Which system is primarily responsible for immune response and fluid balance?

The lymphatic system is primarily responsible for immune response and fluid balance within the body. It plays a critical role in maintaining homeostasis by managing the fluid levels in the body’s tissues. The lymphatic vessels collect excess interstitial fluid (the fluid that surrounds cells) and return it to the bloodstream, preventing fluid accumulation and swelling.

In terms of immune response, the lymphatic system produces and transports lymph, a fluid rich in white blood cells, particularly lymphocytes, which are essential for the body’s defense against infections and diseases. Lymph nodes, key components of the lymphatic system, filter lymph and house immune cells that can recognize and respond to pathogens.

Other systems mentioned do not fulfill this dual role. The nervous system primarily manages communication and control over physiological functions through neural signals, while the endocrine system regulates various functions via hormones. The circulatory system focuses on the transport of blood, nutrients, and gases, but is not involved in the specific immune functions and fluid balance that the lymphatic system handles.