Video Transcript
Here is a diagram of the urinary
system with some parts labeled. Which part carries blood containing
harmful nitrogenous wastes to the kidneys?
To answer the question, we need to
consider the parts of the urinary system and their functions. Let’s start by naming the labeled
parts of this urinary system diagram. Label one is the renal artery. Label two is the renal vein. Label three is pointing to one of
the two kidneys. Label four is pointing to one of
the two ureters. And label five is pointing to the
bladder.
Now let’s think about the path of
the blood through the urinary system so that we can determine which part carries
blood with harmful nitrogenous waste to the kidneys. First, blood from the body travels
through the renal arteries. Second, the renal arteries deliver
blood to the kidneys. Third, the blood from the kidneys
is carried back to the heart by the renal veins. So we can see that the blood never
goes into either the ureters or the bladder. The ureter’s function is to carry
the waste filtered by the kidneys to the bladder, which then excretes the waste in
the form of urine from the body. So we can rule out both the ureters
and the bladder.
Now let’s consider the function of
the kidneys. The kidneys’ role is to filter out
harmful nitrogenous waste from the blood. So whichever blood vessel delivers
blood to the kidneys must be carrying harmful nitrogenous waste. And whichever takes blood away must
be carrying clean, filtered blood. So let’s see which of the two blood
vessels labeled in the diagram is doing each of these jobs.
The renal arteries are delivering
blood to the kidneys, and the renal veins are taking blood away. Therefore, we can rule out the
renal veins because they are taking blood away. They must, therefore, be carrying
clean, filtered blood away from the kidney and back to the heart. This leaves the renal arteries,
which deliver blood to the kidneys. The renal arteries carry blood
containing harmful nitrogenous waste to the kidneys so that the kidneys can filter
out the waste.
So the correct answer is label
one. The renal arteries carry blood
containing nitrogenous wastes to the kidneys.
