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The two parotid glands are major salivary glands wrapped around the mandibular ramus in humans. [6] These are largest of the salivary glands, secreting saliva to facilitate mastication and swallowing, and amylase to begin the digestion of starches. [7] It is the serous type of gland which secretes alpha-amylase (also known as ptyalin). [8]
Hypersalivation can contribute to drooling if there is an inability to keep the mouth closed or difficulty in swallowing (dysphagia) the excess saliva, which can lead to excessive spitting. Hypersalivation also often precedes emesis (vomiting), where it accompanies nausea (a feeling of needing to vomit).
Saliva on a baby's lips. Saliva (commonly referred to as spit or drool) is an extracellular fluid produced and secreted by salivary glands in the mouth.In humans, saliva is around 99% water, plus electrolytes, mucus, white blood cells, epithelial cells (from which DNA can be extracted), enzymes (such as lipase and amylase), and antimicrobial agents (such as secretory IgA, and lysozymes).
The serous cell predominates in the parotid, making the gland secrete a mainly serous secretory product. [10] 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.
Blockage, whether caused by salivary duct stones or external compression, may cause pain and swelling of the parotid gland . Koplik's spots which are pathognomonic of measles are found near the opening of the parotid duct. The parotid duct may be cannulated by inserting a tube through the internal orifice in the mouth. [2]
In summary, salivary glands are classified as heterocrine glands because they have a dual role in both exocrine and endocrine functions. They primarily secrete saliva into the oral cavity for digestion, but they can also release specific hormones into the bloodstream with broader physiological effects.
The paired submandibular glands (historically known as submaxillary glands) are major salivary glands located beneath the floor of the mouth.In adult humans, they each weigh about 15 grams and contribute some 60–67% of unstimulated saliva secretion; on stimulation their contribution decreases in proportion as parotid gland secretion rises to 50%. [1]
Preganglionic fibers en route to the pterygopalatine ganglion (destined to ultimately innervate the lacrimal gland and the mucosal glands of the nose, palate, and pharynx) subsequently form the greater petrosal nerve, whereas those en route to the submandibular ganglion (destined to ultimately innervate the submandibular and sublingual salivary glands) subsequently form the chorda tympani.