Final answer:
The immune system protects the body from harmful invaders like pathogens and tumor cells through a complex network of defenses, including the innate and adaptive immune systems. Immune surveillance is particularly important for eliminating tumor cells while immune memory aids in faster response to previously encountered pathogens. Stress can impact the immune system's efficiency.
Step-by-step explanation:
What is the Immune System?
The immune system is a complex network of cells, tissues, and organs that work together to protect the body from pathogens, which are agents that cause disease, as well as other foreign invaders such as tumor cells. It comprises two subsystems: the innate immune system and the adaptive immune system. The innate immune system provides immediate, non-specific defense through barriers like skin and mucus and responses such as inflammation. The adaptive immune system, on the other hand, offers a specialized and lasting defense, with immune cells like T cells and B cells targeting specific pathogens and tumor cells by recognizing unique proteins called antigens.
Immune Surveillance and Tumor Cells
An important aspect of the immune system is immune surveillance, particularly the identification and destruction of tumor cells by killer T cells, which can recognize the abnormal antigens these cells present. This function is crucial for preventing the spread of cancer within the body.
Lymphatic System and Immune Memor
As part of the body's third line of defense, the adaptive immune system's lymphatic network remembers previous encounters with pathogens, allowing for a quicker and stronger response upon re-exposure. This memory is fundamental in fighting off repeated infections from the same pathogen.
Stress and the Immune System
Stress can influence the immune system, potentially affecting its ability to fend off infections and diseases. It's important for the immune system to be functional so that it can maintain health by eliminating harmful agents.
Overall Function of the Immune System
The main responsibility of the immune system is to protect the body against a wide range of threats, including pathogens and tumor cells. It achieves this through a series of defenses, much like a medieval castle's layers of security from moat to inner soldiers.