Chap 29 The Immune System Flashcards
What is the immune system’s main job?
to prevent illness
What is the immune system?
a widespread collection of cells and chemicals that defend the body against infections, cancer, and foreign substances
What are the different components of the immune system?
white blood cells
lymphatic system
defensive proteins and chemicals
What is the purpose of white blood cells?
to defend the body
What are the three types of white blood cells?
phagocyte
lymphocyte
basophil
What is the function of phagocyte?
engulf bacteria and debris
What is the function of lymphocyte?
coordinate immune response; attack infected or cancerous cells
What is the function of basophil?
tigger inflammation
What is the purpose of the lymphatic system?
produces and stores defense cells
What are the lymphoid organs?
spleen
thymus
bone marrow
What is the function of the spleen?
produces and stores white blood cells
transports defense cells
filter out foreign substances
What is the function of the thymus?
where T lymphocytes mature
What is the function of bone marrow?
produces variety of blood cells
What is the lymph?
the colorless fluid of the lymphatic system
What is the purpose of the lymph capillaries?
absorb interstitial fluid and deliver it to larger lymph vessels
The lymph passes through what?
the lymph nodes
What do the lymph nodes do?
remove foreign substances from lymph
Each lymph node contains millions of what?
lymphocytes
What are the two subdivisions of the immune systems?
innate defense
adaptive immunity
What does innate defense do?
provide broad defense against any pathogen
What does adaptive immunity do?
immune cells recognize and remember specific pathogens
Innate defenses are…?
immediate and nonspecific
What forms the first line of defense?
physical and chemical barriers
What does the first line of defense do?
block pathogens and foreign substances from entering the body
What are the physical and chemical barriers forming the first line of defense?
skin mucus ear wax tears stomach acid
Various cell types participate in internal what?
innate defense
What do macrophages do?
consume pathogens and promote fever
What do natural killer cells do?
destroy body cells that have become cancerous or infected with a virus
What do basophils do?
provoke inflammation by releasing histamine
What participates in internal defense?
antimicrobial proteins
White blood cells produce what?
complement proteins
What do complement proteins do?
puncture bacterial cell membranes
What are cytokines?
proteins that can cause a rise in the body’s temperature called fever
High body temperature indirectly counters what?
microbial growth
Inflammation is a what?
internal innate defense
What is inflammation?
an immediate response that recruits white blood cells to the area, helps clear debris, and creates an environment hostile to microbes
Adaptive immunity is triggered by what?
antigens
What are antigens?
molecules at the surface of bacteria, viruses, and other “invaders” of the body
What do antigens do?
stimulate an immune reaction by B cells and T cells
What are antibodies?
Y-shaped proteins produced by the immune system that bind to specific antigens as part of the immune response
What engulfs invaders and save their antigens for later?
macrophages
What presents the antigens to lymphocytes?
macrophages
What do helper T cells do?
divide and differentiate
What do memory and effector T cells do?
play different roles in adaptive immunity
What is able to launch a quick immune response if the antigens enters the body again?
memory cells
they “remember” antigens the immune system has already encountered
What acts immediately, releasing cytokines that help activate and enhance the cell-mediated and humoral immune responses?
effector helper T cells
What do cytokines do?
initiate cell-mediated and humoral immune responses
What are cytokines?
messenger proteins that bind to immune cells and alter their activity
How do cytotoxic T cells attack and destroy?
the cytotoxic T cells bind to antigens on bacteria, caner cells, or virus-infected cells, then release toxic chemicals that kill the cell
What are the main weapons of humoral immunity?
antibodies
What is the function of antibodies?
to attack pathogens in the body’s fluids (but not inside infected cells)
Each antibody is made to recognize what?
one antigen
The primary immune response can be what?
slow
The primary immune response is the adaptive immune system’s what?
first reaction to a foreign antigen
It can take how long to produce enough antibodies to clear up an infection?
weeks
during this time the infection can cause severe damage or even death
What jump-start immunity?
vaccines
What does a vaccine do?
stimulates active immunity against a pathogen without causing illness
What do the antigens in the vaccine do?
teach the immune system to recognize invaders
What do vaccines consist of?
antigens from inactivated viruses
or
other pathogens to stimulate a primary immune response in the body
What lingers after the initial exposure to the antigens in the vaccine?
memory cells
What happens if an individual that is vaccinated is later exposed to the real pathogen?
a strong secondary immune response will occur
Most vaccines do not contain what, and therefore cannot cause the disease they are designed to prevent?
live pathogens
What are the different forms antigens take in vaccines?
live, weakened (attenuated) pathogen
inactivated pathogen
inactivated toxin
subunits of pathogens
Vaccines cannot do what?
prevent all infectious diseases
Why is there no vaccine for HIV/AIDS?
because it mutates so rapidly
Why do flu vaccines have limited effectiveness?
because the flu viruses evolve new antigens each season
What happens in the immune system when a person has an autoimmune disorder?
the immune system attacks the wrong cells
What happens if colonial deletion fails?
the immune system mistakenly attacks the body’s molecules
What happens in Type 1 diabetes?
antibodies attack insulin-producing cells in the pancreas
What causes arthritis?
an autoimmune attack on the cells lining the skeletal joints
What misdirects the immune response?
allergies
What are exaggerated immune responses to harmless substances?
allergies
Allergies do what?
launch and exaggerated attack
What happens in allergies if the body is exposed to the same pollen antigen again?
mast cells release histamine and other chemicals that cause an allergic reaction
