Salivary glands: serous and mucous acini !
- Organ
Three pairs of glands make saliva: one makes watery saliva, one mixed, and one thick mucus; their ducts adjust the salt before it reaches the mouth.
Updated 2026-11-01
See it in 3D: Parotid gland · Submandibular gland · Sublingual gland
What it is
Salivary glands are branched glands made of secretory end pieces (acini) and a duct tree. Serous cells make watery, enzyme-rich saliva; mucous cells make pale, mucus-filled cells. The parotid is serous, the submandibular is mixed with mostly serous cells, and the sublingual is mixed with mostly mucous cells. Striated ducts reabsorb sodium and make saliva hypotonic. Stones, mumps and tumours of these glands are common exam topics.
Structure
- Serous acini: pyramidal cells with round basal nuclei and basophilic cytoplasm with zymogen granules.
- Mucous acini: pale, foamy cells with flattened nuclei pushed to the base.
- Serous demilunes: crescents of serous cells capping mucous acini in mixed glands.
- Myoepithelial cells around acini and intercalated ducts squeeze secretion out.
- Ducts: intercalated (low cuboidal), striated (columnar with basal striations from infolded membranes and mitochondria), then excretory ducts.
Function
- Saliva moistens food, starts starch digestion with amylase and protects teeth.
- Striated ducts reabsorb sodium and chloride and secrete potassium, so final saliva is hypotonic.
- IgA from plasma cells around the acini is transported into saliva.
The three major salivary glands
| Gland | Acini | Duct | Clinical |
|---|---|---|---|
| Parotid | Serous; fat cells increase with age | Parotid (Stensen) duct, opposite the upper second molar | Most salivary tumours; mumps; facial nerve passes through it |
| Submandibular | Mixed, mostly serous | Submandibular (Wharton) duct, floor of the mouth | Most salivary stones |
| Sublingual | Mixed, mostly mucous | Many small ducts on the floor of the mouth | Ranula (mucus retention) |
Clinical notes
- Pleomorphic adenoma: the most common salivary tumour, usually in the parotid, mixing epithelial and chondromyxoid tissue.
- Warthin tumour: parotid, linked to smoking, with oncocytic epithelium over lymphoid stroma.
- Submandibular stones are more common because its saliva is thicker and its duct runs upward.
- Sjögren syndrome: lymphocytes infiltrate and destroy salivary and lacrimal glands.
Test yourself
Think of the answer, then tap the question to see it.
Which major salivary gland is purely serous in adults?
The parotid gland.
Why is final saliva hypotonic?
Striated ducts reabsorb sodium and chloride with little water, and secrete potassium.
In which gland do most salivary stones form?
The submandibular gland, because its saliva is more viscous and its duct runs upward against gravity.
What are serous demilunes?
Crescent-shaped caps of serous cells on mucous acini, seen in mixed glands such as the submandibular and sublingual.
See it in 3D
The structures of Durgical's 3D anatomy where it is found.
Related
- Oral cavity, tongue and teeth
- Pancreas: acini and islets
- Glands: exocrine vs endocrine, secretion types
Related conditions
Microorganisms
Educational content on normal microscopic structure and its clinical relevance; no substitute for studying slides or for a health professional's advice.
Sources: 23.3 The Mouth, Pharynx, and Esophagus - Anatomy and Physiology 2e | OpenStax (OpenStax (Rice University), 2022); Accessory Organs | SEER Training (National Cancer Institute (SEER Training), 2026).
Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake
Representative model, for educational purposes only.