EPITHELIAL TISSUE Epithelial tissue covers body surfaces and lines body cavities, hollow organs and ducts of glands. Epithelial cells are tightly packed together and there is little space between the cells. Since epithelium is found on free surfaces it must be attached to the underlying tissues. This attachment is accomplished at the basement membrane. The basement membrane is a thin extracellular layer consisting of two layers; the basal lamina and the reticular lamina. The side of the epithelial tissue that faces the basement membrane is the basal surface. The side of the epithelial tissue that faces the body cavity, lumen or environment is the apical surface.
Bio 223 Lab 1 Page 9 CSN Biology Dept Simple Squamous Epithelium Simple squamous epithelium is comprised of a single layer of thin, flat cells. This tissue allows for a large amount of transport including filtration, diffusion, secretion and osmosis. Some epithelial tissues are given special names based upon their location. The simple squamous epithelium that lines body cavities is referred to as a mesotheliumand the layer that lines the heart and blood vessels is called an endothelium.(Atlas Fig 3.3, Text table 4.2a) Body Locations: Lining of heart and blood vessels Alveoli Glomerular capsule Lining body cavities Slides: Kidney Lung (alveoli) Simple squamous epithelium Drawn at _______ magnification
Bio 223 Lab 1 Page 10 CSN Biology Dept Stratified Squamous Epithelium Stratified squamous epithelium is comprised of multiple layers of cells that are squamous at the apical surface. It is found in areas of the body that are exposed to mechanical stresses. (Atlas Fig 3.6, Text table 4.3a) Body Locations Epidermis Lining of the Rectum Lining of the Anus Lining of the Vagina Lining of the Esophagus Slides: Skin (fingertip) Simple Cuboidal Epithelium Simple cuboidal epithelium is a single layer of cuboidal cells. This tissue is found where secretion and absorption occur and provides limited protection. (Atlas Fig 3.4, Text Table 4.2b) Body Locations Kidney tubules Thyroid Gland Slides: Kidney Stratified squamous epithelium Drawn at _______ magnification Simple cuboidal epithelium Drawn at _______ magnification
Bio 223 Lab 1 Page 11 CSN Biology Dept Simple Columnar Epithelium Simple columnar epithelium is a single layer of cells that are taller than they are wide and is located where secretion and absorption occur. The cells may have