a. Which anatomical characteristic ensures that the flow of lymph through a lymph node is slow? b. Why is this desirable?

Video transcript

Welcome back, everyone. Let's look at our next question, which of the following factors facilitates the flow of lymph through lymphatic vessels. A blood pressure, B, contraction of the heart, c contraction of the skeletal muscles or D oxygen diffusion. Well, it's pretty easy to eliminate right away choice. A blood pressure since that has to do with the flow of blood and lymph moves through completely different vessels and choice d oxygen diffusion since lymph doesn't carry oxygen. So let's look at our remaining two choices. Contraction of the heart or contraction of the skeletal muscles. Well, what facilitates the flow of lymph is choice c contraction of the skeletal muscles, contraction of the heart, as we recall is what pushes the flow of blood around the body. But in the case of lymphatic vessels, they're not part of the circulatory system and its contraction of the skeletal muscles surrounding the limp vessels. And as these muscles contract and relax, that acts as a pump to keep the lymphatic fluid flowing through the vessels. Again, they have valves to keep it all flowing in one direction. So that squeezing of the skeletal muscles pumps the fluid around. So which facilitates the flow of lymph through the lymphatic vessels, choice c contraction of the skeletal muscles. See you in the next video.