Question: Which of the following is not the first line of defense?
A Skin
B Tears
C Saliva
D Fever
Answer: Fever
| Aspect | First Line of Defense | Second Line of Defense |
| Function | Provides immediate, non-specific protection against pathogens and foreign invaders. | Acts as a rapid but non-specific response to infection when the first line is breached, and helps initiate the specific immune response. |
| Components of defense | · Mucus membranes
· Stomach acid · Saliva · Microbiome |
· Neutrophils
· macrophages · Natural killer cells · Complement proteins · Inflammatory response |
| Specificity | Non-specific | Specific |
| Response Time | Immediate | Rapid |
| Effector Mechanisms | Barriers and processes that prevent pathogens from entering the body or from causing harm. | Phagocytosis (engulfing and destroying pathogens), inflammation, and activation of the complement system. |
| Adaptive Immunity | Not part of the adaptive immune response, which is the third line of defense in the body. | Initiates and coordinates the adaptive immune response when necessary. |