A 38-year-old patient

presents with a painful swelling of the submandibular gland on the left side.

Especially during meals, the gland is painful and produces a large amount of

saliva. During this, small stones are released from the duct. The cause of his

difficulties is the so-called sialolithiasis, i. e. the formation of salivary

stones. The most common cause is a change in the composition of saliva. The

viscosity of saliva increases, and a mucoprotein matrix is ​​formed, into which

inorganic material (calcium, magnesium, phosphorus salts) is subsequently

deposited and a stone is formed. Which parts of the submandibular gland are

involved in the production and composition of saliva?