Salivary Glands and Their Functions

Introduction

• Salivary glands are exocrine glands in the mouth that produce saliva.
• Saliva contains water, electrolytes, enzymes, and mucus.
• Saliva plays a critical role in digestion, lubrication, and oral health.
• Three major pairs of salivary glands: parotid, submandibular, and sublingual.
• Numerous minor salivary glands are found throughout the oral cavity.

Functions of Saliva

• Lubrication: Saliva moistens and lubricates the food bolus, facilitating swallowing.
• Digestion: Saliva contains enzymes like amylase, which begins the chemical breakdown of carbohydrates.
• Protection: Saliva helps maintain oral hygiene by washing away food debris and bacteria. It also contains antimicrobial substances that inhibit bacterial growth. Prevents tooth decay and other oral diseases.
• Taste: Saliva dissolves food particles, allowing taste receptors to detect flavors.
• Buffering: Saliva neutralizes acids, protecting teeth from erosion.

Salivary Gland Types

• Parotid glands: Largest salivary glands, located anterior to the ear.
  • Secrete a serous fluid rich in amylase.
  • Stenson's duct opens into the oral cavity opposite the second upper molar.
• Submandibular glands: Located beneath the mandible.
  • Produce a mixed secretion of serous and mucous fluids.
  • Wharton's duct opens into the floor of the mouth.
• Sublingual glands: Smallest salivary glands located beneath the tongue.
  • Primarily produce mucous fluid.
  • Multiple small ducts open into the floor of the mouth.

Minor Salivary Glands

• Scattered throughout the oral mucosa (the lining of the mouth).
• Contribute to the overall saliva production.
• Variations in cell types and secretions depending on location.

Regulation of Salivary Secretion

• Stimulated mainly by the parasympathetic nervous system.
• Also influenced by the sight, smell, or thought of food.
• Sympathetic stimulation causes a decrease in salivation.
• Several chemical stimuli (e.g., taste and texture) also promote salivation.

Clinical Considerations

• Xerostomia: Dry mouth, a common symptom in many conditions including Sjogren's syndrome, and side effects of medications. Significant impact on oral health.
• Salivary gland stones (sialolithiasis): These stones can obstruct the salivary ducts, leading to swelling and pain.
• Inflammation of the glands (sialadenitis): Can be caused by bacterial or viral infections.
• Tumors: Both benign and malignant tumors can develop in salivary glands.
• Diagnostic imaging: Salivary gland disorders can be diagnosed using ultrasound, sialography, and computed tomography (CT) scans.

Histology

• Acini: Clusters of secretory cells that produce saliva.
• Ducts: Network of channels that carry saliva to the oral cavity.
• Serous cells: Produce thin, watery secretion rich in enzymes.
• Mucous cells: Produce thick, viscous mucus.

This quiz explores the anatomy and functions of salivary glands. It covers their role in digestion, lubrication, and oral health, including their components and the protective functions of saliva. Test your knowledge about the major salivary glands and how they contribute to our overall well-being.