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Overview
L1,L2, L3
82
Veterinary Medicine
Professional
01/13/2015

Additional Veterinary Medicine Flashcards

 


 

Cards

Term
What are the three defenses against pathogens?
Definition
-physical barriers
-innate immunity
-adaptive immunity
Term
Compare the relative size of mucosa and skin. Why is this relavent?
Definition
-mucosa comprises 400 sq m
-skin is 2 sq m
-thus this is where pathogens enter
Term
What are the 3 direct functions of innate immunity?
Definition
-induce cytokine secretion and inflammation: activated macrophages alert immune system via secretion of cytokins
-destroy extracellular pathogens: phagocytosis (neutrophils/macrophages) or lysis (complements)
-destroy intracellular pathogens: apoptosis via natural killer cells
Term
Compare/contrast innate and adaptive immunity
Definition
-innate immunity comes at birth without memory and does phagocytosis/lysis
-adaptive immunity: comes from memoryand causes apoptosis
Term
True or False: The innate immune system directs the adaptive immune system.
Definition
TRUE
Term
What are the 2 divisions of adaptive immunity?
Definition
-Humoral immunity via B-cells: antibodies
-Cell-mediated immunity (CMI) via T-cells: cytotoxic lymphocytes kill virus infected cells directly OR T-helper cells "activate" immune cells via secretion of Cytokines
Term
What is the main function of neutrophils and macrophages? Which is more important regarding this function?
Definition
-kill pathogens by phagocytosis
-NEUTROPHILS ARE FAR MORE IMPORTANT IN PHAGOCYTOSIS
Term
Briefly describe the process of phagocytosis.
Definition
-phagocytes extend pseudopods that reach out, grab, and pull in pathogens for phagocytosis
Term
Why is opsonization important?
Definition
-it enhances phagocytosis
Term
Describe opsonization.
Definition
-like dipping a French fry/bacteria into ketchup/Ab or complement proteins that increases the rate of phagocytosis
Term
Definition: Phagosome
Definition
-cytoplasmic vesicle that engulf pathogens after phagocytosis
Term
What is the difference b/n lysosomes and phagolysosomes?
Definition
-lysosomes are pockets of enzymes inside cells
-phagolysosomes are lysosomes that have fused with phagocytosed material to kill the pathogens
Term
Lysosomes contain many enzymes, most importantly _______. Define the blank.
Definition
-acid hydrolases
-hydrolyze and break down covalent: ex: lysozyme, lipases, proteases
Term
After phagocytosis, lysosomes fuse with _________ to form _________, in which pathogens are digested and destroyed.
Definition
-phagosomes
-phagolysosomes
Term
Where do neutrophils originate?
Definition
-bone marrow
Term
Describe the half-life of neutrophils.
Definition
-very short, only 3 days
Term
The majority of the time, where are neutrophils located? When does this change?
Definition
-in the blood stream
-enter tissues IFF there is an infection
Term
What signals neutrophils to enter tissues in the case of an infection?
Definition
-cytokines
Term
What happens to neutrophils once the phagocytose pathogens (primarily bacteria)?
Definition
-once neutrophils leave the blood vessels, they never return, they die in tissues
Term
What does PRR stand for?
Definition
-Pattern Recognition Receptors
Term
What does TLR stand for? What is it an example of?
Definition
-Toll-like receptors
-ex of pattern recognition receptors (PRR)
Term
Definition: PAMP
Definition
-pathogen-associated molecular pattern
-the pathogen structural molecules recognized by PRRs
Term
_______ are by far the most important component of the innate immune system.
Definition
-Macrophages
Term
What is the specialized name for macrophages in the following tissues:
a) liver
b) lungs
c) connective tissue
d) brain
Definition
a) Kupffer cells
b) alveolar macrophage
c) histiocytes
d) microglial cells
Term
What are the 3 functions of macrophages?
Definition
-secrete cytokines to alert and attract other immune cells to the area of infection
-phagocytize and kill pathogens
-macrophages also present parts of the broken down pathogens to other immune cells: act as antigen presenting cells
Term
What does APC stand for? Example?
Definition
-antigen presenting cells (APC)
-ex: macrophages
Term
True or False: Similar to neutrophils, macrophages die after activation.
Definition
FALSE, they return to resting state
Term
What are cytokines and what do they do?
Definition
-small hormone-like molecules secreted by a variety of immune cells including macrophages
-they bind to receptors on other immune cells thereby regulating their function: they allow immune cells to talk to each other
Term
Describe the function of Natural Killer cells
Definition
-they hunt for and recognize "abnormal" (stressed, infected, or transformed) and KILLS them
Term
How do NK cells work?
Definition
-they secrete molecules that bind to death proteins in the celld, inducing programmed cell death/apoptosis
Term
What is Perforin? What cells use it?
Definition
-perforin is a pore-forming enzyme
-NK cells release perforin to form a pore in the target cell's membrane, through which granzyme B enters to trigger caspase (death molecule) that enters the nucleus and breaks up the cell DNA
Term
True or False: NK cells die after doing their job.
Definition
FALSE
Term
Why is apoptosis preferable is areas such as the brain and lungs?
Definition
-cells die without inflammation
Term
Briefly describe the complement system.
Definition
-complement creates pores in the cell membrane that results in cell lysis
Term
Briefly outline the innate immune system
Definition
-responds very fast, cytokines are released by macrophages within minutes of an infection
-recognizes PAMP molecules (basic structural components on pathogens)
Term
Where do T-cells mature? B-cells?
Definition
-T-cells= thymus
-B-bells= bone marrow
Term
Humoral immunity occurs via __-cells while cell-mediated immunity occurs via __-cells.
Definition
-B-cells using antibodies
-T-cells using cytotoxic lymphocytes to kill virus infected cells and secretion of cytokines
Term
In contrast to innate immunity, adaptive immunity is (faster/slower) to respond, recognizes (individual/varied) pathogens, and (has/lacks) long-term memory.
Definition
-slower
-individual
-has
Term
Where is cowpox evident on an infected cow?
Definition
-udder and teats of cows
Term
Does cowpox only affect cows?
Definition
-NO, also affects humans and other animals, either directly or via rats
Term
Which region of an antibody (Ab) changes?
Definition
-Fab, variable region
Term
PRACTICE DRAWING AN ANTIBODY (slide 12 of L2)
Definition
Term
What is the significance of the relative size of a IgG versus a bacterium?
Definition
-IgG is so small that it can cover the entire bacterium en masse
Term
What are BCRs?
Definition
-B-cell receptors that eventually detach from the B-cell to become antibodies
-each has its own set of unique set of BCRs
Term
What do B-cells do upon activation?
Definition
-they clonally expand to make replica B0cells with same unique set of BCRs
Term
When do B-cells become plasma cells?
Definition
-when their BCRs are released as antibodies
Term
Definition: Epitope
Definition
-a stretch of 5-7 AAs on a protein that is recognized by BCRs
-generally situated on the outside of the antigen or pathogen
Term
Antibodies recognize the (outside/inside) of a pathogen with cell-mediated response senses the (outside/inside) portion.
Definition
-outside
-inside
Term
What are the functions of Ab opsonization?
Definition
-Ab bind to pathogens via their Fab region
-the exposed Fc region is recognized by Fc receptors on the surface of macrophages, neutrophils, and NK cells
-macrophages and neutrophils phagocytize the opsonized pathogen (extracellular pathogens)
-NK cells do not phagocytize pathogens, they kill then (intracellular pathogens)
Term
Describe how Ab neutralize toxins and viruses.
Definition
-Ab attach to pathogens and toxins
-this prevents them from recognizing and attaching to their receptors on cells
Term
What is the fat of B-cell clones?
Definition
-some become plasma cells while others stop proliferating and become memory B-cells
Term
What is the function of plasma cells?
Definition
-secrete Ab molecules that have the same Fab structure as that of the BCR
Term
What is the function of memory cells?
Definition
-circulate as B-cells with BCR on their surface that survive until the individual dies
-they can be reactivated if the animal is re-infected or re-vaccinated with the same pathogen
Term
How can we achieve diversity of BCR and Ab?
Definition
-they make a random choice of gene segments by recombination
Term
Compare/Contrast B-cells and T-cells
Definition
-B-cells: mature in bone marrow, have B-cell receptors (BCRs) on surface, recognize unprocessed Ags
-T-cells" mature in thymus, have T-cell receptors (TCRs) on surface, recognize only processed peptide molecules
Term
TCRs (what does this stand for?) only recognize (processed/unprocessed) peptide molecules presented by __________ molecules.
Definition
-TCR= T-cell receptors
-processed
-major histocompatibility (MHC)
Term
Once a dendritic cell has captured an Ag, what happens to it?
Definition
-takes it to the nearest lymph node, then attaches to an MHC molecule to be eaten by B-cells and T-cells
Term
True or False: Viral antigens are usually 9-14 AAs long, thus TCRs do not need an MHC to present the antigen to them.
Definition
FALSE, they do need it presented by an MHC
Term
Why can we not simply inject somebody with the epitopes that are recognized by the antibodies?
Definition
-the epitopes are dependent on antigen conformation. if we destroy the conformation, then they will no longer be the epitope, just AA fragments.
Term
What is different b/n the epitopes that are recognized by B-cells and T-cells?
Definition
-B-cells recognize surface epitopes (unprocessed)
-T-cells recognize epitopes on the inside of Ags, thus they muct be broken down and the epitopes presented by MHC molecules
Term
True or False: T-cells can only recognize an epitope when it is presented by an MHC molecule, thus forming a complex.
Definition
TRUE
Term
What occurs in an autoimmune disease?
Definition
-T-cells start to recognize our own proteins and begin the process of apoptosis
Term
What are the 3 types of T-cells?
Definition
-cytotoxic T-lymphocytes (CTL)
-helper T-cells (Th)
-regulatory T-cess (T-reg)
Term
What do CTLs do?
Definition
-cytotoxic T-lymphocytes
-kill cells if its TCRs recognize the peptide presented by an MHC I but DOES NOT KILL EXTRACELLULAR BACTERIA
Term
What are Ths?
Definition
-helper T-cells
-their TCR can only recognize a peptide presented by an MHCII molecule on antigen presenting cells (APC), then they will secrete cytokines that help B-cells produce Ab
-Th turn on immune response
Term
What to T-reg's do?
Definition
-regulatory T-cells
-they have TCR that recognize a peptide presented by MHC II but they swith OFF the immune response
Term
Why is it significant that Th cells use MHC II and cytotoxic T-cells use MHC I?
Definition
-MHC I is everywhere, while MHC II is rare, thus it is significantly more specific
Term
Definition: Endogenous
Definition
-comes from within the cell
Term
Definition: Exogenous
Definition
-comes from outside the cell (thus they have been phagocytized)
Term
MHC I molecules display small (endogenous/exogenous) peptides that are 8-10 AAs long.
Definition
-endogenous
Term
How do cytotoxic T-cells (CTLs) kill?
Definition
-they first release perforin that drills a hole in the cell
-then it injects granzyme through the hole into the cell, this causes the cell to undergo apoptosis
Term
What occurs in type I diabetes?
Definition
-an autoimmune disease where cytotoxic T-cells recognize insulin peptides on MHC molecules, thus it kills insulin-producing beta cells in the pancreas
Term
MHC II molecules are present only on the surface of cells called ___________. Examples?
Definition
-antigen presenting cells )APC)
-ex: macrophages, dendritic cells, and B-cells
Term
MHC II molecules displar only (endogenous/exogenous_ peptides derived from phagocytosis. These peptides are recognized by what?
Definition
-exogenous
-T-helper and T-reg cells
Term
All the lymph in the body drains to the ________.
Definition
-thoracic duct
Term
True or False: Anything that enters the GI and respiratory tracts encounters the MALT.
Definition
TRUE
Term
Where in the lymph node are T-cells and B-cells located?
Definition
-paracortical area
Term
What is the general purpose of germinal centers?
Definition
-to form antibodies and B-cell replication
Term
Definition: Tolerance
-what is the pass rate?
Definition
-the process by which all of our T-cells and B-cells are presented our own proteins while they are developing, testing to see if they will kill our own cells
-only 3% pass the test
Term
Pathogens will first activate the innate immune system via _____ molecules binding to PRR (inflammation).
Definition
-PAMP
Term
True or False: The innate immune system must be activated inorder for the adaptive immune response to become activated.
Definition
TRUE
Term
Between innate and adaptive immunities, which is:
a) more specific?
b) quicker?
c) has memory?
Definition
a) adaptive
b) innate (adaptive= 4-7d)
c) ONLY adaptive has memory
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