Cuboidal Epithelium – Types Diagram, and Functions

The Cuboidal Epithelium is one of the types of epithelial tissue. The specific feature of this tissue is that all the cells are cuboid in shape. The main functions of epithelial tissue are protection, secretion, and absorption. The cuboidal epithelium is found in the linings of the ovaries, kidneys, salivary glands, and other large glands. The cuboidal epithelium is divided into various types according to its number of layers and structure.

In this article, we will study what cuboidal epithelium is, the types and locations of cuboidal epithelium, simple cuboidal epithelium, stratified cuboidal epithelium, and the specialized variants and functions of cuboidal epithelium.

What is a Cuboidal Epithelium?

The cuboidal epithelium is a type of epithelium that consists of cube-shaped cells with nearly equal dimensions in height and width, giving them a uniform appearance under a microscope. These cells are usually found lining the surfaces of ducts, glands, and other structures where absorption, secretion, protection, and filtration play essential roles that are important for maintaining health and proper body functioning.

Types and Location of Cuboidal Epithelium

Cuboidal cells are named so because they are shaped like cubes. These are found in the lining of the ovaries, pancreas, kidneys, and salivary glands. The cuboidal epithelium is further divided into two types according to the number of layers it possesses. These are simple cubic epithelium and stratified cubic epitheliums. Let us understand these in detail.

Simple Cuboidal Epithelium

This simple type consists of a single layer of cube-like cells that are as tall as they are wide. The nucleus is usually spherical, giving the cells a uniform appearance, and all the cells are directly attached to the basement membrane. They are usually found in places that are secretory and absorptive. The large cube shape provides the proper surface area for these activities.

Examples of Simple Cuboidal Epithelium

The following are examples of where simple cuboidal epithelium is found:

• Kidney Tubules: In the kidneys, simple cuboidal epithelium is essential for the absorption and secretion processes in the renal tubules. These cells help in blood filtration and purify the blood, playing an important role in urine formation.
• Glands and Ducts: This epithelium lines the surfaces of the ducts of many glands like the salivary, thyroid, and pancreas, and it is involved in the production of various substances. For example, the thyroid gland is involved in the production of thyroid hormones. It’s also found on the surface of the ovaries, where it’s involved in the formation of egg cells.

Stratified Cuboidal Epithelium

The stratified cuboidal epithelium consists of two or more layers of cells and is involved in protection. It is found in larger ducts of glands like sweat glands, mammary glands, and salivary glands. This multilayer structure helps in the protection of the underlying tissues. The cells underlying this tissue are ciliated and columnar. The cells of stratified cuboidal epithelium are all connected to each other with the help of special proteins. This epithelium is present in a lesser amount in the human body as compared to a simple cuboidal epithelium.

Examples of Stratified Cuboidal Epithelium

The following are examples of where stratified cuboidal epithelium is found:

• Sweat Glands: In sweat glands, the stratified cuboidal epithelium participates in the production of sweat and provides protection against wear and tear.
• Mammary Glands: It also lines the larger ducts of mammary glands, and stratified cuboidal epithelium plays an important role in the production of milk and provides structural strength.
• Salivary Glands: The larger ducts of salivary glands are lined with stratified cuboidal epithelium, helping in the transportation of saliva.

Specialized Variants

Beyond the standard simple cuboidal epithelium and stratified cuboidal epithelium types, this displays specialized variants that perform specific roles. These specialized forms show modifications that enable them to effectively carry out their specific functions. Here are some of the key specialized variants of cuboidal epithelium:

1. Ciliated Cuboidal Epithelium – This type consists of cube-shaped cells and hair-like structures equipped with cilia on their surface. Ciliated cuboidal epithelium can be found in such regions where the movement of particles over the cell surface is necessary. For example, it might be present in certain parts of the fallopian tubes, where the cilia help to move mucus.
2. Secretory Cuboidal Epithelium – This secretory cuboidal epithelium variant is specific for secretion and contains a large number of mitochondria and it is found in glandular tissues. It is commonly found in various glands like salivary glands, sweat glands and it is responsible for producing and releasing hormones or sweat.

Functions of Cuboidal Epithelium

Following are the functions of cuboidal epithelium:

• The major functions of the cuboidal epithelium, particularly in glandular tissue, is secretion. These cells are found in the glands of the body, thyroid gland, pancreas, and salivary glands. They are involved in producing and releasing substances like hormones and saliva.
• The simple cuboidal epithelium plays a major role in absorption in the kidney tubules. Here, the simple cuboidal epithelium absorbs substances from the urine, for controlling body fluid composition and maintaining electrolyte balance.
• The stratified variant of the cuboidal epithelium provides protection against mechanical and chemical stress in the larger duct of glands.
• Cuboidal epithelium cells lining the ducts of glands provide a path for the movement of glandular secretions.
• In some organs, these cuboidal epithelium cells provide structural support.

FAQs – Cuboidal Epithelium

How does Cuboidal Epithelium help in Excretion?

Cuboidal epithelium cells specially found in renal tubules of kidney helps in elimination of waste by reabsorption of water and maintaining osmotic balance.

Where is Cuboidal Epithelium Found in the Human Body?

The primary locations of cuboidal epithelium within the human body are kidney tubules, glands and ducts, ovaries, mammary glands, sweat glands, and salivary glands.

Why is Cuboidal Epithelium in Cube Shape?

Cuboidal epithelial cells have a cube shape because they are specialised in secretion & absorption in places that require a substantial amount of secretion or absorption.

Why is Cuboidal Epithelium called Germinal Epithelium?

Cuboidal epithelium is known as germinal epithelium as it surrounds the ovary and the inside walls of the male testes’ seminiferous tubules.

What are the Effects of Dysfunctional Cuboidal Epithelium in Human Health?

Dysfunctional Cuboidal epithelium can lead to various health issues like in the kidneys, damage to the cuboidal cells of the tubules can result in impaired kidney function.