Salivary Secretion

Salivary secretion is unique in that it is regulated almost exclusively by the nervous system. Saliva is produced by a heterogeneous group of exocrine glands called the salivary glands. Saliva performs several functions. It facilitates chewing and swallowing by lubricating food, carries im-munoglobulins that combat pathogens, and assists in carbohydrate digestion.

The parotid, submandibular (submaxillary), and sublingual glands are the major salivary glands. They are drained by individual ducts into the mouth. The sublingual gland also has numerous small ducts that open into the floor of the mouth. The secretions of the major glands differ significantly. The parotid glands secrete saliva that is rich in water and electrolytes, whereas the submandibular and sublingual glands secrete saliva that is rich in mucin. There are also minor salivary glands located in the labial, palatine, buccal, lingual, and sublingual mucosae.

The salivary glands are endowed with a rich blood supply and are innervated by both the parasympathetic and sympathetic divisions of the autonomic nervous system. Although hormones may modify the composition of saliva, their physiological role is questionable, and it is generally believed that salivary secretion is mainly under autonomic control.

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Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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