Question 9

The major function of the lymphatic system is the return of interstitial fluid to the blood.

The lymphatic system plays a crucial role in maintaining fluid balance in the body by returning interstitial fluid, which has leaked out of the blood vessels, back to the bloodstream.

A) return of formed elements to the blood

This option is incorrect as the lymphatic system does not primarily function to return formed elements, such as red and white blood cells and platelets, to the blood. Rather, it is responsible for transporting lymph, which contains interstitial fluid and immune cells, rather than the blood's formed components.

B) production of interstitial fluid

This choice is incorrect because interstitial fluid is produced as a result of the filtration of blood plasma through the capillaries into the surrounding tissues, not by the lymphatic system itself. The lymphatic system primarily collects and returns this fluid to the bloodstream.

C) return of interstitial fluid to the blood

This option is correct as the lymphatic system collects excess interstitial fluid from tissues and eventually returns it to the circulatory system, thus playing a vital role in fluid homeostasis.

D) production of clotting factors

This option is incorrect because the lymphatic system does not produce clotting factors; these are primarily synthesized by the liver. Clotting factors are proteins necessary for blood coagulation, and their production is unrelated to the lymphatic system's functions.

Conclusion

The correct answer, "return of interstitial fluid to the blood," accurately reflects a key function of the lymphatic system, which is essential for maintaining fluid balance in the body. All other options either mischaracterize the role of the lymphatic system or address functions that are not associated with it, thereby confirming that C is the only appropriate choice.