Question

Describe the structure, position and function of different types of epithelial tissue.

Answer 1

Different types of epithelial tissues:

Squamous epithelial tissue:
Structure:

• These tissues are composed of a single layer of thin and flat plate-like cells.
• These have uninucleated cells present at the center of the cell.
• The cells fit closely like the bricks in a wall to form a smooth membrane.

Position/location

• It is found in the outer layer of the skin and covers the cavities and ducts, also found in the lining of the mouth, tongue, and oesophagus.

Function:

• Its functions include protecting the internal organ and allowing diffusion to take place easily in blood and alveoli.

Cuboidal epithelium tissue:
Structure:

• This is composed of cubelike cells that fit closely, look like squares but the free surface appears hexagonal.
• These cells are uninucleated and the nucleus placed centrally.

Location:

• This tissue lines the inside of the kidney tubules and the salivary gland.

Function:

• The function of this tissue is secretion and absorption, also providing support.

Columnar epithelial tissue:
Structure:

• Columnar epithelium tissue is composed of a single layer of column-like cells.
• The nucleus is single and placed at the bases of cells.
• A conspicuous striated border of microvilli at the free surface end of each cell increases surface area for absorption and secretion.

Location:

• These are found in the inner lining layer of the stomach and intestine.

Function:

• It helps in protection, absorption and secretion.

Ciliated epithelium tissue:
Structure:

• These tissues have the columnar cells rectangular in shape.
• The cells are uninucleated placed at the middle of the cell.
• Columnar epithelium develops protoplasmic outgrowth called cilia; this epithelium is called ciliated epithelium.

Location:

• Ciliated epithelium is present in the trachea, bronchi of the lungs, the uterus and oviduct.

Function:

• It helps in the movement of mucus, urine, eggs, sperms and cerebrospinal fluid in a particular direction.