Question

Describe various types of epithelial tissues with the help of labeled diagrams.

Answer 1

Hint: Epithelial tissue consists of variously shaped cells closely arranged in one or more layers that cover or line the external and internal surfaces of various body parts. The number of layers and type of cells varies in different parts of the body.

Complete step by step answer:
Epithelial tissue was introduced by Rush. These cells consist of a basal surface and a free surface. There are two types of epithelial tissues, Simple and Compound tissues. -Simple Epithelial: It consists of a single layer of cells resting on the basement membrane. It lines the body cavity, ducts, and tubes. Based on structural modifications, simple epithelial is further divided as Squamous, Cuboidal, Columnar, Ciliated, PseudoStratified, Glandular.
Squamous Epithelium: It is composed of a single layer of thin flattened cells hanging irregular boundaries. They are found to be having polygonal shapes. The nuclei of cells are flat and sometimes lie in the middle of cells.

Cuboidal Epithelium: It consists of a single layer of cube-like cells lying on a basement membrane. The nuclei are round and lie in the center.

Columnar Epithelium: It consists of a single layer of tall and slender cells, lying on a basement membrane. The nuclei are elongated along the long axis of the cells and lie near the base of the cell.

Ciliated Epithelium: If the columnar or cuboidal cells bear cilia on their free surface, they are called ciliated epithelial.

Pseudostratified Epithelium:  it's a kind of epithelium that comprises only one layer of cells but has its cell nuclei positioned during a manner implicational stratified epithelium.

Glandular Epithelium: Some of the cells of the Epithelium get specialized for secretion and are called the glandular epithelium.

Compound Epithelium: It consists of more than one layer of cells. These cells protect underlying tissues.

Note: In ovaries and seminiferous tubules of the testis, the cuboidal epithelium is called germinal epithelium because it produces gametes. In cuboidal epithelium, when free surface bears microvilli. It is known as a brush bordered cuboidal epithelium. There are goblet cells present in the columnar epithelium to produce mucus. The intestinal juice constitutes the secretion of mucosa from the brush border along with the goblet cell secretion.