Ch. 24 Immune System Flashcards
Neutrophils
a nonspecific defensive, phagocytic white blood cell that can engulf bacteria and viruses in infected tissue; has a multi-lobed nucleus
Monocytes
a phagocytic white blood cell that can engulf bacteria and viruses in infected tissue; has a large oval or horseshoe-shaped nucleus
Macrophages
a large, amoeboid, phagocytic white blood cell that develops from a monocyte
- “Big Eater”
- Wander actively in interstitial fluid to eat bacteria and virus infected cells
Natural Killer Cells
a nonspecific defensive cell that attacks cancer cells and infected body cells, especially those harboring viruses
Interferon
a nonspecific defensive protein produced by virus-infected cells and capable of helping other cells resist viruses
- Short term and most effective against influenza/cold
- Made by body in small quantity, use recombinant DNA
Complement Proteins
a family of nonspecific defensive blood proteins that cooperate with other components of the vertebrate defense system to protect against microbes; can enhance phagocytosis, directly lyse pathogens, and amplify the inflammatory response
Inflammatory Response “setting on fire”
a nonspecific body defense caused by a release of histamine and other chemical alarm signals, which trigger increased blood flow, a local increase in white blood cells, and fluid leakage from the blood. The results include redness, heat, and swelling in the affected tissues.
- Aims to disinfect and clean injured tissues
- Helps to prevent the spread of infection to surrounding tissues
Histamine
a chemical signal released by injured cells that causes blood vessels to dilate during an inflammatory response
Lymphatic System
the organ system through which lymph circulates; includes lymph vessels, lymph nodes, and the spleen. The lymphatic system helps remove toxins and pathogens from the blood and interstitial fluid, and returns fluid and solutes from the interstitial fluid to the circulatory system
Lymph
a fluid similar to interstitial fluid that circulates in the lymphatic system
What are the functions of the lymphatic system?
1) return tissue fluid to circulatory system
2) fight infection
Immune System
the organ system that protects the body by recognizing and attacking specific kinds of pathogens and cancer cells
- More effective than nonspecific resistance → amplifies certain nonspecific responses
- Extremely specific and has remarkable “memory” for antigens it has encountered before → react faster
Antigen
a foreign (nonself) molecule that elicits an immune response
Antibody
a protein dissolved in blood plasma that attaches to a specific kind of antigen and helps counter its effects
Immunity
resistance to specific body invaders
- Acquired by natural infection or vaccination
Vaccination
a procedure that presents the immune system with a harmless variant or derivative of a pathogen, thereby stimulating the immune system to mount a long term defense against the pathogen
Vaccine
a harmless variant or derivative of a pathogen used to stimulate a host organism’s immune system to mount a long term defense against the pathogen
Active Immunity
body is stimulated to produce antibodies in its own defense
Passive Immunity
temporary immunity obtained by acquiring ready-made antibodies or immune cells; lasts only a few weeks or months because the immune system has not been stimulated by antigens
Lymphocytes
a type of white blood cell that is chiefly responsible for the immune response; found mostly in the lymphatic system
B Cells
a type of lymphocyte that matures in the bone marrow and later produces antibodies; responsible for humoral immunity
T cells
a type of lymphocyte that matures in the thymus and is responsible for cell-mediated immunity; also involved in humoral immunity
Humoral Immunity
the type of specific immunity brought about by anti-body producing B cells; fights bacteria and viruses in body fluids
- Antibodies carries in lymph/blood to site of infection
- Can be passively transferred by injecting blood plasma
Cell Mediated Immunity
the type of specific immunity brought about by T-Cells; fights body cells infected with pathogens
- Cannot be transferred passively with plasma but with actual T cells from an immune individual
- T cells work against bacteria, virus, fungi, protozoans
- Work indirectly by promoting phagocytosis by other WBC and by stimulating B cells to produce antibodies
Antigen Receptors
protein molecules produced when certain genes are turned on that are capable of binding one specific type of antigen
Antigen Determinants
A region on the surface of an antigen molecule to which an antibody binds
- Recognized by complementary shapes w/ antigen-bind site
- Antigen has different several determinants → different antibodies can bind to same antigen
Clonal Selection
the production of a lineage of genetically identical cells that recognize and attack the specific antigen that stimulated their proliferation. The mechanism that underlies the immune system’s specificity and memory of antigens.
Primary Immune Response
occurs when lymphocytes are first exposed to an antigen and form a clone of effector cells
- Antibodies start to show up in blood
Secondary Immune Response
A second exposure to the same antigen elicits a faster and stronger response
- Lasts longer than primary immune response
Memory Cells
one of a clone of long-lived lymphocytes formed during the primary immune response; remains in a lymph node until activated by exposure to the same antigen that triggered its formation. When activated, a memory cell forms a large clone that mounts the secondary immune response.
- Survive for decades, remain in lymph nodes
Plasma cells
an antibody secreting B cell
Antigen-binding site
a region of the molecule responsible for the antibody’s recognition-and-binding function
Monoclonal Antibodies
an antibody secreted by a clone of cells and, consequently, specific for the one antigen that triggered the development of the clone
- Descendants of a single cell → identical antibody
- Harvested from cell cultures (not animals)
Cytotoxic T cells
a type of lymphocyte that attacks body cells infected with pathogens
Helper T cells
a type of lymphocyte that helps activate other types of T cells and may help stimulate B cells to produce antibodies
Antigen-Presenting Cells
one of a family of WBC that ingests a foreign substance or a microbe and attaches antigenic portions of the ingested material to its own surface, thereby displaying the antigens to a helper T cell
Self protein
a protein on the surface of an antigen-presenting cell that can hold a foreign antigen and display it to helper T cells. Each individual has a unique set of self proteins that serve as molecular markers for the body. Lymphocytes do not attack self proteins unless the proteins are displaying foreign antigens; therefore, self proteins mark normal body cells as off-limits to the immune system.
Nonself Molecules
a foreign antigen; a protein or other macromolecule that is not part of an organism’s body
Perforin
a protein secreted by a cytotoxic T cell that lyses (ruptures) an infected cell by perforating its membrane
Autoimmune diseases
an immunological disorder in which the immune system attacks the body’s own molecules
Immunodeficiency diseases
an immunological disorder in which the immune system lacks one or more components, making the body susceptible to infectious agents that would ordinarily not be pathogenic
Allergies
a disorder of the immune system caused by an abnormal sensitivity to an antigen; symptoms are triggered by histamines released from mast cells
Allergens
an antigen that causes an allergy
Mast Cells
a vertebrate body cell that produces histamine and other molecules that trigger the inflammatory response)
Antihistamines
a drug that interferes with the action of histamine, providing temporary relief from an allergic reaction
Anaphylactic shock
a potentially fatal allergic reaction caused by extreme sensitivity to an allergen; involves an abrupt dilation of blood vessels and a sharp drop in blood pressure
Non Specific Defense
1st line of defense against invaders
- treats all pathogens/invaders the same
1) Structure
2) Cells
3) Molecules
What are the structures of non specific defense?
1) Skin
2) Ciliated Mucus Membranes
3) Stomach Acids
4) Nostril Hair
What are the cells of non specific defense?
Leukocytes (WBC)
- neutrophils/monocytes
- macrophages
- natural killers
What are the molecules of non specific defense?
Antimicrobial Proteins
- interferons and compliment proteins
What are the steps of the inflammatory response?
1) Damage cells release histamine
2) Dilate blood vessels and make it leaky to release some plasma
3) Plasma flows from interstitial fluid
4) Phagocytes etc. brought to infected area and tissue is cleaned/disinfected
5) Pus left over is the remains of the response composed of cell debris, fluids, and dead WBC
What are symptoms of inflammatory response?
1) Infected area is red due to increase in blood flow as vessel is dilated
2) Swelling due to leaky capillaries
3) Warm due to blood which inhibits micro growth
4) Pain due to swelling against nerves thus cause less damage
What is the reason for limited effectiveness of nonspecific immunity on pathogens?
Slow and unselective
Specific Immunity
Body recognizes/defends against specific invaders
- extreme specificity and long term memory
- often amplifies non specific responses and enhances the compliment protein reaction
- Important aspects: antigen, antibodies, immunity
How do people get HIV (AIDS)
By the exchange of bodily fluids w/ someone who is HIV+
- unprotected sex
- sharing hypodermic needles
- transfusion of infected blood
- mother to child in womb
Who are the 3 groups of people who have AIDS/HIV the most? And who are starting to get it more?
IV drug users, gay men, hemophiliacs
Heterosexual teens and epidemic in Africa
What are the 3 enzymes of HIV?
Reverse transcriptase, integrase, protease
How can we cure AIDS/HIV?
Block a step in the reproductive cycle that is unique to HIV/AIDS but it evolves rapidly
- AZT, AIDS cocktails, HIV Resistant stem cells
