Which system provides a defense against infection and disease?

Which system provides a defense against infection and disease?

• A. Nervous system
• B. Lymphatic system
• C. Endocrine system
• D. Digestive system

Answer: (B)

The ability to defend against infection relies on the immune system, with the lymphatic system playing a central role. Lymphatic vessels carry immune cells and interstitial fluid, creating a network that supports surveillance and response. Lymphoid organs—lymph nodes, the spleen, thymus, and bone marrow—generate, mature, and organize immune cells such as B cells and T cells. Lymph nodes act as checkpoints where pathogens are trapped and shown to lymphocytes, triggering a targeted response. The spleen filters the blood and helps mount defenses against blood-borne infections. Together, these components produce, train, and deploy the cells and antibodies needed to recognize and destroy pathogens, providing strong defense against disease. Other systems can influence or support immunity in various ways, but they aren’t the primary defense. The nervous system coordinates responses; the endocrine system can modulate immune activity with hormones; and the digestive system contributes barriers and gut immunity. Still, the lymphatic system is the main player in defending the body against infection.

The ability to defend against infection relies on the immune system, with the lymphatic system playing a central role. Lymphatic vessels carry immune cells and interstitial fluid, creating a network that supports surveillance and response. Lymphoid organs—lymph nodes, the spleen, thymus, and bone marrow—generate, mature, and organize immune cells such as B cells and T cells. Lymph nodes act as checkpoints where pathogens are trapped and shown to lymphocytes, triggering a targeted response. The spleen filters the blood and helps mount defenses against blood-borne infections. Together, these components produce, train, and deploy the cells and antibodies needed to recognize and destroy pathogens, providing strong defense against disease.

Other systems can influence or support immunity in various ways, but they aren’t the primary defense. The nervous system coordinates responses; the endocrine system can modulate immune activity with hormones; and the digestive system contributes barriers and gut immunity. Still, the lymphatic system is the main player in defending the body against infection.