Final answer:
Squamous epithelial cells with a count of less than 5 per high power field in a sample are generally considered normal. These cells are flat with a centrally located nucleus and are part of tissue layers that protect or line body surfaces.
Step-by-step explanation:
Squamous epithelial cells are a type of cell that cover surfaces and line cavities in the body, often serving as a barrier or a form of protection. In the context of health, a 'normal' cell count usually refers to a microscopic evaluation, such as in urine or sputum samples. The term 'normal' is relative and can vary based on the specific test and part of the body being examined. Generally, a count of less than 5 squamous epithelial cells per high power field (HPF) in urine is considered normal. These cells are characterized by being flat and thin with a centrally located nucleus and may be found in simple or stratified layers, as seen in tissues such as the lungs for gas exchange, or on the skin and lining of the mouth for protection. A nucleus of a squamous epithelial cell is approximately 10 µm in size, which is useful for comparison with other cells, like bacteria, in a sample.
Squamous epithelial cells can be considered normal even if their count is less than 5. The count of these cells is usually seen in a microscope field. If the count is less than 5, it is still considered normal because squamous epithelial cells are typically found in different parts of the body, such as the skin, mouth, and vagina, where they form a protective lining or covering.