Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
49 Cards in this Set
- Front
- Back
|
General functions
|
aids in regulation of fluid balance
transports dietary fats participates in immune response |
|
|
Lymph
|
blood filtrate which is identical to interstitial fluid; also contains a large number of circulating lymphocytes, macrophages & dendritic cells (WBCs)
|
|
|
Lymphatic circulation
|
-lymph capillaries
-lymphatic collecting vessels -lymphatic trunks -lymphatic ducks |
|
|
Mechanism of lymphatic circulation
|
slow, sporadic flow is generated by a small pressure gradient between the tissue space & the large veins. Flow is aided by muscle contractions and one-way valves in some vessels
|
|
|
Lymphoid cells
|
lymphocytes, dendritic cells, phagocytic cells
|
|
|
Lymphoid tissue
|
serve as sites of synthesis & maturation of WBCs, & filter lymph of blood to remove pathogens & foreign particles
|
|
|
Bone Marrow
|
source of all blood cells; site of maturation for B lymphocytes
|
|
|
Thymus gland
|
site of maturation of T lymphocytes
|
|
|
Lymph nodes
|
contain high density of lymphoid cells; serve as site for exposing these cells to pathogens circulating in lymph
|
|
|
Spleen
|
contains high density of lymphoid cells; serves as site for exposing these cells to pathogens in the blood
|
|
|
Tonsils
|
contain high density of lymphoid cells; serve as sites for exposing these cells to pathogens that enter the body through mucus membrane in respiratory tract
|
|
|
Diffuse lymphatic tissue
|
distributed throughout respiratory & digestive tract
|
|
|
Resistance to disease
|
immunity
|
|
|
Infection
|
condition caused by presence & multiplication of pathogens
|
|
|
Nonspecific (Innate) immunity
|
general defense mechanism, independent of pathogen type
|
|
|
Specific (adaptive) immunity
|
defense directed at particular pathogens
|
|
|
Mechanical barriers (NS)
|
skin, mucous membranes, ciliated epithelium
|
|
|
Chemical protection (NS)
|
sebaceous glands in skin; enzymes in perspiration/tears; gastric secretions; vaginal secretions
|
|
|
Antimicrobial substances (NS)
|
interferons: proteins produced by lymphocytes & fibroblasts, inhibit viral production stimulate phagocytosis
|
|
|
Phagocytosis (NS)
|
destruction of foreign substances by engulfing & digesting (endocytosis).
-Phagocytic cells: neutrophils phagocytize small particles; macrophages( develop from monocytes) phagocytize larger particles; tissue specific macrophages remain within an organ |
|
|
Natural Killer Cells (NS)
|
a type of lymphocyte with some innate (in built) ability to destroy virus infected & cancer cells; nonspecific, not phagocytic
|
|
|
C-Reactive Protein (NS)
|
produced by liver in response to chemicals released during inflammation; function to bind to & mark pathogens for destruction by phagocytes or complement
|
|
|
Complement (NS)
|
plasma proteins that act nonspecifically under some circumstances to cause cell lysis (more important in specific immune response)
|
|
|
Fever (NS)
|
due to endogenous pyrogens; low grade fevers may enhance immune system function
|
|
|
Inflammation
|
tissue response to injury that aids in healing & defense against pathogens, changes that produce inflammation are initiated by chemical mediators
|
|
|
Changes include ( inflammation):
|
-vasodilation
-increased capillary permeability -activation of pain receptors -attraction of WBCs |
|
|
Cells (S)`
|
-T lymphocytes
-B lymphocytes -Macrophages & accessory cells |
|
|
Antigens (ANTIbody GENerating)
|
large, complex molecules with antigenic determinants to provoke immune responses; lymphocyte receptor can bind to it
|
|
|
Types of compounds that are antigenic
|
-proteins
-glycoproteins -lipoproteins -some nucleic acids -some polysaccharides |
|
|
Self Tolerance
|
appropriate specific immunity requires that cells which belong to the body are tolerated by B & T lymphocytes- their receptors can't bind strongly to them
|
|
|
Major histocompatibility proteins (MHC)
|
family of glycoproteins which are expressed on all nucleated cells. They are genetically determined; their expression is unique in all individuals (except identical twins). Tissue typing for transplantation involves finding tissues with similar MHCs.
|
|
|
What are used to screen lymphocytes against "self"?
|
MHCs & other "self" antigens.
All lymphocytes which have receptors that strongly bind to "self" antigens must be destroyed in the screening process, or autoimmunity (reaction with self) will result. |
|
|
Screening B lymphocytes occurs in what?
|
bone marrow
|
|
|
Screening T lymphocytes occurs in what?
|
thymus
|
|
|
After screening of these cells (B & T lymphocytes) what happens?
|
these cells are immunocompetent and self tolerant.
Specific immunity becomes effective (is acquired) via exposure to a pathogen (via environmental exposure, or vaccination) |
|
|
Activation:
|
binding of these specific receptors to their antigenic determinant results in an increase in the number of cells that express the same receptor; also results in formation of "memory" cells that have the ability to react more effectively on subsequent exposures to the antigen
|
|
|
Antibody mediated (type of specific immun.)
|
indirect attack on antigens by antibodies (large immunoglobulins) circulating in body fluids (called "humoral" immunity to refer to blood and lymph fluids); B lymphocytes make antibodies; most effective against bacteria & their toxins. Also aids in removal of viruses from body fluids
|
|
|
Cell mediated immunity
|
involves direct binding & chemical attack on cells by T lymphocytes; very important as defense against viruses, intracellular bacteria, parasites & fungi, virally infected cells (pathogens with "hide")
|
|
|
Activation of B lymphocytes
|
a "naive" B cell encounters an antigen
Stimulas: Naive B cell binds to antigenic determinant (pathogen) in body fluids Response: increase in number of B cells (mitosis) with same receptor as that bound to antigen ("clonal selection"). Some B cells differentiate into plasma cells, which secrete antibodies. Memory cell form & retain the ability to make antibodies next time against the same antigen (increased effectiveness during subsequent exposure- save time!) |
|
|
Antibodies
|
group of globular proteins: immuniglobulins, gamma globulins
Antibodies are formed from Y-shaped monomers that have 2 sites to bind to antigenic determinants on the arms of the Y. The region of the molecule making up the base is similar in all antibodies : binding site for macrophages, binding site for complement protein. |
|
|
General classifications IgG:
|
about 80% of the antibody secreted; secreted as a monomer
|
|
|
IgD
|
acts as antigen receptor on lymphocyte membrane
|
|
|
IgM
|
acts as antigen receptor on lymphocyte membrane (monomer) & is the 1st antibody secreted during a primary response (secreted as a pentamer)
|
|
|
IgA
|
found in body fluids: saliva, sweat, milk (monomer & dimer)
|
|
|
IgE
|
attaches to basophils & mast cells ; associated with allergic reactions
|
|
|
Antibody function
|
bind to antigens to prepare them for destruction
-neutralize, agglutinate & precipitate antigens -stimulate phagocytosis (opsonization) -activate complement proteins |
|
|
Complement proteins
|
are a group of >20 plasma proteins circulating in an active form
The activation of complement leads to a cascade of reactions that result in the construction of a large pore in the membrane of a pathogen- the cell lyses open, and the threat is averted. It also amplified inflammation and promotes phagocytosis |
|
|
The most common mechanism ("classical pathway") for complement activation
|
by binding of antibody to antigens on the pathogen
1. Recognition: three complement proteins bind with the antigen-antibody complex 2. Activation: binding of the complement proteins lead to activation of a key complement protein which catalyzes the combination of several other complement proteins 3.Attack: insertion of complement proteins in the cell membrane of the pathogen and formation of membrane attack complex (MAC) as a large pore in the pathogen's cell membrane. This leads to lysis of the pathogen. |
|
|
Primary & Secondary B-Lymphocyte Responses
|
Memory cells are formed during initial exposure; these increase the efficiency of the secondary response because the antibody concentration rises more quickly & to a much higher concentration, when compared with primary response
|
