What are the types of animal tissues?
Based on the four major functions carried out in the animal body, namely, protection, connection, movement and locomotion, and signal transmission, tissues are divided into four major types: Epithelial, Connective, Muscular and Nervous.
Types of animal tissues
What is Epithelial tissue?
Epithelial tissue lies above the entire body, forming a protective covering. It also forms a barrier between the various organs separating them.
The epithelial tissue structure is quite evident from the function it performs, that is protection. It has tightly packed cells, forming continuous sheets. The tissue lacks intercellular spaces and has a minimal amount of cementing material. Every single substance that passes in or out of the cells must cross the epithelial layer at least once. Accordingly, the permeability of cells will differ in various epithelia depending upon the exchange of materials.
Epithelial tissue
What is the Basement membrane?
The epithelial cells rest on a thin, fibrous, supportive membrane-like structure known as the basement membrane. The basement membrane helps to hold the cells together in a single, straight line to form a uniform and consistent layer.
Basement membrane
What are the types of epithelial tissues?
The epithelial cells on the basement membrane are modified based on the function they perform.
- Filtration: For this, the structure needs to be a very flat surface. This type of epithelium is referred to as simple Squamous
- Absorption and secretion: For this, a larger surface area is required. So the cells here are tall, pillar-like to form the Columnar
- Strength: Along with a larger surface area, strength and support are also needed. For this, the basement layer has cube-like cells that form the Cuboidal
- Secretions: Certain organs need specialized secretions. For this, a few cells are modified to perform secretion of specific chemicals, like hormones or enzymes. These cells are called the Gland cells, and the epithelium consisting of such cells is called the Glandular
Types of epithelial tissue