Immune System Flashcards
What is the immune system?
- Protects body from harmful pathogens
- Differentiate between individual’s own cells and those of pathogens
- Made up of INNATE AND ADAPTIVE immune systems
Who invented the smallpox vaccine and how did they do it?
EDWARD JENNER
- Noticed that people who contracted cowpox were immune
- Innoculated a child using experimental vaccine (he gave the child a house as a reward)
Who is Louis Pasteur and what did he do?
- Discovered germ theory
- Developed vaccines for cattle anthrax, rabies etc.
What is the evidence for effectiveness of immunisation?
- Eradication of smallpox
- 100% decrease in poliovirus
- 99% decrease in MMR
Describe the origin of immune cells.
- Blood stem cells
- Progenitor cells (lymphoid and myeloid)
- Immune cells (lymphoid progenitor cells produce lymphocytes/ myeloid produce RBCs, phagocytes, mast cells etc.)
Describe the primary lymphoid organs.
- Bone marrow - where most immune cells are produced and multiply
- Thymus - site of maturation of T cells
Describe the secondary lymphoid organs
- Lymph nodes, spleen and tonsils
- Networks of nodes connected by lymphatic vessels
- Lymph nodes contain immune cells - B/T lymphocytes, phagocytes
- Pathogens filtered and destroyed before lymph returns to bloodstream
What happens in immune over-reactions?
- Allergic Responses
- Autoimmune Problems
What can immune under-reactions occur?
- Cancer
- Infections
What are the nonspecific defence mechanisms i.e the first and second lines of defense?
FIRST LINE OF DEFENSE - Skin, mucous membranes
SECOND LINE OF DEFENSE - INNATE IMMUNITY: Phagocytes, inflammatory response by cytokines, macrophages
What are the specific defence mechanisms i.e the third line of defense?
ADAPTIVE IMMUNITY
- LYMPHOCYTES
- ANTIBODIES - made by plasma cells (HUMORAL IMMUNITY)
- CELLULAR IMMUNITY - T cells that mediate responses using receptors
Outline the first line of defence.
- Keratinocytes in skin secrete defensins. Many immune cells e.g mast cells reside in skin
- Cornea - neutrophils kill pathogens here by phagocytosis
- Mucosa of respiratory, GI and GU tracts - mucus contains antimicrobials such as lysozyme, SIgA
Give examples of active and passive naturally acquired immunity.
- ACTIVE - Antigens naturally enter body. Innate/adaptive immune systems respond and provide long-term protection
- PASSIVE - Passage of antibodies from mother to fetus across placenta/through breast milk. Provides short-term protection
Describe active and passive artifically acquired immunity.
- ACTIVE: Vaccination - provides long-term protection
- PASSIVE: Antibodies from immune individuals injected into body. Provides short-term protection
Why is it important for rapid responses such as the innate immune system to occur?
- Bacteria divide very quickly and can spread infection quickly
