**Glands in our body are formed by Epithelial Tissue**

**Introduction:**
Glands are specialized organs or tissues in the body that produce and secrete substances for various functions. These substances can include hormones, enzymes, oils, sweat, and saliva. Glands are formed by epithelial tissue, which is a type of tissue found throughout the body that lines the external and internal surfaces of organs and structures.

**Explanation:**
Epithelial tissue is composed of closely packed cells with very little extracellular matrix between them. It is responsible for forming the linings and coverings of organs, as well as the glands that produce and secrete substances. Epithelial tissue can be classified into two main types: glandular epithelium and surface epithelium.

1. **Glandular Epithelium:**
Glandular epithelium is specialized for secretion and is responsible for forming glands in the body. It is made up of cells that are capable of producing and releasing substances. Glandular epithelium can be further classified into two types: exocrine glands and endocrine glands.

- **Exocrine Glands:** Exocrine glands secrete their substances onto the surface of an organ or tissue, either directly or through ducts. Examples of exocrine glands include sweat glands, salivary glands, and sebaceous glands. These glands are composed of epithelial cells that secrete substances into ducts, which then transport the substances to the surface of the organ or tissue.

- **Endocrine Glands:** Endocrine glands secrete their substances directly into the bloodstream. These substances, called hormones, are then transported to target organs or tissues where they exert their effects. Examples of endocrine glands include the thyroid gland, adrenal glands, and pituitary gland. Endocrine glands are also composed of epithelial cells that secrete substances, but unlike exocrine glands, they lack ducts.

2. **Surface Epithelium:**
Surface epithelium forms the linings and coverings of organs and structures. It is responsible for protecting underlying tissues, regulating the exchange of substances, and providing sensory information. Surface epithelium can be further classified based on the number of cell layers (simple or stratified) and the shape of the cells (squamous, cuboidal, or columnar). Examples of surface epithelium include the lining of the respiratory tract, digestive tract, and blood vessels.

**Conclusion:**
In conclusion, glands in our body are formed by epithelial tissue, which is responsible for producing and secreting substances. Glandular epithelium specifically forms exocrine and endocrine glands, while surface epithelium forms the linings and coverings of organs and structures.

An organised collection of secretory epithelial cells. Most glands are formed during development by proliferation of epithelial cells so that they project into the underlying connective tissue.