Immune System Bio12 Final
What are the two main types of immunity?
Innate (nonspecific) and adaptive (specific) immunity.
What is the function of the immune system?
To defend the body against pathogens (bacteria, viruses, fungi, parasites), remove dead or damaged cells, and recognize and eliminate abnormal cells.
What are the first lines of defense in the innate immune system?
Physical barriers (skin, mucous membranes), chemical barriers (stomach acid, lysozymes), and mechanical barriers (cilia, tears).
What are the main cells involved in innate immunity?
Phagocytes (macrophages, neutrophils), natural killer (NK) cells, dendritic cells, mast cells, basophils, and eosinophils.
What do phagocytes do?
They engulf and digest pathogens through a process called phagocytosis.
What is inflammation and why is it important?
A local response to injury or infection; it brings immune cells to the site to destroy pathogens and begin repair.
What are cytokines?
Signaling proteins released by immune cells to coordinate the immune response.
What are the two main types of adaptive immunity?
Humoral immunity (B cells and antibodies) and cell-mediated immunity (T cells).
What makes adaptive immunity different from innate immunity?
It's specific, has memory, and takes longer to activate upon first exposure.
What do B cells do?
Produce antibodies that neutralize pathogens.
What do T cells do?
Helper T cells (CD4⁺) activate B cells and other immune cells; cytotoxic T cells (CD8⁺) kill infected cells.
What are antigens?
Foreign molecules that trigger an immune response.
What are antibodies?
Proteins produced by B cells that bind to specific antigens to neutralize or mark pathogens for destruction.
What is immunological memory?
The immune system's ability to respond more rapidly and effectively to pathogens it has encountered before.
How do vaccines work?
They expose the immune system to a harmless form of the pathogen or antigen to create memory cells.
What is an autoimmune disease?
A condition in which the immune system attacks the body's own tissues (e.g., lupus, rheumatoid arthritis).
What is an allergy?
An overreaction of the immune system to a harmless substance (allergen), often involving histamine release.
What is immunodeficiency?
A weakened immune response, either from genetic causes (e.g., SCID) or acquired (e.g., HIV/AIDS).
What is the role of the lymphatic system in immunity?
It transports lymph, filters pathogens through lymph nodes, and houses lymphocytes.
What are MHC proteins and why are they important?
Major Histocompatibility Complex proteins present antigens to T cells, allowing them to recognize infected or abnormal cells.
What is the difference between active and passive immunity?
Active immunity involves your own immune response (infection or vaccine); passive immunity is gained through antibodies from another source (e.g., mother to baby via breast milk).