Salivary glands

The parotid gland is found overlying the ramus of the mandible
Anterior and inferior to the external ear
The gland occupies the parotid fascial space
The gland extends from the zygomatic arch to the angle of the mandible.
The facial nerve and its branches pass through the parotid gland
The external carotid artery also passes through the gland
It gives off its two terminal branches, the maxillary artery and the superficial temporal artery within the gland.
Posteriorly, it is related to the posterior belly of the digastric, the stylohyoid, and the sternocleidomastoid.
The gland has four surfaces superior, superficial, anteromedial and posteromedial
The surfaces are separated by three borders, anterior, posterior and medial
The parotid duct (Stenson's duct) empties into the buccal cavity opposite the upper second molar
The parotid papilla mark's the opening of the duct

Although the facial nerve runs through this gland, it does not supply its parasympathetic innervation
Secretion of saliva by the parotid gland is controlled by postsynaptic parasympathetic fibres originating in the inferior salivatory nucleus
These leave the brain via the tympanic nerve branch of glossopharyngeal nerve, travel through the tympanic plexus (located in the middle ear), and then form the lesser petrosal nerve until reaching the otic ganglion
After synapsing in the Otic ganglion, the postganglionic fibres travel as part of the auriculotemporal nerve to reach the parotid gland
Sympathetic nerves originating from superior cervical ganglion and giving rise to the external carotid nerve plexus reach the gland by travelling along the external carotid arterial branches
Parasympathetic stimulation produces a water rich, serous saliva
Sympathetic stimulation leads to the production of a low volume, enzyme-rich saliva
There is no inhibitory nerve supply to the gland

Lies superior to the digastric muscles
Each submandibular gland is divided into superficial and deep lobes
Separated by the mylohyoid muscle
The superficial portion is larger and the mylohyoid muscle runs below it
The deep portion is smaller
Secretions are delivered into Wharton's ducts on the superficial portion
It hooks around the posterior edge of the mylohyoid muscle
The ducts are then crossed by the lingual nerve drain into the sublingual caruncles on either side of the lingual frenulum
This occurs along with the major sublingual duct

Parasympathetic innervation to the submandibular glands is provided by the superior salivatory nucleus via the chorda tympani, a branch of the facial nerve that synapses in the submandibular ganglion
After this it follows the lingual nerve leaving this nerve as it approaches the gland
Increased parasympathetic activity promotes the secretion of saliva
The sympathetic nervous system regulates submandibular secretions through vasoconstriction of the arteries that supply it.
Increased sympathetic activity reduces glandular blood flow and decreases salivary secretions, producing an enzyme rich serous saliva.