The biological distinction between 'self' and 'non-self' in your immune system
In short: Your body is constantly engaged in a sophisticated surveillance operation to distinguish your own cells from invading pathogens. This video breaks down the non-specific defenses that act as your first line of protection against bacteria, viruses, and fungi.
The body employs non-specific defenses to block pathogens before they can cause systemic infection. These include physical barriers like the skin and mucous membranes, as well as chemical defenses such as lysozymes. When these are breached, the body utilizes expulsive reflexes like coughing or the inflammatory response—characterized by vasodilation and swelling—to neutralize threats.
A critical component of this system is the recognition of antigens. The immune system must differentiate between 'self' antigens and 'non-self' antigens. The video also explores antigenic variability, a mechanism that allows pathogens to change their appearance and potentially evade the body's established immunity.
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Sources
- Summary by Intellect · source: A-Level Biology - Defence Mechanisms - Pathogens | Non-specific Defences | Antigens (2027/28 exams)
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