How chemical defence mechanisms in the body reduce chance of infection?
The body has several chemical defence mechanisms that help reduce the chance of infection:
1. Skin and Mucous Membranes: The skin acts as a physical barrier against pathogens, while mucous membranes in the respiratory, digestive, and urinary tracts produce mucus that traps and expels microorganisms.
2. Stomach Acid: The acidic environment in the stomach (pH of about 1-2) helps kill many ingested microorganisms.
3. Enzymes: Various enzymes, such as lysozyme in tears and saliva, have antimicrobial properties. Lysozyme breaks down the cell walls of certain bacteria.
4. Interferons: These proteins are produced in response to viral infections and help protect uninfected cells by inhibiting viral replication.
5. Complement System: A group of proteins that work together to destroy invading microorganisms. Complement proteins can directly lyse microbial cells or enhance phagocytosis by opsonizing them, making them more recognizable to phagocytic cells.
6. Antimicrobial Peptides: These small peptides have direct antimicrobial effects against bacteria, fungi, and viruses. They can disrupt microbial membranes or interfere with their metabolism.
7. Antibodies: Produced by B cells, antibodies bind to specific antigens on the surface of pathogens, neutralizing them and marking them for destruction by other immune cells.
8. Phagocytes: Specialized immune cells, such as macrophages and neutrophils, engulf and destroy microorganisms through a process called phagocytosis.
9. Natural Killer (NK) Cells: These cells can recognize and kill virus-infected cells or cancerous cells without prior sensitization.
10. Fever: An elevated body temperature during a fever can inhibit the growth of some microorganisms and enhance the immune response.
11. Cytokines and Chemokines: These chemical messengers help coordinate the immune response and attract immune cells to the site of infection.
12. Gut Microbiota: The beneficial bacteria residing in the gut produce antimicrobial substances that can inhibit the growth of harmful microorganisms.
These chemical defence mechanisms work together to provide a multilayered defence against pathogens, reducing the chance of infection and helping to maintain overall health. However, it's important to note that these mechanisms may be compromised by factors such as immune deficiencies, aging, chronic diseases, or certain medications. In these cases, individuals may be more susceptible to infections.