lymphatic system chapter 12. introduction components components lymph is the fluid vessels –...
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Lymphatic Lymphatic SystemSystem
Chapter 12Chapter 12
IntroductionIntroduction ComponentsComponents
LymphLymph is the fluid is the fluid
Vessels – Vessels – lymphaticslymphatics
Structures & organsStructures & organs FunctionsFunctions
Return tissue fluid to the bloodstreamReturn tissue fluid to the bloodstream
Transport fats from the digestive tract to the Transport fats from the digestive tract to the bloodstreambloodstream
Surveillance & defenseSurveillance & defense
The Lymphatic SystemThe Lymphatic System
LymphaticsLymphatics Originate as lymph capillariesOriginate as lymph capillaries Capillaries unite to form larger vesselsCapillaries unite to form larger vessels
Resemble veins in structureResemble veins in structure
Connect to lymph nodes at various intervalsConnect to lymph nodes at various intervals Lymphatics ultimately deliver lymph into 2 Lymphatics ultimately deliver lymph into 2
main channelsmain channelsEmpty into large veins just before they join the Empty into large veins just before they join the superior vena cavasuperior vena cava
Lymph CapillariesLymph Capillaries
Lymphatic VesselsLymphatic Vessels
Main Channels of LymphaticsMain Channels of Lymphatics
Major Lymphatic Vessels of the Major Lymphatic Vessels of the TrunkTrunk
Lymph TissueLymph Tissue 3 types3 types
Diffuse lymphatic tissueDiffuse lymphatic tissue
Lymphatic nodulesLymphatic nodules Some are found singlySome are found singly Some are found in clusters in specific areasSome are found in clusters in specific areas
Eg. Tonsils; appendixEg. Tonsils; appendix
Lymphatic organsLymphatic organs
Lymph NodulesLymph Nodules
Lymph NodesLymph Nodes Oval structures located along lymphaticsOval structures located along lymphatics Enclosed by a fibrous capsuleEnclosed by a fibrous capsule Divided into compartmentsDivided into compartments
SinusesSinuses Produce lymphocytesProduce lymphocytes Lymph enters nodes through afferent Lymph enters nodes through afferent
lymphatics, flows through sinuses, exits lymphatics, flows through sinuses, exits through efferent lymphaticthrough efferent lymphatic
Lymph NodeLymph Node
TonsilsTonsils Multiple groups of large lymphatic nodulesMultiple groups of large lymphatic nodules Location – mucous membrane of the oral and Location – mucous membrane of the oral and
pharyngeal cavitiespharyngeal cavities Palatine tonsils Palatine tonsils
Posterior-lateral walls of the oropharynxPosterior-lateral walls of the oropharynx Pharyngeal tonsilPharyngeal tonsil
Posterior wall of nasopharynxPosterior wall of nasopharynx Lingual tonsilsLingual tonsils
Base of tongueBase of tongue
TonsilsTonsils
SpleenSpleen Largest lymphatic organLargest lymphatic organ Located between the stomach & diaphragmLocated between the stomach & diaphragm Structure is similar to a nodeStructure is similar to a node
Capsule presentCapsule presentButBut no afferent vessels or sinuses no afferent vessels or sinuses
ContainsContainsLymphatic tissueLymphatic tissueRed blood cellsRed blood cellsLymphocytes (plasma cells)Lymphocytes (plasma cells)Other leucocytesOther leucocytes
FunctionsFunctionsFilters bloodFilters bloodStores bloodStores blood
SpleenSpleen
Thymus GlandThymus Gland Location – behind the sternumLocation – behind the sternum The capsule divides it into 2 lobesThe capsule divides it into 2 lobes DevelopmentDevelopment
Infant – conspicuousInfant – conspicuous
Puberty – maximum sizePuberty – maximum size
Maturity – decreases in sizeMaturity – decreases in size FunctionFunction
Differentiation and maturation of T cellsDifferentiation and maturation of T cells
Thymus GlandThymus Gland
Function of the Lymphatic Function of the Lymphatic SystemSystem
Defense against harmful organisms Defense against harmful organisms and chemicalsand chemicals Nonspecific resistanceNonspecific resistance
InheritedInheritedWide variety of body reactions against a Wide variety of body reactions against a wide range of pathogenswide range of pathogens
Specific resistanceSpecific resistance Resistance to a specific disease-causing Resistance to a specific disease-causing
microorganismmicroorganism
Nonspecific ResistanceNonspecific Resistance SkinSkin
11stst line of defense line of defense Mechanical and chemical factors that fight diseaseMechanical and chemical factors that fight disease
TearsTears SalivaSaliva Flow of urineFlow of urine Gastric juiceGastric juice
Nonspecific Resistance Nonspecific Resistance (cont’d)(cont’d)
Interferon (IFN)Interferon (IFN)Produced by body cells infected with virusesProduced by body cells infected with viruses
Then released by the infected cellsThen released by the infected cells Inhibits viral replication in neighboring cellsInhibits viral replication in neighboring cells
Decreases disease-producing power of many Decreases disease-producing power of many virusesviruses
PhagocytosisPhagocytosis Inflammation Inflammation Fever Fever
Specific Resistance = ImmunitySpecific Resistance = Immunity
Involves the production of a specific cell or Involves the production of a specific cell or molecule (antibody) to destroy a specific molecule (antibody) to destroy a specific disease-causing organism or its toxin disease-causing organism or its toxin (antigen).(antigen).
Innate ImmunityInnate Immunity Inborn immunityInborn immunity Acquired ImmunityAcquired Immunity
Immunity acquired during organisms’ lifetimeImmunity acquired during organisms’ lifetime
Characteristics of the Immune Characteristics of the Immune ResponseResponse
Specificity Specificity Involves the production of a specific cell or antibody to Involves the production of a specific cell or antibody to
destroy a particular antigendestroy a particular antigen
MemoryMemoryAcquired ability to detect and eliminate foreign Acquired ability to detect and eliminate foreign substancessubstances Self vs. non-self recognitionSelf vs. non-self recognition
MHCMHC
Involves antibody-mediated and cell-mediated Involves antibody-mediated and cell-mediated immunityimmunity
Lymphocytes Initiate the Lymphocytes Initiate the Immune ResponseImmune Response
Types of lymphocytesTypes of lymphocytesT cellsT cells
80% of circulating lymphocytes80% of circulating lymphocytes
B cellsB cells 10 – 15% of circulating lymphocytes10 – 15% of circulating lymphocytes
NK cellsNK cells 5 – 10% of circulating lymphocytes5 – 10% of circulating lymphocytes
Derivation and Distribution of Derivation and Distribution of LymphocytesLymphocytes
Distribution and Life Span of Distribution and Life Span of LymphocytesLymphocytes
Ratio of B cells to T cells variesRatio of B cells to T cells varies Depends on the tissue or organ consideredDepends on the tissue or organ considered Lymphocytes continually move throughout the Lymphocytes continually move throughout the
body (wanderers)body (wanderers)
Lymphocytes have relatively long life Lymphocytes have relatively long life spansspans
Lymphocytes and the Immune Lymphocytes and the Immune ResponseResponse
2 components2 components Cell-mediated immunityCell-mediated immunity
Direct attack by T cellsDirect attack by T cells Virus & bacterial infected host cells, fungi, parasites, Virus & bacterial infected host cells, fungi, parasites,
transplanted tissues, tumors, etc.transplanted tissues, tumors, etc.
Antibody-mediated immunityAntibody-mediated immunityAttack by circulating antibodiesAttack by circulating antibodies
Released by plasma cells derived from activated B Released by plasma cells derived from activated B lymphocyteslymphocytes
Lymphocytes and the Lymphocytes and the Immune ResponseImmune Response
What is an antigen?What is an antigen?
Antigen = “Antigen = “antiantibody body gengenerating” molecule erating” molecule any chemical substance that, when introduced into any chemical substance that, when introduced into
the body, causes the body to produce specific the body, causes the body to produce specific antibodies that can react with the antigenantibodies that can react with the antigen
Properties of antigens:Properties of antigens: ForeignForeign proteins or polysaccharides proteins or polysaccharides
Examples:Examples: Cell membranes, flagella, viruses, toxins, enzymes, Cell membranes, flagella, viruses, toxins, enzymes,
pollen, transplanted tissues & organs, markers on red pollen, transplanted tissues & organs, markers on red blood cellsblood cells
Cell-mediated ImmunityCell-mediated Immunity
Characteristics of the Cell Characteristics of the Cell Mediated Immune SystemMediated Immune System
Upon interaction with specific antigens, specific Upon interaction with specific antigens, specific T cells produce T cells produce cytokinescytokines Proteins that activate both B & T cellsProteins that activate both B & T cells
Do not secrete antibodiesDo not secrete antibodies
Found in lymphoid tissue (nodes, blood, spleen) Found in lymphoid tissue (nodes, blood, spleen)
Act primarily on intracellular parasites (viruses, Act primarily on intracellular parasites (viruses, some bacteria), fungi & worms, cancer cells & some bacteria), fungi & worms, cancer cells & transplanted tissuestransplanted tissues
T Cells and ImmunityT Cells and Immunity 1000s of different types of T cells1000s of different types of T cells When an antigen enters the body, only the particular When an antigen enters the body, only the particular
T cell programmed to react with the antigen becomes T cell programmed to react with the antigen becomes activatedactivated
MacrophagesMacrophages phagocytize the antigen phagocytize the antigenMacrophages present it to the T cellMacrophages present it to the T cell
T cells increase in size, divide, differentiateT cells increase in size, divide, differentiateCytotoxic T cellsCytotoxic T cellsHelper T cellsHelper T cellsMemory T cellsMemory T cellsDelayed hypersensitivity T cellsDelayed hypersensitivity T cellsSuppressor T cellsSuppressor T cells
Duality of the Immune System
Cytotoxic T Cells (TCytotoxic T Cells (TCC) )
Migrate to the site of invasionMigrate to the site of invasionAttach to the invading cellAttach to the invading cell
Secrete substances that lyse the infected cell.Secrete substances that lyse the infected cell.
Secrete interferonSecrete interferon
A TA TCC Cell Lyses an Infected Cell Cell Lyses an Infected Cell
Helper T Cells (THelper T Cells (THH Cells) Cells)Assist in the regulation and coordination of he Assist in the regulation and coordination of he immune responseimmune responseSteps of regulationSteps of regulation 1. Processing1. Processing
Macrophage phagocytizes antigen, presents it on its surfaceMacrophage phagocytizes antigen, presents it on its surface 2. Recognition2. Recognition
Appropriate TAppropriate THH cell binds to the macrophage cell binds to the macrophage 3. Stimulation3. Stimulation
Macrophage stimulates TMacrophage stimulates TH H cell to form a clone of Tcell to form a clone of THH cells cells
Cloned cells produce cytokinesCloned cells produce cytokines Stimulate B cells and TStimulate B cells and TCC cells cells
4. Response4. ResponseTTCC cells kill infected cells, B cells produce antibodies cells kill infected cells, B cells produce antibodies
The Role of Helper T Cells as The Role of Helper T Cells as Mediators of Immune ResponsesMediators of Immune Responses
Memory T CellsMemory T Cells Recognize original invading Recognize original invading
organism if the pathogen invades organism if the pathogen invades laterlater
Swifter reaction than during the 1Swifter reaction than during the 1stst invasioninvasion
Pathogen is usually destroyed before Pathogen is usually destroyed before any symptoms appearany symptoms appear
Other T CellsOther T Cells Delayed hypersensitivity T cells (TDelayed hypersensitivity T cells (TDD))
Key factor in allergy responses and transplant Key factor in allergy responses and transplant tissue rejectiontissue rejection
Suppressor T cells (TSuppressor T cells (TSS))
Turn off the immune responseTurn off the immune response
Additional Cell ComponentsAdditional Cell Components
MacrophagesMacrophages Present antigen to TPresent antigen to THH cells, eliminate viral & cells, eliminate viral &
bacterial infected cells, attack cancer cells, bacterial infected cells, attack cancer cells, activated by antigen and cytokines from Tactivated by antigen and cytokines from THH cellscells
Natural Killer CellsNatural Killer Cells Attack and lyse foreign cells, normal cells Attack and lyse foreign cells, normal cells
infected with viruses, and cancer cells infected with viruses, and cancer cells Non-specific in actionNon-specific in action
Antibody-Mediated Antibody-Mediated ImmunityImmunity
B CellsB Cells 1000s of different kinds of B cells1000s of different kinds of B cells
Each type responds to a specific antigenEach type responds to a specific antigen When an antigen enters the bloodWhen an antigen enters the blood
B cells are activatedB cells are activated Become plasma cellsBecome plasma cells Circulate in blood and lymph to reach site of Circulate in blood and lymph to reach site of
invasioninvasion
B cells become memory B cellsB cells become memory B cells Respond more rapidly and forcefully should a Respond more rapidly and forcefully should a
22ndnd invasion occur invasion occur
What does an antigen do?What does an antigen do?
Antigen with its antigenic determinant stimulates Antigen with its antigenic determinant stimulates the formation of specific antibodies the formation of specific antibodies
The antigenic determinant, a portion of the The antigenic determinant, a portion of the antigen, reacts with an antibody to form an antigen, reacts with an antibody to form an antigen-antibody complexantigen-antibody complex
The formation of the antigen-antibody complex The formation of the antigen-antibody complex ultimately leads to inactivation and removal of ultimately leads to inactivation and removal of the antigenthe antigen
Antigenic Determinants on an Antigenic Determinants on an AntigenAntigen
What is an antibody?What is an antibody?
Large ProteinsLarge Proteins
Basic subunit has minimum of two binding sites Basic subunit has minimum of two binding sites at which it combines with antigensat which it combines with antigens Also known as “immunoglobulins”Also known as “immunoglobulins”
Antibody ConfigurationAntibody Configuration
2 Methods of Antibody 2 Methods of Antibody ProductionProduction
T cell independent productionT cell independent production B cells differentiate without the interaction of B cells differentiate without the interaction of
TTHH cells cells
T cell dependent productionT cell dependent production B cells differentiate with the interaction of TB cells differentiate with the interaction of THH
cellscells
T cell Independent AntigensT cell Independent Antigens
T cell Dependent Antigens & T cell Dependent Antigens & Antibody ProductionAntibody Production
Outcome of Antibody Outcome of Antibody Production by B cellsProduction by B cells
Disorders of the Immune Disorders of the Immune SystemSystem
AllergyAllergyPerson is overly reactive to an antigenPerson is overly reactive to an antigen
Autoimmune diseasesAutoimmune diseasesBody has difficulty in discriminating between its own antigens Body has difficulty in discriminating between its own antigens and foreign antigensand foreign antigens
Severe Combined Immunodeficiency (SCID) Severe Combined Immunodeficiency (SCID) Both T cells and B cells are absent or inactiveBoth T cells and B cells are absent or inactive
Acquired Immune Deficiency Syndrome (AIDS)Acquired Immune Deficiency Syndrome (AIDS) Human immunodeficiency virus (HIV)Human immunodeficiency virus (HIV)
Primarily attacks helper T cellsPrimarily attacks helper T cells