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LYMPHATIC/IMMUNE SYSTEM period 6 Karen Morales - Coggle Diagram
LYMPHATIC/IMMUNE SYSTEM
period 6 Karen Morales
lines of defense
Adaptive (specific) defense system
:Third line of defense attacks particular foreign substances (takes longer to
react than innate)
Innate (nonspecific) defense system
Second line of defense: antimicrobial proteins, phagocytes, and other cells (inhibit spread of invaders; inflammation most important mechanism)Surface barriers breached by nicks or cuts trigger the internal second line of defense that
protects deeper tissues
Macrophages: develop from monocytes and are chief phagocytic cells; most robust phagocytic cell
Inflammatory response (macrophages, mast cells, WBCs, and inflammatory chemicals) Inflammation is triggered whenever body tissues are injured
Neutrophils: most abundant phagocytes, but die fighting; become phagocytic on exposure to infectious material
Antimicrobial proteins (interferons and complement proteins)
Phagocytes: white blood cells that ingest and digest (eat) foreign invaders
Natural Killer cells:Can kill cancer and virus-infected cells before adaptive immune system is activated
Innate system uses the first and/or second lines of defense to stop attacks by pathogens (disease-causing microorganisms) :
First line of defense: external body membranes (skin and mucosae).Skin and mucous membranes produce protective chemicals that inhibit or destroy
microorganisms
Enzymes: lysozyme of saliva, respiratory mucus, and lacrimal fluid kills many
microorganisms; enzymes in stomach kill many microorganisms
Mucin: sticky mucus that lines digestive and respiratory tract traps microorganisms
Acid: acidity of skin and some mucous secretions inhibits growth; called acid mantle
Innate and adaptive defenses are intertwined.Both release and recognize many of the same defensive molecules.Innate defenses do have specific pathways for certain substances
Major functions of the Lymphatic & Immune systems
lymphatic system
maintaining body fluid levels
absorbing digestive tract fats
protecting your body from illness-causing invaders
removing cellular waste.
immune system
to recognize and neutralize harmful substances from the environment
to fight disease-causing changes in the body, such as cancer cells.
to fight disease-causing germs (pathogens) like bacteria, viruses, parasites or fungi, and to remove them from the body
Immune system is a functional system rather than organ system
Immune system provides resistance to disease
Adaptive immune system
is a specific defensive system that eliminates almost any
pathogen or abnormal cell in body
Cellular (cell-mediated) immunity
Lymphocytes act against target cell.Directly by killing infected cells.Indirectly by releasing chemicals that enhance inflammatory response; or activating other lymphocytes or macrophages
Humoral (antibody-mediated) immunity
Antibodies, produced by lymphocytes, circulate freely in body fluids. When B cell encounters target antigen, it provokes humoral immune response
ANTIGEN V ANTIBODIES
ANTIBODY
Capable of binding specifically with antigen detected by B cells
Five major classes: IgM, IgA, IgD, IgG, and IgE
are proteins secreted by plasma cells
Antibodies do not destroy antigens; they inactivate and tag them. Form antigen-antibody (immune) complexes
Defensive mechanisms used by antibodies:neutralization, Agglutination, precipatation, complement fixation
ANTIGEN
Targets of all adaptive immune responses
Self-antigens: all cells are covered with variety of proteins located on surface that are not antigenic to self
Antigens: substances that can mobilize adaptive defenses and provoke an immune response
One set of important self-proteins are group of glycoproteins called MHC proteins.Coded by genes of major histocompatibility complex (MHC) and unique to each individual.Contain groove that can hold piece of self-antigen or foreign antigen
ACTIVE V PASSIVE
PASSIVE
:Passive humoral immunity occurs when ready-made antibodies are introduced into body
Artificially acquired: injection of serum, such as gamma globulin
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
ACTIVE
:Active humoral immunity occurs when B cells encounter antigens and produce
specific antibodies against them
Artificially acquired: formed in response to
vaccine of dead or attenuated pathogens
Naturally acquired: formed in response to
actual bacterial or viral infection
disorders
Hodgkin’s disease
is an acquired immunodeficiency that causes cancer of B cells, which depresses lymph node cells and thus leads to immunodeficiency
Acquired immune deficiency syndrome (AIDS)
:Human immunodeficiency virus (HIV) cripples immune system by interfering with activity of helper T cells
Severe combined immunodeficiency (SCID) syndrome
: genetic defect with marked
deficit in B and T cells
Autoimmune disease
results when immune system loses ability to distinguish self from
foreign
Immunodeficiency
: congenital or acquired conditions that impair function or production
of immune cells or molecules
Autoimmunity:
production of autoantibodies and sensitized TC cells that destroys body tissues
Myasthenia gravis: impairs nerve-muscle connections
Multiple sclerosis: destroys white matter myelin
Graves’ disease: causes hyperthyroidism
Rheumatoid arthritis: destroys joints
Type 1 diabetes mellitus: destroys pancreatic cells
Hypersensitivities:
immune responses to perceived (otherwise harmless) threat that cause
tissue damage
Cells involved in the immune system and their functions
Adaptive immune system involves three crucial types of cells
T lymphocytes (T cells)cellular immunity:directly killing infected host cells, activating other immune cells, producing cytokines and regulating the immune response.T cells provide defense against intracellular antigens.Some T cells directly kill cells; others release chemicals that regulate immune response
CD8 cells become cytotoxic T cells (TC) that are capable of destroying cells harboring foreign antigens
CD4 cells usually become helper T cells (TH) that can activate B cells, other T cells, and macrophages; direct adaptive immune response.Some become regulatory T cells, which moderate immune response
Helper, cytotoxic, and regulatory T cells are activated T cells
T cells respond only to processed fragments of antigens displayed on surfaces of cells by major histocompatibility complex (MHC) proteins
Antigen Presenting cells:detects, engulfs, and informs the adaptive immune response about an infection. When a pathogen is detected, these APCs will phagocytose the pathogen and digest it to form many different fragments of the antigen.
Macrophages:Present antigens to T cells, which not only activates T cell, but also further activates macrophage.Activated macrophage becomes phagocytic killer
B lymphocytes:Present antigens to helper T cell to assist their own activation.
B cells are activated when antigens bind to surface receptors, cross-linking them.Triggers receptor-mediated endocytosis of cross-linked antigen-receptor complexes (clonal selection), leading to proliferation and differentiation of B cell into effector cells.Most clone cells become plasma cells, antibody-secreting effector cells.Clone cells that do not become plasma cells become memory cells
Primary immune response: cell proliferation and differentiation upon exposure to
antigen for the first time
Secondary immune response:Re-exposure to same antigen gives faster, more prolonged, more effective response
Dendritic cells :Phagocytize pathogens that enter tissues, then enter lymphatics to present antigens to T cells in lymph node
B lymphocytes (B cells)humoral immunity: produce antibodies to fight bacteria and viruses. These antibodies are Y-shaped proteins that are specific to each pathogen and are able to lock onto the surface of an invading cell and mark it for destruction by other immune cells.
Cytokines
Chemical messengers of immune system
Mediate cell development, differentiation, and responses in immune system
Helper T (TH) cells:Play central role in adaptive immune response.Activate both humoral and cellular arms.Once primed by APC presentation of antigen, helper T cells:Help activate B cells and other T cells,Induce T and B cell proliferation,Secrete cytokines that recruit other immune cells,Without TH, there is no immune response
Cytotoxic T (TC) 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.
Regulatory T (TReg) cells:Important in preventing autoimmune reactions
LYMPHATIC ORGANS
spleen: in the left rib cage. stores and filters blood and makes white blood cells that protect you from infection.
malt: initiates immune responses to specific antigens encountered along all mucosal surfaces.
thymus ( primary organ):in the chest, between the lungs and behind the breastbone. it makes white blood cells
appendix:protect good bacteria in gut
tonsils: located in the back of throat.stop germs entering the body through the mouth or the nose
red bone (primary organ):blood and immune cells are produced
lymph nodes:located inthe neck, armpits, groin, and between the lungs. they drain lymph fluid from the body.
Peters patches: in the small intestine. manage the materials within your digestive system.
