Exam 3- Chapter 15 Flashcards
What do defense mechanisms protect against?
Protect against disease-causing agents called pathogens
What do defense mechanisms make up?
Immune system
How many types of defense mechanisms are there? Name them.
- Innate (nonspecific) immunity
2. Adaptive (specific) immunity
What is another name for innate immunity?
nonspecific immunity
What is another name for adaptive immunity?
specific immunity
Are there strict “borders” for innate/adaptive immunity, or is there some overlap?
There are some areas of overlap between the two
Which type of immunity serves as as a first line of defense against pathogens?
Innate (nonspecific) immunity
Which type of immunity is inherited?
Innate (nonspecific) immunity
Name 4 examples of Innate (nonspecific) immunity?
- Epithelial membranes
- High acidity in stomach
- Cells that can engulf/kill pathogens
- Fever
When discussing the activation of innate (nonspecific) immunity, how do cells distinguish “self” from “nonself”?
pathogen-associated molecular patterns (PAMPs) unique to the pathogens
Immune cells have toll-like receptors for PAMPs on their _____.
surface
How many types of toll-like receptors have been identified?
10
How do toll-like receptors respond to pathogens?
These cells respond by secreting cytokines to recruit more immune cells or activate specific immune cells
Are lipopolysaccharides gram +, or gram -?
gram -
Is peptidoglycan gram +, or gram -?
gram +
How many types of phagocytic cells are there?
3
Name the 3 types of phagocytic cells.
- Neurotrophils
- Mononuclear phagocytic cells
- Organ-specific phagocytes
In phagocytosis, which cells are the first to arrive at an infection? What cells arrive later?
- Neutrophils
2. Mononuclear phagocytic cells
What are the two types of Mononuclear phagocytic cells , and where are they located?
- monocytes in the blood
2. macrophages in the tissues
Where are organ specific phagocytes found?
liver, spleen, lymph nodes, lungs, and brain
Some of the organ-speicifc phagocytes are called fixed phagocytes. What does this mean?
They are immobile in the walls of these organs
Organ-specific phagocytes can be considered part of what other type of phagocytic cells?
Mononuclear phagocytic cells
Neurotrophils and monocytes participate in a process called extravasation/diapedesis. What does this mean?
Neutrophils and monocytes squeeze through gaps in venule walls to enter tissue in a process called extravasation, or diapedesis
What are Neurotrophils, and monocytes attached to the site by?
Attracted to site by cytokines
Summarize phagocytosis in 3 steps.
- The pathogen becomes engulfed by pseudopods.
- The vacuole containing the pathogen fuses with a lysosome.
- The pathogen is digested.
What is fever regulated by?
hypothalamus
What chemical sets the body temperature higher?
endogenous pyrogen
Why is endogenous pyrogen produced, and by what?
- Toxins from some bacteria stimulate leukocytes to produce these cytokine
- Produced as a cytokine by leukocytes
Along with a fever, what does endogenous pyrogen induce?
Along with fever, they also induce sleepiness and a fall in plasma iron concentration (which limits bacterial activity).
What are interferons?
Antiviral polypeptides produced by infected cells
How many types of interferons are there? Name them.
3 types:
- Alpha
- Beta
- Gamma
New antiviral drugs are being developed using what?
interferons
Unlike innate (nonspecific) immunity which is inherited, how is adaptive (specific) immunity acquired?
The acquired ability to defend against specific pathogens after exposure to these pathogens
What is adaptive (specific) immunity mediated by?
Mediated by antigens and antibodies
What are antigens?
Cell surface molecules that stimulate the production of specific antibodies
What do foreign antigens illicit?
Foreign antigens illicit an immune response. The immune system can distinguish “self” from “nonself.”
What do antibodies bind to?
Antibodies bind to their specific antigens
Large molecules can have several antigenic determinant sites. What do these stimulate?
Large molecules can have several antigenic determinant sites that stimulate the production of and binding to antibodies.
What are haptens?
Smaller, nonantigenic molecules that can become antigens when bound to other proteins
What are haptens useful for?
These are useful for creating antigens for research and diagnosis.
What are immunoassays?
Tests that use specific antibodies to identify specific antigens
What are immunoassays used for?
Used to determine blood type and detect pregnancy
In immunoassays, what does binding cause?
Binding causes agglutination, which can be seen.
What are lymphocytes derived from?
Derived from stem cells in the bone marrow
The stem cells in the bone marrow in which lymphocytes are derived from seed what organs?
These stem cells seed the thymus, spleen, and lymph nodes
Through late childhood, what is the site of new T lymphocytes? What happens in late adulthood?
- The thymus is the site of new T lymphocytes through late childhood.
- It degenerates in adulthood, and new T lymphocytes are made through mitosis in secondary lymphoid organs.
What are considered primary lymphoid organs?
- Bone marrow
2. Thymus
Lymphocytes that seed the thymus become what? What do these then seed?
- T lymphocytes
- These then seed the blood, lymph nodes, and spleen
What do T lymphocytes attack?
- Host cells that have become infected with a virus or fungus
- Transplanted human cells
- Cancer cells
Do T lymphocytes produce antibodies?
NO
Where must T lymphocytes be in proximity to the victim cell in order to destroy them? What is this called?
- They must be in close proximity to the victim cell in order to destroy it.
- Cell-mediated immunity
Lymphocytes that come directly from bone marrow to seed other organs (not the thymus) are called what?
B lymphocytes
What do B lymphocytes combat?
They combat bacterial and some viral infections
Do B lymphocytes produce antibodies?
YES
Where must b lymphocytes be in proximity to the victim cell in order to destroy them? What is this called?
- They secrete antibodies into blood and lymph so can be far from the victim
- humoral immunity or antibody-mediated immunity.
Where do B lymphocytes secrete antibodies?
They secrete antibodies into blood and lymph
Name the 4 secondary lymphoid organs?
- Lymph nodes
- Spleen
- Tonsils
- Peyer’s patches (in mucosa of intestines)
What is the function of the secondary lymphoid organs?
Capture and present pathogens to macrophages and house lymphocytes
Lymphocytes migrate between lymphoid organs to sample what?
blood and lymph
What secondary lymphoid organ filters blood for pathogens? What secondary lymphoid organ filters lymph for pathogens?
- The spleen filters blood for pathogens
2. Other organs filter lymph for pathogens
When does local inflammation occur?
Occurs when bacteria enter a break in the skin
What is local inflammation initiated by?
Initiated by nonspecific mechanisms of phagocytosis by toll-like receptors
Local inflammation is initiated by nonspecific mechanisms of phagocytosis by toll-like receptors. What two things will happen next?
- Macrophages and mast cells release cytokines to attract phagocytic neutrophils.
- Complement proteins are activated, which also attract phagocytic cells.
In local inflammation, after complement proteins are activated (which also attract phagocytic cells), what happens as inflammation progresses?
- As inflammation progresses, B lymphocytes produce antibodies against bacterial antigens
- Formation of antigen-antibody complexes amplifies nonspecific response, a process called opsinization
What is opsinization?
Formation of antigen-antibody complexes amplifies nonspecific response (can be seen in local inflammation)
In local inflammation, after opsonization, what two things happen next?
- More phagocytic cells arrive via extravasation from nearby venules. T lymphocytes are the last to arrive.
- Neutrophils may spill protein-digesting enzymes into the surrounding tissues, causing pus
- Mast cells secrete heparin, histamine, prostaglandins, leukotrienes, cytokines, and TNF-α. They also recruit more leukocytes.
In local inflammation, mast cells secrete heparin, histamine, prostaglandins, leukotrienes, cytokines, and TNF-α. What does this produce?
These produce warmth, swelling, and pain (classic symptoms)
In local inflammation, mast cells secrete heparin, histamine, prostaglandins, leukotrienes, cytokines, and TNF-α. What do they also recruit?
They also recruit more leukocytes.
How are B lymphocytes activated?
Exposure to the specific antigen activates a B lymphocyte and causes it to undergo multiple cell divisions
After B lymphocytes are activated, what are two possible things that they can become?
- Some become memory cells, which are used in a later infection by the same pathogen
- Others become plasma cells, which produce 2,000 antibodies/second
When B lymphocytes become plasma cells, how many antibodies can they produce per second?
2,000 antibodies/second
What are antibodies also known as?
immunoglobulins
How many classes of antibodies/immunoglobulins are there?
5
Name the different classes of antibodies/immunoglobulins.
IgG, IgA, IgM, IgD, and IgE