– The immune system is the body's defense mechanism against harmful substances, such as bacteria, viruses, fungi, and parasites.
– The immune system consists of various cells, tissues, organs, and proteins that work together to recognize and eliminate foreign invaders.
– The immune system also helps the body to remember previous infections and prevent them from happening again.
– The immune system can be divided into two main parts: the innate immune system and the adaptive immune system.
1) The innate immune system is the first line of defense and responds quickly to any foreign substance.
2) The innate immune system includes physical barriers, such as the skin and mucous membranes; chemical barriers, such as saliva and stomach acid; and cellular barriers, such as white blood cells that can engulf and destroy pathogens.
– The innate immune system also produces inflammatory signals that attract more immune cells and activate the adaptive immune system.
– The adaptive immune system is the second line of defense and responds more slowly but more specifically to foreign substances. The adaptive immune system involves two types of white blood cells: B cells and T cells.
B cells produce antibodies, which are proteins that bind to specific antigens (parts of foreign substances) and mark them for destruction.
T cells recognize antigens presented by other cells and either kill them directly or activate other immune cells.
– The adaptive immune system also develops memory, which means that it can remember the antigens it has encountered before and respond faster and stronger the next time.
The immune system is essential for maintaining health and preventing diseases.
– However, sometimes the immune system can malfunction or become impaired due to various factors, such as genetic disorders, infections, aging, stress, or medications.
Some examples of immune system disorders are:
🔅 Autoimmune diseases
– These are conditions where the immune system mistakenly attacks the body's own cells and tissues, causing inflammation and damage. Some examples are type 1 diabetes, rheumatoid arthritis, lupus, multiple sclerosis, and celiac disease.
🔅 Allergies
– These are hypersensitive reactions where the immune system overreacts to harmless substances, such as pollen, dust, food, or animal dander. This can cause symptoms such as sneezing, itching, rash, swelling, or anaphylaxis (a life-threatening reaction that affects breathing and blood pressure).
🔅 Immunodeficiencies
– These are conditions where the immune system is weakened or absent due to genetic defects or acquired factors, such as HIV infection, cancer treatment, or organ transplantation. This can make the body more susceptible to infections and cancers.
