Epithelial Tissue PDF

What is Epithelial Tissue? Epithelial Tissue is a type of tissue that covers the surfaces of our body, both inside and out. It forms the outer layer of our skin, lines our internal organs, blood vessels, and body cavities, and also makes up our glands. This tissue acts as a barrier, protecting our...

What is Epithelial Tissue? Epithelial Tissue is a type of tissue that covers the surfaces of our body, both inside and out. It forms the outer layer of our skin, lines our internal organs, blood vessels, and body cavities, and also makes up our glands. This tissue acts as a barrier, protecting our body from physical damage, pathogens, and dehydration. Function of Epithelial Tissue Protection -Skin protects from sunlight & bacteria & physical damage. Absorption -Lining of small intestine, absorbing nutrients into blood. Filtration -Lining of Kidney tubules filtering wastes from blood plasma. Secretion -Different glands produce perspiration, oil, digestive enzymes and mucus. Types of Epithelial Tissue 1.Simple Squamous Epithelium Structure: Single layer of flat, thin cells. Function: Allows for easy diffusion Location: - Lining of blood vessels (endothelium). - Alveoli of lungs. - Glomerular capsules in the kidneys. - Serous membranes (e.g., peritoneum, pleura). 2. Simple Cuboidal Epithelium Structure: Single layer of cube-shaped cells. Function: Secreation and absorption. Location: - Kidney tubules. - Glands and their ducts (e.g., thyroid gland). - Surface of the ovaries. 3.Simple Columnar Epithelium Structure: Single layer of tall, column-like cells; often has microvilli or cilia. Function: Absorpion and secreation of mucus and enzymes. Location: - Lining of the stomach, intestines, and gallbladder. - Uterine tubes (ciliated). - Small bronchi (ciliated). 4.Stratified Squamous Epithelium Structure: -Multiple layers of cells, with the top layer flat and thin; can be keratinized or non-keratinized. Function:Provides protection against abrasion and infection. Location: - Skin (keratinized). - Lining of the mouth, esophagus, and vagina (non-keratinized). 5.Stratified Cuboidal Epithelium Structure: -Multiple layers of cube-shaped cells. Function: Protection and secreation. Location: - Ducts of sweat glands. - Mammary glands. - Salivary glands. 6.Stratified Columnar Epithelium Structure: -Multiple layers of cells, with the top layer being columnar. Function: Protection and secreation Location: -Part of the male urethra. -Large ducts of some glands. 7. Pseudostratified Columnar Epithelium Structure: Single layer of cells of varying heights, giving the appearance of multiple layers; often ciliated. Function: Secreation, particularly of mucus; ciliated types help move mucus. Location: - Lining of the trachea and upper respiratory tract (ciliated). - Ducts of large glands (non-ciliated). - Male urethra (non-ciliated). 8.Transitional Epithelium Structure: -Multiple layers of cells that can change shape from squamous to cuboidal, allowing stretching. Function: Allows for stretching and expansion. Location: - Lining of the urinary bladder. - Ureters. - Part of the urethra..