Q: Where are WBCs produced?
A: In the bone marrow.
Q: What are the two main lymphocytes and their roles?
A: B cells (humoral response) and T cells (cell-mediated response).
Q: What is the function of the spleen?
Acts as a filter:
Red pulp → removes old/injured RBCs
White pulp → stores lymphocytes.
Q: What is the function of lymph nodes?
A: Filter lymph, remove foreign material before it enters the bloodstream.
Q: What is natural immunity?
A: Nonspecific, first-line defense present at birth; immediate (minutes) or delayed (days).
Q: What are the barriers of natural immunity?
A: Physical (skin, mucous membranes, cilia), chemical (mucus, gastric acid, tears, saliva enzymes, sweat).
Q: What happens if natural immunity fails?
A: Host is considered immunocompromised.
Q: What is acquired immunity?
A: Develops after exposure to an antigen (disease or vaccination); body “remembers” antigens for future defense.
Q: What are the two types of acquired immunity?
Passive acquired (short-term, from immunization or maternal antibodies)
Active acquired (long-term, developed by person’s own immune system).
Q: What are the three responses to invasion?
Phagocytic (ingests foreign particles, removes dead cells)
Humoral/antibody (B lymphocytes → antibodies)
Cellular (T lymphocytes → cytotoxic T cells).
Q: What are the 4 stages of immune response?
A: Recognition → Proliferation → Response → Effector.
Q: What do B lymphocytes do in humoral immunity?
A: Produce antibodies (may need help from T cells).
Q: What conditions are associated with humoral responses?
A: Phagocytosis, anaphylaxis, allergies, immune complex diseases, bacterial/viral infections.
Q: What do T lymphocytes recognize antigens with the help of?
Macrophages
Q: What conditions are associated with cellular responses?
A: Transplant rejection, delayed hypersensitivity, graft vs host, tumor surveillance, intracellular infections (viral, fungal, parasitic).
Q: What are Helper T cells (CD4) responsible for?
A: Secrete cytokines, activate B cells, cytotoxic T cells, NK cells, macrophages.
Q: What are Cytotoxic T cells (CD8) responsible for?
A: Directly attack and destroy antigens.
Q: What are Suppressor T cells responsible for?
A: Decrease B cell production to regulate immune response.
Q: What is the function of Memory cells?
A: Recognize antigens from past exposure to mount faster immune responses.
Q: What is the complement system?
A: A cascade of proteins in the inflammatory process that defend against bacteria, bridge natural/acquired immunity, and dispose of immune complexes.
Q: What are autoimmune disorders caused by?
A: Defects in the complement cascade.
Q: What are interferons?
A: Natural antiviral proteins that activate components of the immune system.
Q: What are colony-stimulating factors?
A: Cytokines that regulate production and activation of hematopoietic cells.
Q: What are monoclonal antibodies?
A: Lab-produced antibodies that target specific organisms, destroy pathogens while sparing normal cells.