Physiology of Salivary Glands

Study Notes

Oral Stimuli and Salivary Glands

Oral stimuli include gustatory, masticatory, olfactory, thermoreceptive, and nociceptive stimuli.
Afferent pathway involves transmission of stimuli to the nucleus of the solitary tract (NST), thoracic spinal cord, and finally to salivary nuclei, medulla, and brainstem.

Mechanisms of Salivary Secretion

Parasympathetic nerves evoke most fluid secretion, some protein secretion, cause vasodilation, and contract myoepithelial cells.
Sympathetic nerves act collaboratively with parasympathetic nerves, seldom cause fluid secretion, cause protein secretion, and contract myoepithelial cells.
Denervation of parasympathetic nerves causes gland atrophy, while denervation of sympathetic nerves causes some gland atrophy.

Formation and Secretion of Saliva

Saliva is formed by acinar cells in the salivary gland epithelial cells.
Acinar cells synthesize and secrete different mixtures of proteins in different glands:
- Parotid gland: serous
- Submandibular gland: seromucous
- Sublingual gland: mucous
Salivary protein secretion includes blood proteins (albumin, IgA) and acinar proteins (amylase, mucins, PRPs, statherins).

Ductal Cell Modification of Saliva

Striated ductal cells modify saliva by reabsorbing sodium and secreting potassium.
Resting/unstimulated saliva is isotonic, while stimulated saliva is hypotonic.
Ductal cell modification of saliva involves changes in sodium, potassium, and chloride concentrations.

Salivary Glands

Salivary glands are exocrine glands that secrete onto the surfaces of the mouth.
There are major salivary glands (parotid, submandibular, sublingual) and minor salivary glands (present in most oral mucosal surfaces).
Minor salivary glands are present in the oral mucosa, including labial and palatine minor glands.

Newly Discovered Paired Salivary Glands

Newly discovered paired salivary glands are present in the oral cavity.
Salivary secretion is a nerve-mediated reflex involving collaboration between parasympathetic and sympathetic nerves.

Description

This quiz covers the structure and function of salivary glands, including major and minor salivary glands, their ductal system, and the importance of saliva. Test your knowledge of the physiology of salivary glands and their role in the mouth.