Immune system

• Lymphocytes are white blood cells involved in the immune response.
• Antigens are molecules that trigger an immune response.
• The immune response is the body's reaction to foreign substances, such as bacteria or viruses.
• B lymphocytes produce antibodies that bind to antigens on pathogens, marking them for destruction by phagocytic cells.
• T lymphocytes directly attack infected host cells or release chemicals called cytokines that stimulate other immune responses.
• The innate immune system is non-specific, while the adaptive immune system is specific to antigenic determinants on pathogens.
• Antibody-mediated immunity involves B lymphocytes producing specific antibodies against foreign substances (antigens) such as bacteria, viruses, and parasites.
• Innate immunity includes physical barriers such as skin and mucous membranes, chemical defenses like stomach acid, and cellular responses including phagocytosis by macrophages and neutrophils.
• B lymphocytes produce antibodies specific to antigens.
• T lymphocytes kill infected host cells directly or activate other immune cells.
• Macrophages engulf pathogens and present them on their surface for recognition by T lymphocytes.
• T lymphocytes directly attack infected host cells through cytotoxicity.
• Phagocytosis involves engulfment and digestion of pathogens by specialized cells called macrophages.
• Adaptive immunity involves lymphocytes (B and T) producing antibodies or directly attacking infected cells through cytotoxic T cells.
• Complement proteins enhance the activity of other components of the immune system.
• T lymphocyte and B lymphocyte move around in the lymphatic system and blood, most commonly found in the lymph nodes
• The lymphatic system is responsible for the transportation of Antigen presenting cells to Lymph nodes for antigen recognition and the production of leukocytes. Additionally, while both B and T cells are produced in the Bone marrow, B cells mature in the Bone marrow and T cells mature in the Thymus.
• Primary lymphatic tissues: Bone marrow and thymus
• Secondary lymphoid tissues: Lymph nodes, spleen and tonsils
• Inflammation is a reaction that causes heat, redness, swelling and pain. This happens when white blood cells called mast cells release a chemical called histamine.