetted?

The parotid gland and to a lesser extent the submandibular gland, which secretes proline-rich proteins, and should focus on drugs that will improve secretion.