GB2: Immune System

• Immune System - is composed of special cells, proteins, tissues, organs that protect the body from the potential dangers of foreign bodies, thus keeping the body healthy and free from infections.
• Immune Response - the collective and coordinated process performed by immune system upon the introduction of a foreign substance
• Adaptive Immunity - Active Immunity and Passive Immunity
• Active immunity - Natural and vaccination
• Passive Immunity - Maternal and Artificial
• Physical and Physiological Barriers - skin, mucous membranes, cilia, body temperature, pH
• Innate Immunity - defends the body in a nonspecific or stereotypic manner. It is not long-lasting immunity. Involves physical and chemical barriers (skin, mucus, saliva, etc. ), the process of inflammation proteins, and specialized immune cells.
• First Line of Defense - it consists of surface barriers and internal structures. The skin, accounting for 15 percent of your body weight and its dead skin layers, provides a nearly impenetrable barrier that helps against the entry of microorganisms. Good bacteria that symbiotically live on the skin digest skin oil, then produce acids that act as a barrier.
• Infection - successful invasion of pathogens (physical and physiological barriers)
• Second Line Defense - if the first line of defense is penetrated, the second line of defense is activated. The body will mount a cellular counterattack using certain cells and chemicals to kill invaders, but it is still nonspecific. It produces WBC. Lymphatic system that collects and recycles fluids that leaked from the circulatory system.
• Lymphocytes - engulf and multiply
• WBC - Macrophages, Neutrophils, Natural Killer Cells, Dendritic, Eosinophils, Basophils, Mast Cells,
• Macrophages - patrol and ingest microorganisms through phagocytosis.
• Neutrophils - Most abundant circulating WBCs similar to macrophages. Engulf bacteria through phagocytosis.
• Natural Killer Cells - Killing the cell by puncturing a hole.
• Dendritic Cells - Alerts the adaptive immune system, when an antigen is present. They act as messengers between the innate and adaptive immunity.
• Eosinophils - Granular WBCs with enzymes that target parasitic worms
• Basophils - Contains histamines which cause inflammation during immune responses and allergic responses.
• Mast Cells - Response to injury or allergic reaction together with basophils.
• Lymphocytes - Responsible for specific immunities/injuries.
• Antimicrobial Proteins - Proteins that kill or inhibit the growth of microorganisms
• Antigen - a foreign substance, such as toxins or the body part of a pathogen that can trigger immune response
• Cytokines - Chemical messengers that are released by cells and travel through the bloodstream
• Third Line of Defense - it is also known as a specific immune response or adaptive immune response. It takes days or even weeks to becomes established.
• B cells - mature in the bone marrow
• T cells - cells mature in thymus glands
• antibodies - these are specialized proteins that circulate in blood plasma and lymph
• Neutralization - antibodies prevent a virus or toxic protein from binding their target
• Opsonization - a pathogen tagged by antibodies is consumed by a macrophage or neutrophil.
• Complement Activation - antibodies attached to the surface of a pathogen cell activate the complement system
• Humoral Immunity - an adaptive immunity that mediates by antibodies produced by B lymphocytes.
• Cell Mediated Immunity - An adaptive immunity that mediates by cytotoxic lymphocytes and TH cells without involvment of antibodies