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Immune System McKenzie Nazionale Period 1 - Coggle Diagram
Immune System
McKenzie Nazionale
Period 1
major functions of the Lymphatic and Immune Systems
lymphatic
maintains fluid levels in our body tissues by removing all fluids that leak out of our blood vessels
immune
protect you from foreign invaders (bacteria, viruses, parasites, and fungi) that cause infection, illness and disease
Location of Lymphatic organs and their Functions
Lymph nodes
site for lymphocyte activation and proliferation
cleanse lymph
spleen
cleanse blood and removes defective RBC
lymphocyte activation proliferation
stores platelets, monocytes, and iron
MALT (mucosa associated lymphoid tissues)
prevent pathogens from penetrating mucous membrane
lymphocyte activation and proliferation
Thymus
site for T vell maturation
Purpose and examples of First, Second and Third Line of defense
First Line of Defense
skin and mucous membranes with secretions
skin and mucous membranes produce protective chemicals to inhibit or destroy microorganisms
acid: acidity of skin and some mucous secretions inhibit growth
enzymes: lysozome of saliva, respiratory mucus, and lacrimal fluid kills many microorganisms;enzymes in stomach
mucin: sticky mucus that lines digestive and respiratory tract traps microorganisms
respiratory system has modifications stopping pathogens
surface barriers breached by cuts trigger the internal 2nd line of defense protecting deeper tissues
Second Line of Defense
necessary if microorganism invades deeper tissues
phagocytes
phagocytes: WBCs that ingest and digest foreign invaders
macrophages: develop from monocytes and are chief phagocytic cells; most robust phagocytic cell
neutrophils: most abundant, die fighting, become phagocytic on exposure to infectious material
natural killer cells
nonphagocytic, large granular lymphocytes that police blood and lymph
attack cells lacking "self" cell-surface receptors
kill by inducing apoptosis in cancer cells and virus infected cells
secrete potent chemicals that enhance inflammatory response
inflammatory response
inflammation is triggered when body tissues are injured
4 cardinals signs of acute inflammation
redness
heat
swelling
pain
stages of inflammation
infalmmatory chemical release
vasodilation and increased vascular permeability
phagocyte mobilization
antimicrobial proteins
fever
many second line cells have pattern recognition receptors recognizing and binding tightly to structures on microbes disarming before harm
Innate(natural) immune defenses and Adaptive(acquired) immune defenses
innate immune defense system
constitutes first and second lines of defense
2nd line: antimicrobial proteins, phagocytes, and other cells (inhibit invader spreads, inflammation)
1st line: external body membranes (skin and mucosae)
stop attacks by pathogens
adaptive immune defense system
3rd line of defense attacks foreign substances (longer to react)
eliminates almost any pathogen or abnormal cell in body
2 main branches
cellular (cell-mediated) immunity
humoral (antibody-mediated) immunity
Humoral Response and Cellular Response
Humoral
antibodies, lymphocytes, circulate freely in body fluids
bind temporarily to target cell and mark for destruction
when B cells encounter target antigen, it provokes humoral immune response; then antibodies specific for particular antigen are produced
active humoral immunity occurs when B cells encounter antigens and produce specific antibodies against them
naturally acquired: formed in response to actual bacterial or viral infection
artifically acquired: formed in response to vaccine of dead or attenuated pathogens
passive humoral immunity occurs when ready-made antibodies are introduced into the body
Cellular
lymphocytes act against target cell
indirectly release chemicals to enhance inflammaotry response; or activate other lymphocytes or macrophages
directly kill infected cells
T cells provide defense against intracellular antigens
some T cells directly kill cells; others release chemicals to regulate response
Antigens and Antibodes
antigens: substances that can mobilize adaptive defenses and provoke immune responses
targets of all adaptive immune responses
mots are large, complex molecules not normally found in body
characteristices
can be a complete antigen or hapten(incomplete)
contain antigenetic determinants
can be a self-antigen
all cells are covered with variety of proteins located on surface that are not antigentic to self, but may be to others in transfusions or grafts
one set of important self-proteins are group of glycoproteins called MHC protieins
antigen presenting cells
do not respond to specific antigens
play essential auxiliary roles in immunity
antibodies: proteins secreted by plasma cells
5 classes: IgM, IgA, IgD, IgG, IgE
targets and functions
complement fixation
main antibody defense against bacteria/mismatched RBCs
multiple antibodies on same antigen->complement-binding sites are alligned
precipitation
soluble molecules are cross-linked into complexes
complexes precipitate out of solution
precipitated complexes are easier for phaocytes to engulf
agglutination
allows antigen-antibody complexes to become cross-linked into large lattice-like clumps
neutralization
antibodies block specific sites on viruses/bacterial exotoxins
prevent antigens from binding to tissue cell receptors
simplest and most important
antigen-antibody complexes undergo phagocytosis
Artificial vs. Naturally acquired Immunity
Passive Humoral
naturally acquired: antibodies delivered to fetus via placenta to infant through milk
artificially acquired: injection of serum, gamma globulin
Active Humoral
artificially acquired: formed in response to vaccine of dead or attenuated pathogens
naturally acquired: formied in response to actual bacterial or viral infection
Passive vs. Active Immunity
Active Humoral Immunity: occurs when B cells encounter antigens and produce specific antibodies against them
Passive Humoral Immunity: occurs when ready-made antibodies are introduced to the body
Cells involved in the immune system and their functions
lymphocytes
5 general steps
seeding secondary lymphoid organs and circulation
antigen encounter and activation
maturation: lymphocytes are educated in 2-3 day process and mature in primary lymphoid organs
proliferation and differentiation
origin: both T and B cells originate in red bone marrow
antigen receptor diversity
genes determine which foreign substances the immune system will recognize
huge variety of receptors are gene segments are shuffled around resulting in many combination
antigen presenting cells
dendritic cells
found in connective tissue and epidermis
phagocytize pathogens enter tissue, enter lymphates to present antigens to T cells in lymph nodes
macrophages
widely distributed in connective tissues and lymphoid organs
present antigen to T cells, further activates macrophage
B cells
don't activate naive T cells
present antigens to helpt T cells to assist own activation
B cells
activated when antigens bind to surface receptors cross-linking
most clone cells become plasma cells, antibody-secreting effector cells
triggers receptor-mediated endocytes of cross-linked antigen-receptor complexes, leading to proliferation and differentiation of Bcells into effector cells
clone cells that don't become plasma cells become memory cells
T cells are more complex than B cells in calssification and function
CD4 cells become helper T cells that can activate B cells, T cells, and macrophages; direct adaptive immune response
CD8 cells become cytotoxic T cells that are capable of destroying cells harboring foreign antigens
helper, cytotoxic, and regulatory T cells are activated T cells
naive T cells are simply termed CD4 and CD8 cells
disorders associated with the immune system
pus: creamy yellow mixture of dead neutrophils, tissue/cells, and living/dead pathogens
immunodeficiency: congental/acquired conditions impairing function or production of immune cells or molecules
severe immunodeficiency syndrome (SCID): genetic defect with marked deficit in B and T cells
Hodgkin'sdisease: acquired immunodeficiency causing cancer of B cells which depresses lymph node cells and thus leads to immunodeficiency
autoimmune disease: results when immune system loses ability to distinguish self from foreign
Acquired immune deficiency syndrome (AIDS): human immunodeficiency virus (HIV): cripples immune system by interfering with activity of helper T cells
autoimmunity: production of autoantibodies and sensitized Tc that destroys body tissues
hypersensitivities: immune responses to perceived threat that cause tissue damage
acute (type 1) hypersensitivities begin in seconds after contact with allergen, antigen causing allergic reaction