1. Squamous Epithelium: Cells are thin and flat, like scales. They are found in areas where diffusion or filtration is important, such as the lining of blood vessels (endothelium), the lining of body cavities (mesothelium), and the alveoli of the lungs.
2. Cuboidal Epithelium: Cells are cube-shaped with a central nucleus. They are found in areas involved in secretion and absorption, such as the lining of kidney tubules, salivary glands, and the thyroid gland.
3. Columnar Epithelium: Cells are tall and column-shaped, often with nuclei located near the base. They are found in areas involved in absorption and secretion, such as the lining of the stomach, intestines, and the uterus.
It's important to note that within these three categories, there are further subtypes based on the arrangement of cells (e.g., simple vs. stratified) and the presence of specialized structures (e.g., cilia).
