Homeostasis--the key concept to physiological control

Immunity is a response to the invasion of the body by non-self antigens (Figure 8). Immunity is characterised by being: Xenophobic--it distinguishes self from non-self components. Adaptive--it produces a response to an antigenic invasion. Highly specific--its response is personal for different antigenic insults. Anamnestic--its memory component allows the occurrence of primary and secondary responses.