Anatomy and Physiology II Practice Test

Lymph primarily moves toward the heart, which is an essential characteristic of the lymphatic system. This one-directional flow helps facilitate the return of excess interstitial fluid to the bloodstream and plays a crucial role in immune function by moving lymph, which contains lymphocytes and other immune cells, toward lymph nodes for filtration and activation.

The lymphatic vessels, equipped with valves, ensure that the flow is unidirectional, preventing backflow. As skeletal muscles contract and during movements, lymph is propelled through these vessels, ultimately returning to the circulatory system via the thoracic duct or the right lymphatic duct, depending on the body region.

Other options do not accurately represent the dynamics of lymph flow. The lymphatic system does not allow movement away from the heart, nor does it function bi-directionally or remain stagnant, as stagnant fluid would lead to edema and impaired immune response.