Emergency Medical Technician (EMT) Intermediate Practice Exam

Proteins of the immune system that recognize foreign substances are called?

1. Antibodies

2. Antigens

3. Enzymes

4. Hormones

The correct answer is: Antibodies

Antibodies are proteins produced by the immune system in response to foreign substances known as antigens. When a pathogen, such as a virus or bacterium, enters the body, the immune system identifies it as a threat. The antibodies specifically bind to these antigens, creating an immune response that helps neutralize or eliminate the invading pathogens. This process is crucial for protecting the body against infections and plays a key role in the immune system's ability to remember past infections for faster responses in the future. Antigens, while closely related to antibodies, refer to the foreign substances themselves that induce an immune response. Enzymes are biological catalysts that speed up chemical reactions in the body and do not have a primary role in identifying foreign substances. Hormones are regulatory messengers in the body that coordinate various physiological processes, but they are not involved in the immune response in the same way that antibodies are. Understanding the distinction between these terms is essential in immunology and helps clarify the roles they play in the body's defense mechanisms.