Salivary Glands

How many submucosal glands make up minor salivary glands in the oral cavity?

600–1000

How much saliva is released daily?

~1.5L of which 90% of the total saliva comes from the major glands while the remaining 10% is secreted by the minor SGs.

Histologically, what is the parenchyma of each gland comprised of?

1. Secretory end-pieces (acini)
2. Ducts

What is the basic functional unit of the gland?

The basic functional unit of the gland is the acinus, which are either SEROUS or MUCOUS, and consists of secretory cells that produce saliva.

Mucous acini with a few attached serous acinar cells “serous demilune” are also found, particularly in submandibular and sublin- gual glands.

Describe the excretory ducts of the major salivary glands.

The parotid and submandibular glands have single excretory ducts opening into the oral cavity called Stenson’s and Wharton’s ducts, respectively, whereas the sublingual gland invariably possesses multiple tiny ducts (ducts of Rivinus) that open directly into the sublingual fold.

In some individuals, abnormal development of ducts of Rivinus leads to a single duct (Bartholin duct) opening anteriorly.

What does a salivary gland comprise of?

A salivary gland comprises a course of branched ducts that end in a tubular or spherical secretory unit or acinus.

A bunch of grapes is probably the best analogy that simulates salivary gland histology the stem representing ducts and grapes resembling secre- tory endpieces. The opening of the excretory duct in the oral cavity branches off into smaller interlobar and interlobular excretory ducts.

Major SGs are wrapped by a thick fibrous capsule that extends into the gland dividing it into large segments “lobes” and smaller parts (lobules).

The thick fibrous tissue partition (septa) divides the gland into multiple lobes and is continuous with the capsule, which encom- passes the blood vessels and nerves supplying the gland.

The fine connective tissue partitions sur- round the ducts and endpieces within the lobules.

The parotid gland is the first gland to develop a capsule and remains the last to com- plete encapsulation. The sublingual gland has a poorly developed capsule.

What is the ECM of salivary glands made of?

The extracellular matrix is made of collagen and elastic fibers along with glycoproteins and proteoglycan.

What are the main cellular components of salivary glands?

Fibroblasts and other inflammatory cells constitute the main cellular components.

What is the smallest functioning unit present in a salivary gland?

The secretory cell is the smallest functioning unit present in a gland.

What are the 2 main types of secretory cells in salivary glands and how do they varyx`?

2 main types of secretory cells exist in salivary glands; serous and mucous cells. These cells vary in basic microscopic structure and types of molecular secretions.

What are the main differences between serous and mucous secretory cells?

Serous cells primarily contain glycoproteins, which have many enzymatic activities, whereas mucous cells contain mucin glycoproteins, which are different in structure from serous cell glycoproteins. Mucins mainly lubricate the oral soft tissues and act as a barrier against microbial aggregation on mucosal surfaces.

Serous cells produce enzymes, while mucous cells secrete mucins for lubrication.