Which clear fluid carries lymphocytes in the body's tissue spaces?

Lymph is the clear fluid that plays a crucial role in the immune system by transporting lymphocytes, which are a type of white blood cell essential for immune responses. This fluid circulates through the lymphatic system, allowing for the movement of lymphocytes from the tissue spaces into the lymph nodes, where they can respond to pathogens or other foreign substances.

Lymph is distinct from other bodily fluids because it specifically contains lymphocytes and plays a direct role in the maintenance of fluid balance, as well as in the body's immune function. Unlike serum, which is the fluid part of blood that remains after blood clots, or interstitial fluid, which is the fluid that fills the spaces between cells before it enters the lymphatic system, lymph is specifically designed for the transportation of immune cells. Plasma, on the other hand, refers to the liquid component of blood that contains a variety of substances, including electrolytes, proteins, and hormones, but it is not focused on the immune function like lymph is.