carotid artery and their function is mainly vasoconstriction. Preganglionic parasympathetic fibers leave the brain stem from inferior salivatory nucleus in the glossopharyngeal nerve and then through its tympanic and then the lesser petrosal branch pass into the otic ganglion. There, they synapse with postganglionic fibers which reach the gland by hitch-hiking via the auriculotemporal nerve, a branch of the mandibular nerve. It is important to note that the terminal branches of the facial nerve arise in the parotid plexus from within the parotid gland. These nerves then merely pass through the parotid gland and do not innervate the gland itself. Histology The gland has a capsule of its own of dense connective tissue but is also provided with a false capsule by the investing layer of the deep cervical fascia. The fascia at the imaginary line between the angle of the mandible and the mastoid process splits into a superficial and a deep lamina to enclose the gland. The risorius is a small muscle embedded with this capsule substance. The gland has short, striated ducts and long, intercalated ducts. The intercalated ducts are also numerous and lined with cuboidal epithelial cells and have lumina larger than those of the acini. The striated ducts are also numerous and consist of simple columnar epithelium, having striations that represent the infolded basal cell membranes and mitochondria. Though the parotid gland is the largest, it provides only 25% of the total salivary volume. The serous cell predominates in the parotid, making the gland secrete a mainly serous secretory product. The parotid gland also secretes salivary alpha-amylase (sAA), which is the first step in the decomposition of starches during mastication. It is the main exocrine gland to secrete this. It breaks down amylose (straight chain starch) and amylopectin (branched starch) by hydrolyzing alpha 1,4 bonds. Additionally, the alpha amylase has been suggested to prevent bacterial attachment to oral surfaces and to enable bacterial clearance from the mouth. Development The parotid salivary glands appear early in the sixth week of the prenatal development and are the first major salivary glands formed. The epithelial buds of these glands are located on the inner part of the cheek, near the labial commissures of the primitive mouth (from ectodermal lining near angles of the stomodeum in the 1st/2nd pharyngeal arches; the stomodeum itself is created from the rupturing of the oropharyngeal membrane at about 26 days.) These buds grow