Anatomy Practice Exam

What does interstitial fluid become when it enters lymph capillaries?

1. Blood plasma

2. Cerebrospinal fluid

3. Lymph

4. Serous fluid

The correct answer is: Lymph

When interstitial fluid enters lymph capillaries, it is referred to as lymph. This transformation occurs because lymph capillaries are specialized vessels that collect excess interstitial fluid, which has accumulated in the spaces between cells throughout body tissues. The primary role of lymph capillaries is to ensure that the fluid is returned to the circulatory system while also helping to transport immune cells and waste products. As the interstitial fluid drains into these capillaries, it takes on the name "lymph," reflecting its unique composition and the specific role it plays in the lymphatic system. Lymph consists of water, proteins, lipids, and various immune cells, and it is crucial for maintaining fluid balance in the body and supporting the immune response. Other fluids mentioned, such as blood plasma, cerebrospinal fluid, and serous fluid, serve different functions and do not relate to the process the question addresses. Blood plasma is the liquid component of blood, cerebrospinal fluid cushions the brain and spinal cord, and serous fluid lubricates the surfaces of serous membranes. In contrast, as interstitial fluid enters lymph capillaries, it specifically becomes lymph, which is vital for the lymphatic system's functions.