What are the different types of Epithelium and Tissues?
Glandular epithelium: A type of simple epithelium, cuboidal and columnar cells specialized in secretion are identified as glandular epithelium.
Based on the layer of cells, the glandular epithelium is further classified into two types. Isolated glandular cells such as goblet cells of the digestive system are unicellular, while a cluster of cells present in salivary glands is multicellular.
A. Unicellular B. Multicellular
Compound Epithelium:
These are multi-layered cells and play an essential role in protecting the organ from mechanical and chemical damage. This type of cell is usually seen in the skin, the inner lining of ducts of pancreatic and salivary glands. These cells are usually held together with little intracellular material which acts as links between two cells. Three types of cell junctions are seen in between the compound epithelium, namely, tight, gap, and adhering junctions.
Tight junctions are responsible to stop the leakage of substances from the cell.
Adhering junction maintains the strength of the neighboring cells by adhering cell walls of the cluster.
Gap junctions enable communication between the cells by connecting the cytoplasm thus, transferring ions, and substances across different cells.
What is Connective Tissue?
Going by the name, connective tissue performs the function of linking and supporting other tissues of the organ and the body. All connective tissues are made up of cells that secrete a protein called collagen or elastin. Collagen provides strength, elasticity, and flexibility to the tissue. Other than collagen, the cells also secrete polysaccharides that act as a ground substance thus keeping the cells and tissues attached in a matrix.
Connective tissues are classified into three types namely, loose connective tissue, dense connective tissue, and specialized connective tissue.
What is Loose Connective Tissue?
Cells and fibers are loosely arranged in a semi-fluid ground substance and are defined as loose connective tissue. It serves as a support framework for multi-layered epithelium and consists of fibroblasts, macrophages, and mast cells. One type of loose connective tissue is adipose tissue. Adipose tissue is located beneath the skin and consists of cells that store fats.
A. Areolar tissue B. Adipose tissue