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Immune system Jessika Lee P.1 - Coggle Diagram
Immune system Jessika Lee P.1
Major functions of immune system
provides resistance to disease
made up of 2 intrinsic systems: Innate defense system, adaptive defense system
Adaptive defense system attacks foreign substances
both release and recognize many of same defensive molecules
Innate defenses have specific pathways for certain substances
innate responses release proteins that alert cells of adaptive system to foreign molecules
Location and function of lymphatic organs
primary lymphoid organs: bone marrow and thymus
create lymphocytes
bone marrow is sponge like tissue found inside of bones
creates immune system cells
thymus located behind breastbone behind above the heart
lymphocytes mature in thymus
secondary lymphoid organs: tonsils, spleen, appendix, peyer patches
lymph nodes, small bean shaped tissues found along lymphatic vessels
act as filters
cleanse lymph
spleen cleanses blood and removes aged or defective red blood cells
site for lymphocyte activation and proliferation
stores platelets, monocytes, iron
tonsils located at throat
stop germs from entering the body through mouth or nose
white blood cells, kill germs
peyer patches
appendix carries white blood cells needed to fight infections
lower right side of abdomen
antigens and antibodies
basic antibodies structure: overall T or 4 shaped antibody monomer consists of 4 looping polypeptide chains linked by disulfide bonds
2 identical heavy (H) chains with hinge region
2 identical light (L) chains
variable (V) regions at one end of each arm combine to form 2 identical antigen-binding sites
antibody classes- 5 major classes: lgM, lgA, lgP, lgG, lgE
targets and functions: do not destroy antigens; they inactivate and tag them
form antigen-antibods (immune) complexes
antibodies go after extracellular pathogens, they do not invade solid tissue unless lesion is present
antigens: substances that can mobilize adaptive defenses and provokes an immune response
targets of all adaptive immune responses
most are large, complex molecules not normally found in body
characteristics: can be complex antigen
contain antigen determinants
can be self-antigen
Self-antigens: all cells are covered with variety of proteins located on surface that are not antigens to self, may be antigenic to others in transfusions
antigen presenting cells: do not respond to specific antigens
play essential auxiliary roles in immunity
3 major types: dendritic cells, macrophage, B cells
purpose of first, second, third line of defense
second line of defense
innate system necessary if microorganisms invade deeper tissue include: phagocytes, natural killer cells, inflammatory response, antimicrobial proteins, fever
many second line cells have pattern recognition receptors that recognize an bind tightly to structures on microbes, disarming them before they do harm
third line of defense attacks particular foreign substances
first line of defense
surface barriers are skin and mucous membranes, along with their secretions
physical barrier to most microorganisms
keratin is resistant to weak acids and bases, bacterial enzymes, toxins
mucosae provide similar mechanical barriers
skin and mucous membranes produce protective chemicals that inhibit it destroy microorganisms
acid: acidity of skin and some mucous secretions inhibits growth
enzymes: lysozyme of saliva, respiratory mucus, and lacrimal fluid kills many microorganisms
mucin: sticky mucus that lines digestive and respiratory tract traps microorganisms
Major functions of lymphatic system
removes excess fluids from body tissues
produces immune cells: lymphocytes, plasma cells, monocytes
resistance to disease
deal with cancer cells
absorption of fatty acids
protect body from invaders
Innate immune defenses
constitutes first and second lines of defense
innate and adaptive intertwined
release and recognize many of same defensive molecules
do not have specific pathways for certain substances
release proteins that alert cells of adaptive system to foreign molecules
skin barriers: skin, mucous membrane
internal defenses: phagocytes, natural killer cells, inflammation, antimicrobial proteins, fever
Adaptive immune defenses
third line of defense attacks particular foreign substances
intertwined with innate
humoral immunity: B cells
cellular immunity: T cells
specific system that eliminates almost any pathogen or abdominal cell in body
specific: recognizes and targets specific antigens
systemic: not restricted to initial site
memory: mounts an even stronger attack to "known" antigens
2 main branches: humoral and cellular
Humoral: antibodies produced by lymphocytes circulate freely in body fluids
bind temperature to target cells
cellular immunity: lymphocytes act against target cell
directly by killing
humoral and cellular response
T cells provide defense against intracellular antigens
some T cells directly kill cells; others release chemicals that regulate immune response
T cells are more complex than B cells both in classification and function
humoral immune response
when B cell encounters target antigen, provokes humoral immune response
antibodies specific for that particular antigen are pronounced
antibodies produced by lymphocytes circulate freely body fluids
bind temporarily to target cells
mark for destruction
Artificial vs. naturally acquired immunity
Naturally acquired: antibodies delivered to fetus via placenta or to infant through milk
Artificially acquired: injection of serum, such as gamma globulin
Naturally acquired: formed in response to actual bacterial or viral infection
Artificially acquired: formed in response to vaccine of dead or attervated pathogens
Passive vs. active immunity
Passive humoral immunity occurs when ready made antibodies are introduced into body
b cells are not challenged by antigens; immunological memory does not occur
protection ends when antibodies degrade
Naturally acquired: antibodies delivered to fetus via placenta or to infant through milk
Artificially acquired: injection of serum, such as gamma globulin
protection immediate but ends when antibodies naturally degrade in body
Active humoral immunity occurs when B cells encounter antigens and produce specific antibodies them
2 types of active humoral immunity:
Naturally acquired: formed in response to actual bacterial or viral infection
Artificially acquired: formed in response to vaccine of dead or attervated pathogens
Disorders
pus : creamy yellow mixture of dead neutrophils tissue/cell, and living/dead
abscess: collagen fibers are laid down, walling off
sac of pus: may need to be surgically drained
autoimmunity: production of antibodies and sensitized Tc cells that destroy body tissues
Rheumatoid arthritis destroys joints
treatment- suppress entire immune system
hypersensitivities: immune responses to perceived threat can cause tissue damage
immediate hypersensitivity also called acute hypersensitivities; begin in seconds after contact with allergen
initial contact is asymptomatic but sensitizes person
immunodeficiencies: congenital or acquired conditions that impair function or production of immune cells or molecules
severe combined immunodeficiency syndrome: genetic defect with marked deficit in B and T cells
Hodgkin's disease is an acquired immunodeficiency, causes cancer of B cells, depresses lymph node cells and leads to immunodeficiency
Acquired immune deficiency syndrome, human
immunodeficiency virus cripples immune system by interfering with activity of helper T cells
sever weight loss, night sweats, swollen lymph nodes
enters body via blood transfusions, blood contained needles, intercoursce, oral sex, mother to fetus
destroys TH Cells
helper T Cells- play role in adaptive immune response
activate both humoral
help to activate B cells and other T cells
induce T cells and b cell proliferation
secrete cytokines that recruit other immune cells
without TH there is no immune response
CD4 Cells- become helper T cells
can activate B cells other T cells, and macrophages
direct adaptive immune response
some become regulatory T cells- moderate immune response
CD8 Cells become cytotoxic cells
capable of destroying cells harboring foreign antigens
memory cells
provide immunological memory
mount and immediate response to future exposures to same antigen
plasma cells, antibody secreting effector cells
secrete specific antibodies at rate of 2000 molecules per second for 4-5 days, then die
circulate in blood or lymph, binding to free antigens, marking them for destruction by innate or other adaptive mechanisms
dendritic cells - found in concrete tissues and epidermis
act as a mobile sentinels of boundary tissue
phagocyte pathogens that enter tissues then enter lymphatics to present antigens to T cells in lymph node
natural killer cells- nonphagocytic, large granular lymphocytes that police blood and lymph
can kill cancer and virus-infected cells before adaptive immune system is activated
attack cells that lack "self" cell-surface receptors
kill by inducing apoptosis in cancer cells and virus-infected cells
cytotoxic T cells
directly attack and kill other cells
activated Tc cells circulate in blood and lymph and lymphoid organs in search of body cells displaying antigen they recognize
Target virus infected cells
cells with intracellular bacteria or parasites
cancer cells
foreign cells
deliver lethal hit using 2 mechanisms
regulatory T cells - important in preventing autoimmune reactions