Where are continuous capillaries typically found?

• A. Kidneys
• B. Muscle and brain
• C. Glomeruli
• D. Intestinal villi

Answer: (B)

Continuous capillaries have an uninterrupted endothelial lining with tight junctions and a continuous basement membrane, which allows them to control what passes between blood and tissue. This makes them ideal for tissues that require strict barrier function and regulated exchange, like the brain, where the blood-brain barrier relies on these tight junctions to limit paracellular leakage, and skeletal muscle, where steady, controlled delivery of oxygen and nutrients with minimal unwanted protein leakage is important.

In contrast, the kidneys use fenestrated capillaries in the glomeruli to permit filtration of plasma, and the intestinal villi are supplied by fenestrated capillaries to maximize absorption. These structures rely on more permeable vessels, so they’re not continuous.

So continuous capillaries are typically found in muscle and brain.