How does the filtration membrane prevent certain substances from entering the filtrate?

The filtration layer keeps certain substances from entering the filtrate as a result of counteracts substantial substances, for example, proteins and cells from leaving the blood utilizing the fenestrations, storm cellar film, and podocytes.

If a person could not digest food anymore, what would probably happen to that person? ... The person would gain weight because the undigested food would sit in the person's body. The person would not lose or gain weight, but it would take longer for the body to use the food that was eaten.