Anatomy & Physiology The salivary glands are divided into 3 major groups, and many minor salivary glands. The 3 major groups are paired salivary glands (i.e. we have 2 parotid, 2 submandibular, and 2 sublingual salivary glands). All salivary glands play a major role in digestion, mastication, and protection.
The autonomic nervous system controls the salivary secretions so the salivary glands receive both sympathetic and parasympathetic fibers; the quantity and composition of saliva will vary depending on the stimulating fibers (i.e. parasympathetic or sympathetic). Generally speaking, the Facial nerve supplies the oral cavity with parasympathetic fibers, while the trigeminal nerve distributes the sympathetic fibers to the oral cavity but they originate from T1 (Thoracic spinal nerves).
Parotid Gland: The parotid gland is the largest salivary glands; we have 2 glands one on each side of the face in the preauricular area. The parotid gland is covered by the parotid sheath (dense fibrous capsule that invest the parotid gland and it is continuous with the cervical fascia).
Stensen’s duct is the duct that emerges from the anterior boarder of the gland It moves superficial to the masseter muscle and pierce the buccinators muscle and oral mucosa to and opens into the oral cavity buccal mucosa in the area facing the upper 1st and 2nd molars.
The parotid glands also contain the parotid lymph nodes chain, which drain lymphatics from the parotid gland and the surrounding area.
The facial nerve separates the gland into two lobes one is superficial (above the facial nerve, while the second is the deep lobe below the facial nerve). That is why surgical operation, trauma, or tumors may affect the facial animation.