The ImmuneSystemT- 1-855-694-8886Email- info@iTutor.comBy iTutor.com
Objective The role of the skin Roles of anti-bodies Phagocytes B-lymphocytes T-lymphocytes Role of vaccines Bacterial and viral infections
The Immune System The immune system is the body‟s natural defense againstdisease-causing agents such as bacteria, viruses and parasites. The immune system is made up of a complex and vital networkof cells and organs that protect the body from infection. It plays an important role in identifying and eliminatingabnormal cells. The Human Immune System is divided into two broadgroups : Acquired Immune SystemAlways working to protect the body and does not require anyspecial preparation to stop infection. Innate Immune SystemNeeds to be primed before it can work to its full effectivenessthough, and is only really effective after it has seen a possibleinfective agent before.
The Immune SystemInnate Immunity Acquired ImmunityB-Cell Immunity T-Cell Immunity Resistance of skin Destruction oforganisms by theacids in the stomach Chemicalcompounds in theblood Cells called„Macrophages‟ thatingest foreignobjects Consist of B-cells Produce Anti-Bodies Involved withPrimary andSecondaryresponse Consists of T-Cells T-Cells are: T helper cells T killer cells
Structure and organs of the Immune System The structures of the immune system, detailing the parts ofthe body that play a role in immunity. These include:– The lymphatics– Lymph nodesLymphatic Organs and Structures– Thymus– Spleen Lymph– A fluid containing: Water Sugars Salts Waste White Blood Cells Protein Lymph Vessels– Carry lymph within thelymphatic system– Lymph capillaries arethe smallest of thelymph vessels
The ImmunesystemAdenoidsTonsilsThymusSpleenPayer’s PatchesBonemarrowLymph NodesLymphatic VesselsAppendix
Capillaries Capillaries have thin walls which allow fluid in bodytissues to flow between the capillaries and tissues.7Fluid in the spacesbetween tissues is calledinterstitial fluidOnce the interstitialfluid flows into thelymph capillaries it iscalled lymphLymphatic trunkRight lymphatic duct orthoracic ductRight subclavianvein (neck)Lymphatic vesselLymphatic capillaryInterstitial fluidBlood streamStructure and organs of the ImmuneSystem
Lymphatic VesselsPulmonary capillarynetworkBlood flowSystemic capillarynetworkLymphaticcapillariesLymphnodeLymphaticvesselsLymphflowLymphnodeLymphflowLymphaticcapillariesStructure and organs of the ImmuneSystem
Lymph Nodes Specialized organs that produce lymphocytes. Filter harmful substances from the tissues. Contain macrophages that devour foreign substances. Lymphocytes produce specialized proteins called antibodies that fightdisease. Antigens also fight disease by stimulating an immune response inother cells.9Structure and organs of the ImmuneSystemLymph Travels in only one direction. Empties into the right thoracic duct and the lymphatic duct. Lipids are transported from the small intestines to the blood streamby the lymph vessels.Location of major groups of lymph nodes:- Tonsils -Mediastinum-Groin-Neck-Adenoids -Armpit
Spleen Largest lymphatic organ located in upper left portion of the abdominalcavity. Filters foreign material from the blood. Destroys old red blood cells Activates lymphocytesStructure and organs of the ImmuneSystemThymus Gland Soft gland with two lobes Larger during infancy and childhood Contains important cells called thymocytes T cells (T lymphocytes provide immunity) Thymosin aids with T cell movement
Major PlayersThe major players in the immune system include:– Macrophage– T cells (helper, cytotoxic, memory)– B cells (plasma, memory)– AntibodiesWhite Blood Cells – LymphocytesThe lymphocytes are of 2 types• T lymphocytes• B lymphocytes Higher rank officials of the immune system and have a sophisticatedmode of action. Their importance is highlighted by the fact, that an absence oflymphocytes, which occurs in AIDS, leaves the body unprotectedfrom infections and finally leads to early death.
B- lymphocytes The B lymphocytes are present in lymph nodes. Upon finding the relevant antigens get activated and transformthemselves to plasma cells. Plasma cells secrete large quantities of antibodiescorresponding to the antigen found by the B lymphocytes. These antibodies circulate in blood and attach to all infectingorganisms and cells present in the body having the concernedantigen.T- lymphocytes This helps them recognize all the tissues of one‟s own body. Their response to an overwhelming infection, is in the form ofmultiplication of the particular cell family concerned withdestruction of the particular foreign antigen. They not only destroy the antibody coated cells but also stimulateactivation and formation of plasma cells by B lymphocytes. The T lymphocytes are highly specialized and trained cells, whichintelligently tackle infections by recognizing and multiplication of aspecific lineage of cells, which perform higher immune functions.
AntibodiesAntibodies areassembled out ofprotein chains.There are manydifferent chains thatthe immune systemassembles in differentways to make differentantibodies.
Antibodies as ReceptorsAntibodies canattach to Bcells, and serve torecognize foreignantigens.
Antigens as Effectors• Free antibodies canbind toantigens, which“tags” the antigen forthe immune systemto attack and destroy.
Role of antibodies Antibodies released into theblood stream will bind to theantigens that they are specificfor. Antibodies may disable somemicrobes, or cause them to sticktogether (agglutinate). They “tag” microbes so that themicrobes are quickly recognizedby various white blood cells.
Role of SkinDead skin cells areconstantly sloughedoff, making it hard forinvading bacteria tocolonize.Sweat and oils containanti-microbialchemicals, includingsome antibiotics.
Role of mucus and ciliaMucus contains lysozymes,enzymes that destroybacterial cell walls.The normal flow of mucuswashes bacteria and virusesoff of mucus membranes.Cilia in the respiratory tractmove mucus out of the lungsto keep bacteria and virusesout.Nasalmucosa
Role of phagocytesPhagocytes are several typesof white blood cells (includingmacrophages and neutrophils)that seek and destroyinvaders. Some also destroydamaged body cells.Phagocytes are attracted by aninflammatory response ofdamaged cells.
The not-so-common cold A “cold” is an infectionof the mucusmembranes of therespiratory tract by arhinovirus. Over 100 rhinoviruseshave beenidentified, which is onereason why we don‟tbecome immune to “thecold.”
Virus vs. BacteriaColds and influenza arecaused by viruses.Viruses are which is anon-living particle thatcontains geneticmaterial, and hijacksyour cells to reproduce.Viruses cannot be“killed” withantibiotics.RhinovirusInfluenzavirus
Virus vs. BacteriaBacteria are livingorganisms that have ametabolism, haveDNA, and can reproduceon their own.Bacteria can be killedwith antibiotics becausethese substances targetkey processes inbacteria, such asproduction of thebacterial cell wall.E. coliStreptococcus
Helping the Immune SystemMedical science hascreated to systems foraugmenting the humanimmune system:– Antibiotics– Vaccines
How antibiotics workAntibiotics help destroy bacteria (but not viruses).Antibiotics work in one of several ways:– Slowing bacteria reproduction.– Interfering with bacterial cell wall formation.
How vaccines workModern vaccines are created from killed bacteria orviruses, or fragments of proteins from thesemicrobes.The proteins are recognized as antigens by ourimmune systems. This causes a mild immuneresponse. Memory T-cells and B-cells remain readyto fight off the illness if it is encountered again.
AIDSAIDS (Acquired Immune Deficiency Syndrome)is caused by an infection by the HIV (HumanImmunodeficiency Virus), which attacks anddestroys T-helper cells. Because it attacks theimmune system directly, finding a vaccine hasbeen difficult.Some drugs can slow down HIVreproduction, but no cure exists yet. Preventionis still the best “cure.”
AIDSThe HIV virus fools helper T-cells intothinking its proteins are “self,” and sois able to infect the cells that triggerspecific immunity.The virus forces T-cells tomake more viruses, killing theT-cells when the new virusesburst out.
AIDS PreventionHIV is a fragile virus that cannot live outside thehuman body for more than a few minutes.Preventing HIV spread comes down to preventingexposure to body fluids of an infected person.
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