Salivary Glands medium

Salivary Glands Anatomy

• Parotid Gland
  • Largest salivary gland
  • Produces serous saliva (watery, thin, digestive enzymes)
  • Located anterior to the ear, between the masseter muscle and the skin
  • Stensen's Duct
    • Carries saliva from the parotid gland
    • Opens into the oral cavity opposite the 2nd upper molar tooth
  • Innervation
    • Glossopharyngeal nerve (autonomic) - controls saliva production rate
    • Auriculotemporal nerve (sensory)

Submandibular Gland

• Second largest salivary gland
• Produces mixed saliva (mucous and serous)
• Located between the body of the mandible and the mylohyoid muscle
• Contributes 60-65% of total saliva volume
• Wharton's Duct
  • 5 cm long
  • Opens under the anterior part of the tongue, lateral to the lingual frenum, at the sublingual caruncle
• Innervation
  • Chorda tympani nerve (branch of the facial nerve) - carries parasympathetic fibers to the submandibular gland and tongue
  • Lingual branch of the inferior dental nerve - also provides some innervation

Sublingual Gland

• Smallest of the major salivary glands
• Produces predominantly mucous saliva (thick viscous)
• Located on the floor of the mouth in the sublingual fossa
• Contributes 5-10% of total saliva volume
• Bartholin's Duct
  • Main duct
  • 10-20 smaller ducts (Rivinus ducts) also open along the sublingual fold
• Innervation is the same as the submandibular gland

Tubarial Glands

• Recently discovered salivary gland located in the nasopharynx
• May play a role in nasopharyngeal/oropharyngeal lubrication and swallowing
• May be involved in Sjögren's Syndrome

Minor Salivary Glands

• Numerous small groups of secretory units found throughout the oral cavity, except for the gingiva
• Mixed saliva, mostly mucous, with lots of salivary proteins
• Contribute over 10% of total saliva volume
• Named based on location (e.g., buccal or labial glands)

Salivary Gland Structure

• Epithelium - lines the ducts and produces saliva
• Connective Tissue
  • Surrounds the epithelium, providing support and protection
  • Divided into the capsule (outer layer) and septa (inner divisions)
  • Contains the nerve and blood supply to the gland

Adenomeres

• Working part of a salivary gland
• Surrounded by connective tissue

Acini

• Secretory units within adenomeres
• Made up of secretory cells
• Resting against the surrounding connective tissue
• Types:
  • Mucous Acini - produce mucous saliva which binds food into a bolus and protects the oral cavity
  • Serous Acini - produce serous saliva, which lubricates food, initiates enzyme-based digestion, removes debris, and dilutes food
  • Serous-Mucous Acini - serous cells form a demilune around mucous cells

Myoepithelial Cells

• Embrace the acini secretory cells
• Contract and squeeze to force saliva out of the lumen and into the ducts

Acinar Fluid

• Not yet saliva
• Consists of:
  • Water
  • Inorganic ions
  • Small molecules and products synthesized by cells (mucoproteins and amylase)
• Modified as it travels through the ducts

Ducts

• Saliva travels and undergoes further modification through these
• Three types:
  • Intercalated Ducts - lined by a single layer of cuboidal epithelial cells
  • Striated Ducts - bulk of the duct system, contribute to saliva modification
  • Excretory Ducts - open into the oral cavity

Salivary Stimulants

• Food and other stimuli (e.g., taste, smell, chewing)
• Parasympathetic nerve stimulation (increases saliva production)
• Sympathetic nerve stimulation (decreases saliva production)

Salivary Gland Disorders

Xerostomia (Dry Mouth)

• Can be caused by:
  • Emotional disturbances (e.g., anxiety)
  • Mouth breathing
  • Smoking
  • Medications (e.g., antidepressants, antianxiety drugs)
  • Talking for long periods

Degenerative

• Sjögren's Syndrome
  • Immunological disorder causing dry eyes and dry mouth
  • Acini are destroyed
  • Commonly associated with rheumatoid arthritis and Raynaud's phenomenon

Inflammation/Infection

• Mumps
  • Acute viral infection causing inflammation and swelling of the parotid glands
• Nicotine Stomatitis
  • Inflammation of minor salivary glands on the palate due to heat from tobacco use
  • Causes red dots on the palate

Sialosis

• Painless swelling of the parotid glands, not caused by inflammation or infection
• May occur on its own or due to other medical conditions (e.g., bulimia, diabetes, pregnancy, obesity, kidney failure)

Neoplasms (Tumours)

• Benign
  • Warthin's tumor
  • Pleomorphic adenoma
• Malignant
  • Salivary gland carcinoma
  • Acinic cell carcinoma

Functional Disorders

• Dry mouth caused by:
  • Emotional disturbances e.g., anxiety, depression, stress
  • Mouth breathing
  • Smoking
  • Drugs
  • Talking for long periods

Test your knowledge on the anatomy and functions of the salivary glands, focusing on the parotid and submandibular glands. This quiz will cover their locations, ducts, saliva production types, and innervation. Perfect for students of anatomy and physiology.