Immune system and the Bodys Deffenses questions Flashcards
Unit 1 A&P
Define Infectious Agent
things that cause disease or damage to host
What are the five major categories of infectious agents?
Bacteria
Viruses
Fungi
Protozoans
Multinucelluar parasites
Describe Bacteria
- prokaryotic
- single cell
- lack nuclear envelope
-Strep throat, Staph infection
Describe Viruses
- not a cell
- made from DNA/ RNA in a shell
- obligate intracelluar parasites
- COVID, Common cold
Describe Fungi
- Eukaryotic
- Uni/Multi cellular
-makes spores - releases prolytic enzymes
- Molds, diaper rash
Describe protozoans
- Eukaryotic
- lack cell wall
- unicellular parasites
- messes w/ normal cell function
- Malaria
Describe Multicellular parasites
- Eukaryotic
- Multicellular
-Live in host - tape worms
Describe a Prion and name a disease they causes, Why?
- Small disease-causing protein
- Mad cow
prions transfer from cows to humans as they eat the meat
Define specific and nonspecific defense.
Specific defense
- not born with
- body fights off things we are exposed to over a lifetime
- eliminates foreign substance
Nonspecific Defense(Innate)
-Born with
- protects us from many substances
-skin, mucous membranes, T/ B lymphocytes
Which of the two does NOT depend on prior exposure to the pathogen?
innate/nonspecific defense
How is the first line of defense different from the second line of defense?
First line
- prevents entry of pathogens
- nonspecific defense
-skin and mucous membranes
Second line
- nonspecific internal defense
- effective for a wide range of pathogens
What is produced during the first line of defense in the skin and mucous membranes that provides protection?
mucous
Define cytokines
- small soluble proteins made by cells of innate and adaptive immunity
What are the three second lines of defense?
- cellular defense
- Antimicrobial proteins
- Inflammation
Define phagocytosis
- non specific
- neutrophils and macrophages go to an infected area to remove debris
- pathogen gets trapped in phagosome, fuses to lysosome to form phagolysosome
What is the process of phagocytosis
- Chemotaxis
- Adherence
- Ingestion
- Digestion
- killing
understande the 5 processes in phagocytosis.
Name the cells involved in cellular defense.
Neutrophils
Macrophages
Fixed and wondering macrophages
Dendritic Cells
Basophils & Mast cells
Eosinophils
NK cells
Where are Neurophils formed? Travel to?
Bone Marrow
- blood then tissues
Where are macrophages formed? Travel to?
extracellular matrix between cells
Where are fixed and wandering macrophages formed? Travel to?
bone marrow
blood as a monocyte
Dendritic cells are formed where? Travel to?
Bone marrow
-peripheral tissues
Basophil and mast cells are formed where?Travel to?
Bone marrow
blood and tissue
eosinophils are formed where? Travel to?
Bone marrow
-mucous of respiratory, digestive and lower urinary tracts
where are NK cells formed and where do they travel to
bone marrow
-lymphoid organs, liver,lungs
Understand antigen presentation by macrophages.
programmed to look for and eat foreign particles between cells
How are fixed macrophages different from wandering macrophages?
Fixed
- sets up houses in a tissue to monitor for pathogens
Wandering
- moves in/out of blood and lymph to monitor pathogens
Where can fixed macrophages be found?
Macrophages of loose connective tissue
- Microglia in CNS
- Hepatic macrophages in liver
- Areolar macrophages in lungs
What is a dendritic cell?
Phagocytic cells of skin and mucous membrane
What is the difference between a basophil and mast cell?
Basophil
-circulate blood
Mast Cells
- in CT of skin, mucosal linings and internal organs
What chemicals are secreted by basophils and mast cells?
histamine
heparine
eiosanoids
What is a NK cell?
Cells that starts apoptosis
How do NK cells destroy cells?
gives perforin and granzyme to start apoptosis of infected cells
antimicrobial protein provide…
short term, nonspecific resistance
what do histamines do?
increase blood flow
speeds up leukocytes to certain area
what does heparin do?
stops formation of clots
eicosanoids increase…
inflammation
What are the 2 kinds of antimicrobial proteins?
interferons and Complement
Define interferon.
cytokine
signaling proteins made and released by cells that have been invaded by a virus
How do interferons work?
- infected cell secretes interferon
- interferon diffuses stimulating close cells to make antiviral proteins(PKR)
- The virus is prevented from multiplying
What are the different types of Interferons?
-Type I( alpha/Beta)
- Type II( Gamma y)
- Type III( upside down y)
What is the complement system?
30+ globulins that aid in nonspecific resistance and specific immunity
How many plasma proteins are in the complement system?
60
Know the difference between the classical pathway, alternative pathway and lectin pathway.
Classical Pathway
- C1 binds to antigen - antibody complexes
- C2 and C4 split forming C2b, C2a, C4b and C4a
- C2a and C4b join to form C3
- C3 is split to C3a and C3b
- C3a stimulates inflamtaion
- C6, C7, C8 and C9 associate to form MAC causing cell lysis
Alternative pathway
- Factor B, factor D, factor P and C3b bind to cell walls polysaccharides to activate C3b
- C3 undergoes autolysis for C3b that is unstable
- Factor B stabilizes C3b
- Factor D cleaves factor B to make C3b factor Bb( acts as convertase)
- Properdin, factor P stabilizes C3b facotr Bb C3 convertase
What is the job of C1 in the complement system?
activates
the 3 functions of inflamation are…
- limit/ destroy pathogens
- remove debris of damaged tissue
- start tissue repair
What triggers the inflammatory response?
injury of any kind
What are the chemicals involved in inflammation?
Histamine
Leukotriens
prostaglandins
Interleukins
TNF
What are the four cardinal signs of inflammation?
Redness
swelling
heat
pain
Define margination.
CAMs on leukocytes attach to CAMs on endothelial cells of injured tissue
Define emigration (diapedesis).
when leukocytes squeeze out between endothelial cell walls and travel to destination of infection
What are the first cells that react ( are on the scene) to an inflammatory reaction?
neutrophils
What are the second cells that react (are on the scene) to an inflammatory reaction?
Monocytes
How is fever beneficial?
helps innate immunity and inflammatory response
What is a pyrogen?
fever inducing molecules
What prostaglandin is released during a fever that raises the setpoint?
PGE2
What are the three characteristics of specific defense?
Specific - directed against pathogen
systemic- not restricted to the certain infection site
memory - when re-exposed body same pathogen reacts stronger
Define humoral and cellular immunity
humoral
- release of antibodies from plasma cell
cellular
- immune response w/ t lymphocytes
Which form of immunity is based on the action of lymphocytes that directly attack cells?
Celluar immunity
Name the three cells involved in adaptive immunity.
T lymphocytes
B lymphocytes
cytoxic T cells
Define an epitope (antigenic determinants).
portions or fragments of antigens
What two things bind to these sites?
B cells and T cells
What are MHC proteins? What role do they play in specific defense?
plasma membrane proteins that mark cells as self to present antigens
they present self and non self peptide antigens to T cells
What are the two major groups of MHC proteins and what cells are they found on?
MHC class I - nucleated cells
MHc clas II - Antigen presenting cell(APC)
Define immunocompetent. Define clonal selection
immunocompetent- able to bind to foreign antigens and respond
Clonal selection- on binding antigen, the cell is activated to divide and produce clones
Where do T cells become immunocompetent? B cells?
T cells - thymus
B cells - red bone marrow
Understand positive and negative selection of T cells. Define anergy.
anergy- the absence of reaction to an antigen
positive- t cells in the thymus that bind moderately to MHC stay positive
Negative T cells- t cells that bind strongly to MNC self react and are killed
Define APC. Which cells are APCs?
antigen-presenting cells
macrophages, B cells and dendritic cells
What is the difference between a complete and incomplete antigen?
Complete antigen- starts an immune response and reacts w/ products from it
Incomplete antigen- unable to start immune reaction but can link w/ carrier proteins
Know the types of substances that act as complete and incomplete antigens.
complete- glycoproteins, lipoproteins, immune response
incomplete- peptides, nucleotides, hormones, household products
What is a hapten?
small substances that attach to another molecule to initiate immune reaction
Define immunogenicity. Define reactivity.
immunogenicity- the ability to cause an immune response
reactivity- antigen reacts specifically to antibodies it provokes
What are the principal cells in humoral immunity?
B cells
Know the three stages in humoral immunity.
B cell activation
Antibody secretion
Antigen elimination
What triggers B cells to undergo clonal selection?
when it comes across a antigen that fits the specific antigen receptor
What does a B cell give rise to when undergoing clonal selection?
antibodies into the blood
What are the five classes of immunoglobulins?
IgA
IgE
IgD
IgG
IgM
Know the function of each immunoglobulin
What are the four defense mechanisms used by antibodies to form an antigen-antibody complex?
Know the function of each mechanism.
How many days after the primary response do antibodies begin to appear?
3-6 days
Which cells are formed during the primary response that can mount a quick secondary response?
B cells
Which immunoglobulin responds first during a primary response and which responds second?
IgM
What are the two main T cells that are involved in cellular immunity?
Helper T cells
cytoxic T cells
Which of those are CD8 and which are CD4?
Cytoxic- CD8
Helper- CD4
When an APC encounters and processes a foreign antigen, who does it present the foreign antigen to in the lymph node?
ag-MHCP to a CD4 cell( helper T)
Understand co-stimulation.
when a Th/Tc binds to MhCP the T cell epitope must bind to another site before another response can happen
What is the function of interleukins in the attack stage of cellular immunity?
slows down immune response
What are autoantibodies and what role do they play in autoimmune disease?
attacks the body’s own tissue
What are the three reasons why self-tolerance may fail?
