The tubules of the kidney are composed of__________and the cells of proximal tubules feature Select an answer and submit. For keyboard navigation, use the up/down arrow keys to select an answer. a.stratified epithelia; cilia b.simple epithelia; microvilli c.stratified epithelia; microvilli d.simple epithelia, cilia
The Correct Answer and Explanation is:
The correct answer is b. simple epithelia; microvilli.
Explanation:
The kidneys are composed of a complex network of nephrons, which are the functional units of the kidney. The nephrons consist of different parts, including the glomerulus, proximal tubule, loop of Henle, distal tubule, and collecting duct. The tubules of the kidney, including the proximal tubules, are lined with a specific type of epithelial cells that serve important functions in filtration, absorption, and secretion.
- Simple epithelium refers to a single layer of cells, which is found in various parts of the kidney, including the proximal tubules. This type of epithelium allows for efficient exchange of substances like ions, water, and small molecules between the tubules and the surrounding capillaries.
- Microvilli are microscopic projections found on the surface of cells. In the case of the proximal tubules of the kidney, these structures significantly increase the surface area for absorption. This is crucial because the proximal tubule is involved in reabsorbing a large percentage of filtered substances from the glomerulus, including glucose, amino acids, sodium ions, and water. The microvilli help maximize the area available for these processes to occur efficiently.
In contrast, other options in the question are incorrect for the following reasons:
- a. Stratified epithelia; cilia: Stratified epithelium is composed of multiple layers of cells, which are typically found in areas subject to wear and tear, like the skin or the mouth. The kidney tubules do not feature stratified epithelium, and cilia are not involved in the function of the proximal tubule.
- c. Stratified epithelia; microvilli: Again, stratified epithelium is not found in the proximal tubules, and microvilli are the correct feature, but stratified epithelium is not involved.
- d. Simple epithelia; cilia: While simple epithelium is correct for the proximal tubules, cilia are not the characteristic feature. Cilia are found in other parts of the nephron, such as in the cells of the collecting ducts, but not in the proximal tubules where microvilli are present.
In summary, the proximal tubule cells are lined with simple epithelium and have microvilli to increase surface area for efficient absorption and reabsorption, making option b the correct answer.