How the Body Defends Itself from Disease

The human body has a number of defence measures in place to prevent diseases. These make up the immune system.
The main components of the immune system are the skin, mucous membranes, immune cells, and the chemicals these cells produce.
The skin acts as a physical barrier, preventing pathogens from entering the body. It’s the body’s first line of defence.
Mucous membranes, such as those in the nose and lungs, trap pathogens to prevent further infection.
In addition to acting as physical barriers, both the skin and mucous membranes secrete antimicrobial substances that kill pathogens.
When pathogens manage to breach these barriers, they meet the body’s second line of defence, the immune cells.
White blood cells (leucocytes) detect and eliminate pathogens. There are several types of white blood cells each with a specific role.
Phagocytes engulf and digest pathogens. They can also call for back-up, releasing signals that attract more immune cells.
Lymphocytes produce antibodies that target specific pathogens. Each antibody is specific to one type of pathogen.
If the body is infected with the same pathogen in the future, the immune system produces the specific antibodies much faster, this is known as immunity.
Inflammation is another key response of the immune system to pathogens. It draws immune cells to the area and helps isolate the infection.
Vaccination introduces a harmless form of a pathogen into the body. This stimulates production of antibodies and ‘memorises’ the pathogen, providing immunity.
Antibiotics are medicines that help fight bacterial infections. They work by killing bacteria or inhibiting their growth.
However, overuse of antibiotics can lead to antibiotic resistance, where bacteria evolve to survive the drugs.
It’s important to understand that while the immune system is effective, it can sometimes malfunction. This can result in allergies, autoimmune diseases, and immunodeficiency disorders.
Living a healthy lifestyle, including regular exercise, a balanced diet, and getting enough sleep, can assist in maintaining a robust immune system.
If the immune system is severely compromised, due to conditions such as HIV/AIDS or as a side effect of medical treatment, additional precautions may be necessary to prevent infection.
Adequate vaccinations, frequent hand washing, and avoiding close contact with individuals who have infectious diseases are effective preventative measures.