Salivary Glands Overview
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Questions and Answers

What is the primary type of secretion produced by the parotid gland in adults?

  • Serous (correct)
  • Mucous
  • Mixed
  • Viscous

    • Where is the submandibular gland located?

  • Angle of the mandible (correct)
  • In the cheek
  • Under the tongue
  • Behind the ear

    • What percentage of saliva secretion is attributed to the sublingual gland?

  • 60%
  • 90%
  • 5% (correct)
  • 25%

    • Which duct is associated with the submandibular gland?

    <p>Wharton's duct</p> Signup and view all the answers

    What is the main function of the mucin produced by saliva?

    <p>Lubrication</p> Signup and view all the answers

    How much of the saliva composition is water?

    <p>99%</p> Signup and view all the answers

    What type of gland is primarily found in the minor salivary glands?

    <p>Mucous</p> Signup and view all the answers

    Which of the following glands is known for having serous glands of von Ebner?

    <p>Minor salivary glands</p> Signup and view all the answers

    What type of secretion is primarily produced by the parotid gland in adults?

    <p>Pure serous</p> Signup and view all the answers

    Which of the following glands is not encapsulated?

    <p>Sublingual gland</p> Signup and view all the answers

    How many types of salivary glands are classified according to size?

    <p>Two: Major and Minor</p> Signup and view all the answers

    What is the main duct for the submandibular gland?

    <p>Wharton's duct</p> Signup and view all the answers

    Which type of secretion predominates in the sublingual gland?

    <p>Mixed (mostly mucous)</p> Signup and view all the answers

    What distinguishes merocrine glands from other types of glands?

    <p>Only the secretion of the cell is released</p> Signup and view all the answers

    Which of the following is a minor salivary gland?

    <p>Buccal gland</p> Signup and view all the answers

    Where are salivary glands not present?

    <p>Dorsum of the anterior two-thirds of the tongue</p> Signup and view all the answers

    What feature distinguishes mucous cells from other cell types based on their Golgi apparatus?

    <p>They have a more developed Golgi apparatus.</p> Signup and view all the answers

    What is a primary function of myoepithelial cells?

    <p>To support the underlying parenchyma.</p> Signup and view all the answers

    Which of the following describes the nuclei of intercalated duct cells?

    <p>Prominent and centrally located.</p> Signup and view all the answers

    Which characteristic is associated with striated ducts?

    <p>Form a longer and more active component than intercalated ducts.</p> Signup and view all the answers

    How do myoepithelial cells contribute to salivary flow?

    <p>By contributing to secretory pressure.</p> Signup and view all the answers

    What type of epithelial cells line the intercalated ducts?

    <p>Simple cuboidal epithelial cells.</p> Signup and view all the answers

    What is notable about the basal membrane of striated ducts?

    <p>It exhibits distinct striation.</p> Signup and view all the answers

    Which of the following statements about myoepithelial cells is false?

    <p>They only have connections with duct cells.</p> Signup and view all the answers

    What distinguishes oncocytes from other parenchymal cells?

    <p>Their coexpression of cytokeratin 14 and bcl-2, along with a high proliferative index.</p> Signup and view all the answers

    What histological change in salivary glands increases with age?

    <p>Increase in oncocytes and fibrous tissue.</p> Signup and view all the answers

    Which duct is responsible for resorption and secretion of electrolytes?

    <p>Striated duct.</p> Signup and view all the answers

    What is a potential stem cell in salivary glands?

    <p>Myoepithelial cells.</p> Signup and view all the answers

    What characteristic do oncocytes exhibit?

    <p>They are granular and acidophilic due to an increase in mitochondria.</p> Signup and view all the answers

    What is the main function of the striated ducts in salivary glands?

    <p>Electrolyte resorption and secretion</p> Signup and view all the answers

    Which gland typically has intercalated ducts that are shorter and harder to locate?

    <p>Submandibular gland</p> Signup and view all the answers

    What is the effect of striated ducts on the composition of saliva?

    <p>Turns isotonic or slightly hypertonic fluid into a hypotonic fluid</p> Signup and view all the answers

    What type of cells are commonly found in the parotid gland and what do they contain?

    <p>Serous cells containing neutral glycoproteins</p> Signup and view all the answers

    What occurs in the minor salivary glands in relation to striated ducts?

    <p>They do not have intercalated ducts</p> Signup and view all the answers

    What happens to the sodium content in saliva secreted from minor salivary glands?

    <p>It remains unchanged</p> Signup and view all the answers

    What distinguishes the intercalated ducts from the striated ducts in the salivary glands?

    <p>Intercalated ducts are shorter and less numerous</p> Signup and view all the answers

    Which salivary gland typically lacks striated ducts altogether?

    <p>Sublingual gland</p> Signup and view all the answers

    Study Notes

    Salivary Glands

    • Salivary glands are exocrine glands comprised of tubules that open into the oral cavity
    • Classified as compound tubuloacinar merocrine glands
    • Can be major (parotid, submandibular, sublingual) or minor (scattered throughout oral mucosa)
    • Classified by secretion type: mucous, serous, or mixed
    • Not present in gingiva or the dorsal part of the anterior two-thirds of the tongue

    Parotid Gland

    • Largest salivary gland
    • Secretes 25% of total saliva, mainly serous in adults
    • Mixed serous secretion in infants and older adults
    • Stenson's duct is the main duct
    • Has a capsule with fat cells spaces

    Submandibular Gland

    • Located at the angle of the mandible
    • Second largest salivary gland: secretes 60% of total saliva
    • Mixed secretion, predominantly serous
    • Has a well-formed connective tissue capsule
    • Wharton's duct is the main duct

    Sublingual Gland

    • Located on the anterior floor of the mouth, secretes 5% of total saliva
    • Mixed secretion, predominantly mucous
    • Poorly encapsulated or non-encapsulated
    • Bartholin's duct is the main duct, 8 to 30 smaller ducts open directly into the oral mucosa

    Minor Salivary Glands

    • Scattered throughout oral mucosa
    • Contribute 5 - 10% of total saliva
    • Mostly mucous, except for serous glands of von Ebner associated with circumvallate papillae
    • Types:
      • Palatoglossal glands: pharyngeal isthmus
      • Palatal glands: hard and soft palate
      • Anterior lingual glands: near ventral surface of the tongue
      • Posterior lingual glands: root of the tongue

    Saliva Composition

    • Over 99% water
    • Small amounts of inorganic and organic compounds including proteins, glycoproteins and enzymes
    • Functions:
      • Lubrication: mucin acts as lubricant during mastication, swallowing, and speech
      • Taste: dissolves substances for taste perception

    Myoepithelial cells

    • Located between acinar and intercalated duct cells
    • Contribute to salivary flow by:
      • Supporting acinar parenchyma
      • Accelerating initial saliva outflow
      • Reducing luminal volume
      • Contributing to secretory pressure
      • Overcoming peripheral resistance
    • Structure:
      • Dendritic: stellate shape with radiating processes around acini
      • Elongated, Longitudinal: short processes around intercalated ducts
    • Contraction triggered by parasympathetic and sympathetic stimulation
    • Possess numerous actin microfilaments

    Duct System

    • Intralobular (within lobule):

      • Intercalated ducts:
        • Smallest and most distal, drain several acini
        • Lined by cuboidal epithelial cells with secretory granules
        • Modify saliva by adding lysozyme and lactoferrin
      • Striated ducts:
        • Longer and more active than intercalated ducts
        • Lined by simple columnar epithelium
        • Involved in active transport due to high mitochondrial content
        • Secrete epidermal growth factor, lysozyme, kallikrein and IgA

    • Interlobular (between lobules):

      • Collecting ducts:
        • Transport saliva; function as collecting ducts
        • Lined by columnar epithelium (may be bi-layered)
        • Have a connective tissue adventitia
        • Merge with stratified squamous epithelium of oral mucosa

    • Duct System Comparison Across Salivary Glands:*

    • Parotid: Long and branching intercalated and striated ducts

    • Submandibular: Shorter intercalated ducts and longer, more obvious striated ducts; less numerous than in parotid

    • Sublingual: Less developed duct system; striated ducts usually absent

    • Minor: Collecting ducts present, intercalated and striated ducts generally absent

    Salivary Glycoproteins

    • Mixture of salivary glycoproteins ranging from neutral to acidic
    • Serous cells in the parotid gland contain neutral glycoproteins

    Oncocytes

    • Epithelial cells found singly or in small groups within acini and ducts
    • Characterized by numerous mitochondria, reducing other organelles
    • Appear acidophilic and granular
    • Increase in number with age, likely due to degeneration of normal cells

    Age Changes

    • Decrease in glandular tissue (number of secretory cells)
    • Increase in fibrous tissue, fat cells, inflammatory cells, and oncocytes
    • Increase in duct volume
    • Hyposalivation ("xerostomia")
    • Lymphocytic foci infiltration

    Key Points

    • Salivary glands are classified based on size and secretion type.
    • The parotid gland is the largest, secreting mostly serous saliva.
    • The submandibular gland is second largest, secreting a mixed serous and mucous saliva.
    • The sublingual gland is the smallest, secreting mostly mucous saliva.
    • Myoepithelial cells help regulate saliva flow and contribute to secretory pressure.
    • The duct system modifies saliva composition.
    • Striated ducts are the site of electrolyte resorption and secretion.
    • Salivary glycoproteins can vary in their acidity.
    • Oncocytes are characterized by an abundance of mitochondria and increase with age.
    • Age-related changes in salivary glands can include hyposalivation and increased lymphocytic foci.

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    Description

    This quiz covers the anatomy and functions of salivary glands, including major glands like the parotid, submandibular, and sublingual. Learn about their structure, secretion types, and associated ducts. Perfect for students studying human anatomy and physiology.

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