Immune system
Immune system is the biological defense system of the body that protects against infections, diseases, harmful microorganisms, and foreign substances. It consists of specialized cells, tissues, organs, and proteins that work together to identify and destroy pathogens such as bacteria, viruses, fungi, and parasites. :contentReference[oaicite:0]{index=0}
The immune system also helps remove damaged cells and contributes to healing and tissue repair. :contentReference[oaicite:1]{index=1}
Overview
The immune system protects the body through coordinated immune responses.
The immune response process can be represented as:
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The immune system distinguishes between the body’s own cells and foreign substances known as antigens. :contentReference[oaicite:3]{index=3}
Components of the Immune System
Major components of the immune system include:
- White blood cells
- Antibodies
- Lymph nodes
- Bone marrow
- Spleen
- Thymus
- Tonsils
- Lymphatic vessels
These structures work together to defend the body from infection. :contentReference[oaicite:4]{index=4}
Types of Immunity
Innate Immunity
Innate immunity is the body's first line of defense and responds rapidly to harmful substances.
It includes:
- Skin barriers
- Mucous membranes
- Macrophages
- Neutrophils
- Natural killer cells
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Innate immunity acts quickly but does not provide long-term immune memory. :contentReference[oaicite:6]{index=6}
Adaptive Immunity
Adaptive immunity develops after exposure to pathogens and provides specific immune responses.
Main immune cells include:
- B cells
- T cells
Adaptive immunity can remember pathogens and respond more effectively during future infections. :contentReference[oaicite:7]{index=7}
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White Blood Cells
White blood cells, also called leukocytes, play major roles in immune defense.
Important types include:
- Lymphocytes
- Macrophages
- Neutrophils
- Eosinophils
- Basophils
These cells identify, attack, and destroy pathogens. :contentReference[oaicite:9]{index=9}
Antibodies
Antibodies are proteins produced by B cells that recognize and neutralize harmful antigens.
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Each antibody is specific to a particular antigen. :contentReference[oaicite:11]{index=11}
Functions
Major functions of the immune system include:
- Fighting infections
- Destroying pathogens
- Removing damaged cells
- Supporting wound healing
- Providing immune memory
- Preventing disease spread
The immune system also helps protect against abnormal cell growth such as cancer. :contentReference[oaicite:12]{index=12}
Immune System Disorders
Immune system disorders include:
- Autoimmune diseases
- Allergies
- Immunodeficiency disorders
- Chronic inflammation
Examples include asthma, lupus, rheumatoid arthritis, and HIV/AIDS. :contentReference[oaicite:13]{index=13}
Vaccination
Vaccines help train the immune system to recognize and fight pathogens.
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Vaccination plays an important role in disease prevention and public health. :contentReference[oaicite:15]{index=15}
Importance
The immune system is essential for survival because it protects the body from harmful microorganisms and diseases while maintaining internal biological balance. :contentReference[oaicite:16]{index=16}