What is the main function of epithelial cells found in urine?

Epithelial cells in urine primarily serve the function of protecting underlying tissues. These cells line various surfaces and cavities within the body, acting as a barrier against pathogens and physical damage. In the context of the urinary system, epithelial cells are important for maintaining the integrity of the urinary tract, aiding in the protection from potential irritants or infections that could arise from the urine itself. Their presence in urine can indicate the shedding of these protective cells, which may occur due to irritation or injury to the urinary epithelium.

Other options, such as transporting nutrients and producing hormones, relate more closely to different types of epithelial tissues found in areas such as the gastrointestinal tract or endocrine glands. Filtering waste products is a key function of the kidneys, specifically involving nephron structures like glomeruli and tubules, rather than being a function of epithelial cells themselves transitioning into urine. Thus, the role of epithelial cells in providing protection makes this choice the most accurate regarding their purpose in urine.