1. Epithelial Tissue Activity

2. Simple Squamous Description –Single layer of thin, flattened cells that fit tightly together. Function –Allows diffusion and filtration (ex: oxygen and carbon dioxide are exchanged) Location –Lines the air sacs (alveoli) of the lungs –Forms walls of capillaries –Line the blood and lymph vessels –Covers membranes that line body cavities.

3. Simple Cuboidal Description –Single layer of cubed-shaped cells. Function –Secretion and reabsorption in the kidneys –secretion from glands. Location –Lines the follicles of the thyroid gland –Covers the ovaries –Lines the kidney’s tubules –lines the ducts of certain glands (salivary, pancreas, and liver).

4. Simple Columnar Description –Single layer of elongated cells. Function –Ciliated and helps move an egg through the uterine tube. –Non-ciliated protects underlying tissues, secretes digestive fluids, and absorbs nutrients from digested food. Location –Ciliated is found in the uterine tube. –Non-ciliated lines the uterus and portions of the digestive track (stomach and the intestines).

5. Pseudostratified Description – Single layer of cells where the columns are at different heights. Function – Sticky and trap dust and microorganisms. Cilia move mucus and captured particles out of airways. Location –Lines the passageways of the respiratory system.

6. Stratified Squamous Description –Many layers of flattened cells. Function –Prevents water and other substances from escaping underlying tissues and blocks chemicals and microorganisms from entering. Location –Outermost layer of skin. –Lines oral cavity, esophagus, vagina, and anal cavity.

7. Transitional Description –Many layers of cubed-shaped and elongated cells. Function –Forms a barrier that helps prevent the contents of the urinary tract from diffusing back into the internal environment. Location –Inner lining of the urinary bladder, lines ureters, and part of the urethra.