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SAT Biology - The Human Immune System

Terms in this set (46)

What are the two parts of the immune system?
1. nonspecific defense
2. specific defense
What is the nonspecific defense comprised of?
1. First Line of Defense
2. Second Line of Defense
What is the First Line of Defense?
a barrier that helps prevents pathogens from entering the body
What are the different types of barriers in the nonspecific defense?
• skinn*
• mucous membraness*
• ciliaa*
• stomach acid
What does the skin do?
blocks pathogens
What do the mucous membranes do?
release mucus to trap microbes
What do cilia do?
in the respiratory system, sweep out mucus with its trapped microbes
What does stomach acid do?
kill germs that enter through the nose and mouth
What is the Second Line of Defense?
a barrier meant to limit the spread of invaders in advance of specific immune responses
What are the three parts of the Second Line of Defense?
1. inflammatory response
2. phagocytes
3. interferons
What is the inflammatory response?
it is characterized by swelling, redness, soreness, and increased warmth in the area, meant to increase the blood supply to the area, thus increasing nutrients, oxygen, and white blood cells to fight the disease
What are the two ways that the inflammatory response works?
1. histamine
2. increased body temperature
What does histamine do?
triggers the inflammatory response through vasodilation (enlargement of blood vessels), which increases blood supply to the area, bringing more phagocytes to gobble up germs (it's responsible for the symptoms of the common cold to rid the body of invaders)
What does increased temperature do?
1. speed up the immune system
2. makes it more difficult for microbes to function
What are phagocytes?
they gobble up invading microbes (i.e. macrophages are a type of white blood cell that extend pseudopods and engulf huge numbers of microbes over a long period of time)
What are interferons?
chemicals released by the immune system to block against viral infections
What is the specific defense comprised of?
Third Line of Defense
What are the two parts of the specific defense (aka Third Line of Defense)?
1. B lymphocytes
2. T lymphocytes
What are some common characteristics of B & T lymphocytes?
• both originate in the bone marrow
• both circulate in the blood,lymph, and lymphatic tissue once mature
• both recognize different specific antigens
What comprises the lymphatic system?
• spleen
• lymph nodes
• tonsils
• adenoids
What do B lymphocytes do?
produce antibodies against a specific antigen in what is called a humoral response
What do T lymphocytes do?
fight pathogens in hand-to-hand combat in what is called a cell-mediated response, they attack and kill infected body cells
How do antibodies work?
each antibody has the ability to bind to only one particular antigen. antibodies neutralize antigens by binding to them and forming an antigen-antibody complex that can be gobbled up by a phagocyte
What is clonal selection?
A fundamental mechanism in the development of immunity. Once a specific lymphocyte has attached to an antigen, it becomes metabolically active, proliferates, and differentiates into plasma cells and memory cells
What are plasma cells?
cells that fight immediately in the primary immune response, they die in battle
What are memory cells?
they fight the same antigens that plasma cells do, but they remain circulating in the blood in small numbers for a lifetime. We have memory cells circulating in our blood specific for every viral infection we've ever been ill with.
What is immunological memory?
the capacity of the immune system to generate a secondary immune response that prevents us from getting any specific viral infection more than once.
What are the two types of immunity?
1. passive immunity
2. active immunity
Is passive immunity temporary or permanent?
temporary
What are some characteristics of passive immunity?
• antibodies are borrowed and do not survive for long
• examples are maternal antibodies that pass through the placenta to the developing fetus
Is active immunity temporary or permanent?
permanent
What are some characteristics of active immunity?
• antibodies are made by the individual upon:
1. being ill and recovering
2. being given an immunization or vaccine
What is a cross match?
when samples of the recipient and donor's blood are mixed in the lab to determine and ensure compatibility of blood transfusion
What antigens do each blood type have?
each blood type has antigens corresponding to its name (i.e. Blood type A has A antigens on the surface of its red blood cells)
A person with what blood type is the universal donor?
O
A person with what blood type is the universal recipient?
AB
How does HIV destroy the immune system?
it attacks helper T cells
What are allergies?
hypersensitive immune responses to certain substances called allergens
What do allergies "release" in the body?
excessive amounts of histamine, an anti-inflammatory agent, causes the blood vessels to dilate
What are the symptoms of a normal allergic reaction?
redness, runny nose, itchy eyes
What can normally counteract the symptoms of allergies?
anithistamines
What is anaphylactic shock?
a life threatening allergic response that can result in death in minutes
What causes autoimmune diseases?
the failure of the immune system to distinguish between self and nonself
What are some examples of auto-immune diseases?
• multiple sclerosis
• lupus
• rheumatoid arthritis
• juvenile diabetes
Is AIDS an autoimmune disease?
no, because it is caused by HIV; in addition, the disease does not cause the immune system to attack the body, but instead suppresses the immune system itself
What causes multiple sclerosis?
when the immune system attacks the myelin sheath surrounding certain neurons
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