Glandular Epithelium

What Is Glandular Epithelium?

The glandular epithelium is the kind of epithelial tissue specialised in the formation of glands responsible for producing and secreting different substances, from enzymes and hormones to mucus and sweat. It takes part in the following way to maintain homeostasis through the control and secretion of vital biochemical compounds required in a myriad of bodily functions.

Glandular epithelium helps in digestion by the secretion of enzymes, and performs metabolic functions by the production of hormones; it protects the mucosal surfaces through the production of mucus and participates in thermoregulation through sweating.

Structure Of Glandular Epithelium

The structure of Glandular cells is described below-

General Morphology Of Glandular Cells:

Glandular cells are specialised to perform secretion. They contain a lot of rough endoplasmic reticulum and Golgi apparatus devoted to the synthesis and packaging of secretory products. Their shape ranges from columnar to cuboidal.

Types

Glandular epithelium into unicellular glands, an example is goblet cells and multicellular, an example - salivary glands. They are further divided based on their morphology and functions.

Classification Of Glands

The classification of Glandular cells is described below-

Based On The Secretion Method

• Merocrine Glands: The product is secreted through exocytosis, without any loss of cellular material, for instance, salivary and pancreas.

• Apocrine Glands: The product is secreted by shedding portions of their cytoplasm, such as mammary glands.

• Holocrine Glands: Entire cells disintegrate to secrete their products. Examples include sebaceous glands.

Based On The secretion type

• Serous Glands: These glands produce watery enzyme-rich secretions. Examples include the parotid glands.

• Mucous Glands: These are glands that produce viscous, mucus-rich secretions. Examples are the goblet cells in the intestine.

• Mixed Glands: They produce both serous and mucous secretions. Examples are submandibular glands.

Based On Duct structure

• Simple glands: These have a single unbranched duct. Examples include sweat glands.

• Compound glands: Have branched ducts. Examples include the pancreas

Types Of Glandular Epithelium

The types of Glandular cells are described below-

Exocrine Glands

Exocrine glands are glands with ducts through which they convey their secretions out to the epithelial surface. They are located with either a single duct or and simple compound with a branched duct.

Examples: Salivary glands, and sweat glands.

Endocrine Glands

Endocrine glands are ductless, and they secrete their hormones directly into the circulatory system. High vascularisation supports the secretion of hormones.

Examples: Thyroid gland, adrenal glands

Functions Of Glandular Epithelium

The functions of Glandular cells are described below-

Hormones Secretion

Many hormones are secreted by the endocrine glands which, in turn, control several physiological activities. For example, thyroxine is secreted by the thyroid gland.

Secretion Of Enzymes

Digestive enzymes are secreted by exocrine glands. The best example is the enzymes from the pancreas, which form a part of the gastrointestinal system and participate in the digestion of food material.

Mucus secretion

Mucous glands produce mucus that lubricates and protects surfaces lining respiratory and digestive tracts.

Other functions

Other functions of glandular epithelium include thermoregulation—sweat glands—and metabolic waste excretion—sebaceous glands.

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