The Lymphatic System. Introduction The ability to ward off pathogens that produce disease is called resistance The ability to ward off pathogens that.

The Lymphatic SystemThe Lymphatic System

IntroductionIntroduction

The ability to ward off pathogens that The ability to ward off pathogens that produce disease is called produce disease is called resistanceresistance

IntroductionIntroduction

Lack of resistance is called Lack of resistance is called susceptibilitysusceptibility

Lymphatic SystemLymphatic System

Consist of;Consist of; lymph (fluid)lymph (fluid) lymphatic vesselslymphatic vessels lymphatic organs and tissueslymphatic organs and tissues bone marrowbone marrow


Functions;Functions;

1.1. Drain interstitial fluidDrain interstitial fluid


2. Return leaked plasma proteins to 2. Return leaked plasma proteins to the bloodthe blood


3. Protects against invasion by 3. Protects against invasion by nonspecific defenses and specific nonspecific defenses and specific immune responsesimmune responses

Lymphatic CirculationLymphatic Circulation

Interstitial fluid drains into lymphatic Interstitial fluid drains into lymphatic capillaries thus forming lymphcapillaries thus forming lymph


Lymph capillaries merge to form Lymph capillaries merge to form larger vessels, called lymphatic larger vessels, called lymphatic vesselsvessels


Convey lymph into and out of Convey lymph into and out of structures called lymph nodesstructures called lymph nodes

Lymphatic CapillariesLymphatic Capillaries

Lymphatic capillaries are found Lymphatic capillaries are found everywhere except;everywhere except;

1. Avascular tissue1. Avascular tissue


2. CNS2. CNS


3. Portions of the spleen3. Portions of the spleen


4. Red bone marrow4. Red bone marrow


Lacteal – lymphatic capillary in the Lacteal – lymphatic capillary in the villus of the small intestine which villus of the small intestine which transport fatstransport fats

Lymph Trunk and DuctsLymph Trunk and Ducts

1.1. Thoracic DuctThoracic Duct

2.2. Right Lymphatic DuctRight Lymphatic Duct

Thoracic DuctThoracic Duct

Main collecting duct of the lymphatic Main collecting duct of the lymphatic systemsystem


Receives lymph from the left side of Receives lymph from the left side of the head, neck, and chest, the left the head, neck, and chest, the left upper extremity and the entire body upper extremity and the entire body below the ribsbelow the ribs


It drains lymph into venous blood via It drains lymph into venous blood via the left subclavian veinthe left subclavian vein

Right Lymphatic DuctRight Lymphatic Duct

Drains lymph from the upper right Drains lymph from the upper right side of the bodyside of the body

Right Lymphatic DuctRight Lymphatic Duct

It drains lymph into venous blood via It drains lymph into venous blood via the right subclavian veinthe right subclavian vein

Flow of LymphFlow of Lymph

1. Fluid flows from arteries and blood 1. Fluid flows from arteries and blood capillaries to interstitial spaces capillaries to interstitial spaces (interstitial fluid)(interstitial fluid)


2. To lymph capillaries (lymph)2. To lymph capillaries (lymph)


3. To lymphatic vessels3. To lymphatic vessels


4. To lymph trunks4. To lymph trunks


5.To the thoracic duct or right 5.To the thoracic duct or right lymphatic duct lymphatic duct


6. To the subclavian veins (blood)6. To the subclavian veins (blood)

Lymphatic Organs and TissuesLymphatic Organs and Tissues

Lymphatic organs are classified as Lymphatic organs are classified as primary or secondaryprimary or secondary

Primary Lymphatic OrgansPrimary Lymphatic Organs

Red bone marrowRed bone marrow Thymus glandThymus gland

Secondary Lymphatic OrgansSecondary Lymphatic Organs

Lymph nodesLymph nodes SpleenSpleen Lymphatic nodulesLymphatic nodules

Thymus GlandThymus Gland

Lies between the sternum and the Lies between the sternum and the heartheart


Functions in immunity as the site of T Functions in immunity as the site of T cell maturationcell maturation


Large in the infant and after puberty Large in the infant and after puberty it is replaced by adipose and areolar it is replaced by adipose and areolar connective tissueconnective tissue

Lymph NodesLymph Nodes

Are encapsulated oval structures Are encapsulated oval structures located along lymphatic vesselslocated along lymphatic vessels


Contain T cells, macrophages, Contain T cells, macrophages, follicular dendritic cells, B cells, and follicular dendritic cells, B cells, and plasma cellsplasma cells


Lymph enters nodes through afferent Lymph enters nodes through afferent lymphatic vessels and is filtered to lymphatic vessels and is filtered to remove damage cells and remove damage cells and microorganismsmicroorganisms


Exits through efferent lymphatic Exits through efferent lymphatic vesselvessel


Foreign substances filtered by the Foreign substances filtered by the lymph nodes are trapped by nodal lymph nodes are trapped by nodal reticular fibersreticular fibers


Macrophages destroys foreign Macrophages destroys foreign substances by phagocytosissubstances by phagocytosis


Lymphocytes bring about the Lymphocytes bring about the destruction of others by immune destruction of others by immune responseresponse


Site of proliferation of plasma cells Site of proliferation of plasma cells (from B cells) and T cells(from B cells) and T cells

Plasma cells make antibodiesPlasma cells make antibodies

SpleenSpleen

Largest mass of lymphatic tissue in Largest mass of lymphatic tissue in the bodythe body

SpleenSpleen

Located between the stomach and Located between the stomach and diaphragmdiaphragm

SpleenSpleen

Made up of Made up of white white and and red pulpred pulp

White PulpWhite Pulp

Lymphatic TissueLymphatic Tissue


Its T lymphocytes directly attack and Its T lymphocytes directly attack and destroy antigens in blooddestroy antigens in blood


Its B lymphocytes develop into Its B lymphocytes develop into antibody producing plasma cells, and antibody producing plasma cells, and the antibodies inactivate antigens in the antibodies inactivate antigens in bloodblood


Macrophages destroy antigens in Macrophages destroy antigens in blood by phagocytosisblood by phagocytosis

Red PulpRed Pulp

Consists of;Consists of;

1.1. Venous sinusesVenous sinuses

2.2. Splenic cordsSplenic cords

Red PulpRed Pulp

Venous sinuses are filled with bloodVenous sinuses are filled with blood

Red PulpRed Pulp

Splenic cords consist of;Splenic cords consist of;

1.1. RBCsRBCs

2.2. MacrophagesMacrophages

3.3. LymphocytesLymphocytes

4.4. Plasma cellsPlasma cells

5.5. granulocytesgranulocytes

Red PulpRed Pulp

Macrophages remove deffective Macrophages remove deffective RBCs, WBCs, and plateletsRBCs, WBCs, and platelets

Red PulpRed Pulp

Stores blood plateletsStores blood platelets

Lymphatic NodulesLymphatic Nodules

Oval-shaped concentrations of Oval-shaped concentrations of lymphatic tissuelymphatic tissue

Lymphatic NodulesLymphatic Nodules

Scattered throughout the mucous Scattered throughout the mucous membranes lining the GI tract, membranes lining the GI tract, respiratory airways, urinary tract, respiratory airways, urinary tract, and reproductive tractand reproductive tract

Peyer’s patchesPeyer’s patches

Lymphatic nodules in the ileum of Lymphatic nodules in the ileum of the small intestinethe small intestine

TonsilsTonsils

Multiple aggregations of large Multiple aggregations of large lymphatic nodules at the junction of lymphatic nodules at the junction of the oral cavity and the pharynxthe oral cavity and the pharynx

TonsilsTonsils

Include;Include;

1.1. PharyngealPharyngeal

2.2. PalatinePalatine

3.3. Lingual tonsilsLingual tonsils

TonsilsTonsils

Participate in immune responses by Participate in immune responses by producing lymphocytes and producing lymphocytes and antibodiesantibodies

Nonspecific Resistance to DiseaseNonspecific Resistance to Disease

Involves a Involves a

1.1. First line of DefenseFirst line of Defense

2.2. Second line of DefenseSecond line of Defense

First Line of DefenseFirst Line of Defense

InvolvesInvolves

1.1. Mechanical ProtectionMechanical Protection

2.2. Chemical ProtectionChemical Protection

Mechanical ProtectionMechanical Protection

IncludeInclude

1. Epidermis layer of the skin1. Epidermis layer of the skin


2. Mucous membranes in the nose 2. Mucous membranes in the nose and tracheaand trachea


3. Lacrimal apparatus3. Lacrimal apparatus


4. Saliva4. Saliva


5. Mucus5. Mucus


6. Cilia6. Cilia


7. Epiglottis7. Epiglottis


8. Flow of urine8. Flow of urine


9. Defecation9. Defecation


10. Vomiting10. Vomiting

Chemical ProtectionChemical Protection

1. The skin produces 1. The skin produces sebumsebum, which , which has a low pHhas a low pH


2. 2. LysozymeLysozyme in sweat has in sweat has antimicrobial propertiesantimicrobial properties


3. 3. Gastric juiceGastric juice in the stomach has in the stomach has a low pHa low pH


4. 4. Vaginal secretionsVaginal secretions are also are also acidicacidic

Second Line of DefenseSecond Line of Defense

InvolvesInvolves

1.1. Antimicrobial proteinsAntimicrobial proteins

2.2. Phagocytic and natural killer cellsPhagocytic and natural killer cells

3.3. InflammationInflammation

4.4. FeverFever

Antimicrobial Proteins Antimicrobial Proteins

1.1. InterferonsInterferons

2.2. Complement SystemComplement System

InterferonsInterferons

Body cells infected with viruses Body cells infected with viruses produce proteins called interferons produce proteins called interferons (IFNs)(IFNs)


IFN diffuses to uninfected cells and IFN diffuses to uninfected cells and binds to surface receptorsbinds to surface receptors


This induces uninfected cells to This induces uninfected cells to synthesize antiviral proteins that synthesize antiviral proteins that inhibit viral replicationinhibit viral replication

Complement SystemComplement System

A group of 20 proteins present in A group of 20 proteins present in blood plasma and on cell membranesblood plasma and on cell membranes

Complement SystemComplement System

When activated, these proteins When activated, these proteins enhance immune, allergic, and enhance immune, allergic, and inflammatory reactionsinflammatory reactions

Natural Killer CellsNatural Killer Cells

Lymphocytes that lack the Lymphocytes that lack the membrane molecules that identify T membrane molecules that identify T and B cellsand B cells


Can kill a variety of infectious Can kill a variety of infectious microbes and some tumor cells microbes and some tumor cells


Sometime release Sometime release perforins perforins that that insert into the plasma membrane of insert into the plasma membrane of a microbe and make the membrane a microbe and make the membrane leaky so that cytolysis occursleaky so that cytolysis occurs


Sometimes they bind to a target cell Sometimes they bind to a target cell and inflict damage by direct contactand inflict damage by direct contact

PhagocytesPhagocytes

Neutrophils and macrophagesNeutrophils and macrophages

InflammationInflammation

Four symptomsFour symptoms

1.1. RednessRedness

2.2. PainPain

3.3. HeatHeat

4.4. SwellingSwelling


Three stagesThree stages

1.1. Vasodilation and increased Vasodilation and increased permeabilitypermeability


2. Emigration of phagocytes from the 2. Emigration of phagocytes from the blood into interstitial fluidblood into interstitial fluid


3. Tissue Repair3. Tissue Repair


Vasodilation and increased Vasodilation and increased permeability are responsible for heat, permeability are responsible for heat, redness, and swellingredness, and swelling


Pain results from injury to neurons Pain results from injury to neurons and from toxic chemicals released by and from toxic chemicals released by microbesmicrobes

FeverFever

When macrophages respond to an When macrophages respond to an infection, they release infection, they release interleukin interleukin -1-1

FeverFever

Interleukin-1 stimulates the Interleukin-1 stimulates the hypothalamus to initiate a fever hypothalamus to initiate a fever

FeverFever

Inhibits some microbial growth and Inhibits some microbial growth and speeds up body reactions that aid speeds up body reactions that aid repairrepair

Major Histocompatibility Complex Major Histocompatibility Complex AntigensAntigens

Unique to each person’s body cellsUnique to each person’s body cells


All cells except rbc display All cells except rbc display MHC class MHC class II antigens antigens


Antigen presenting cells Antigen presenting cells (macrophages) also display (macrophages) also display MHC MHC class IIclass II antigens antigens

Pathways of Antigen ProcessingPathways of Antigen Processing

For an immune response to occur, B For an immune response to occur, B and T cells must recognize that a and T cells must recognize that a foreign antigen is presentforeign antigen is present


Antigens are chemical substances Antigens are chemical substances that are recognized as foreign by that are recognized as foreign by antigen receptors when introduced antigen receptors when introduced into the bodyinto the body


The body contains millions of The body contains millions of different T and B cells each capable different T and B cells each capable of responding to a specific antigenof responding to a specific antigen

Cell-Mediated ImmunityCell-Mediated Immunity

Refers to destruction of antigens by T Refers to destruction of antigens by T cellscells


Three main stepsThree main steps


1. T cells recognize antigen fragments 1. T cells recognize antigen fragments associated with MHC II class associated with MHC II class molecules on the surface of an molecules on the surface of an antigen presenting cell antigen presenting cell (macrophage). (macrophage).


Although CD8 cell receptors bind to Although CD8 cell receptors bind to the antigen associated with MHC the antigen associated with MHC class I molecules on the virus class I molecules on the virus infected cellinfected cell


2. A small number of T cells proliferate 2. A small number of T cells proliferate and differentiate into a clone of and differentiate into a clone of effector cellseffector cells


2 continued …2 continued …

Clone of effector cells – a pop. of Clone of effector cells – a pop. of identical cells that can recognize the identical cells that can recognize the same antigensame antigen


3. Antigen (intruder) is eliminated 3. Antigen (intruder) is eliminated

Types of T CellsTypes of T Cells

1.1. Helper T (TH) cellsHelper T (TH) cells

2.2. Cytotoxic T (TC) cellsCytotoxic T (TC) cells

3.3. Memory T cellsMemory T cells

Helper T cellsHelper T cells

T4 cellsT4 cells


Display CD4 proteinsDisplay CD4 proteins


Recognize antigen fragments Recognize antigen fragments associated with MHC-II moleculesassociated with MHC-II molecules


Secrete interleukin-2 which as a Secrete interleukin-2 which as a costimulatorcostimulator


Proliferation of T cells requires Proliferation of T cells requires costimulationcostimulation

Cytotoxic T cellsCytotoxic T cells

Fight foreign invaders by killing the Fight foreign invaders by killing the target celltarget cell


Target cell – the cell that bears the Target cell – the cell that bears the same antigen that stimulated same antigen that stimulated proliferationproliferation


One killing mechanism uses One killing mechanism uses perforin perforin to cause cytolysis of the target cell.to cause cytolysis of the target cell.


The second mechanism uses The second mechanism uses lymphotoxinlymphotoxin to activate damaging to activate damaging enzymes within the target cellsenzymes within the target cells


Main targets are virus infected cellsMain targets are virus infected cells

Memory T cellsMemory T cells

Programmed to recognize the Programmed to recognize the original invading antigenoriginal invading antigen

Antibody-Mediated ImmunityAntibody-Mediated Immunity

Refers to destruction of antigens by Refers to destruction of antigens by antibodiesantibodies


There are 4 stepsThere are 4 steps


1. An antigen binds to the surface of 1. An antigen binds to the surface of B cellsB cells


2. Some antigen is taken into the B 2. Some antigen is taken into the B cell, broken down into peptide cell, broken down into peptide fragments and combined with the fragments and combined with the MHC-II self antigen, and moved to MHC-II self antigen, and moved to the B cell surfacethe B cell surface


3. Hepler T cells recognize the 3. Hepler T cells recognize the antigen-MHC-II combination and antigen-MHC-II combination and secrete interleukinssecrete interleukins


The interleukins deliver the The interleukins deliver the costimulation needed for B cell costimulation needed for B cell proliferationproliferation


4. Some activated B cells become 4. Some activated B cells become antibody-secretion plasma cells. antibody-secretion plasma cells. Others become B cellsOthers become B cells

AntibodiesAntibodies

A protein that can combine A protein that can combine specifically with the antigenic specifically with the antigenic determinant on the antigen that determinant on the antigen that triggered its productiontriggered its production

AntibodiesAntibodies

Five classesFive classes

1.1. IgGIgG

2.2. IgAIgA

3.3. IgMIgM

4.4. IgDIgD

5.5. IgEIgE

IgGIgG

It binds to bacteria and viruses It binds to bacteria and viruses

IgGIgG

It crosses the placenta until it can It crosses the placenta until it can begin secreting its own.begin secreting its own.

IgAIgA

It is in blood, breast milk, tears, It is in blood, breast milk, tears, saliva, and intestinal secretions.saliva, and intestinal secretions.

IgAIgA

Levels decrease during stressLevels decrease during stress

IgAIgA

Protects our mucous membranes Protects our mucous membranes against infections with bacteria and against infections with bacteria and virusesviruses

IgMIgM

First antibody to be secreted by First antibody to be secreted by plasma cells after exposure to plasma cells after exposure to antigensantigens

IgMIgM

Antibodies to A and B red cell Antibodies to A and B red cell antigens are IgMantigens are IgM

IgMIgM

Cannot cross the placentaCannot cross the placenta

IgDIgD

Activate B cellsActivate B cells

IgEIgE

On the surface of mast cells and On the surface of mast cells and basophilsbasophils

IgEIgE

Involved in allergic reactionsInvolved in allergic reactions

IgEIgE

When a person with pollen allergies When a person with pollen allergies inhales pollen, it combines with the inhales pollen, it combines with the IgE on their mast cellsIgE on their mast cells

IgEIgE

Causes mast cells to release Causes mast cells to release histaminehistamine

AIDSAIDS

A condition in which a person A condition in which a person experiences infections as a result of experiences infections as a result of the progressive destruction of cells the progressive destruction of cells by the humon immunodeficiency by the humon immunodeficiency virusvirus

HIVHIV

The only documented transmissions The only documented transmissions are by way of blood, semen, vaginal are by way of blood, semen, vaginal secretions, and breast milksecretions, and breast milk

HIVHIV

A recent study in San Fran showed A recent study in San Fran showed that 8% of their HIV-infected patients that 8% of their HIV-infected patients acquired it via oral sexacquired it via oral sex

HIVHIV

Form of a retrovirus with a protein Form of a retrovirus with a protein coatcoat

HIVHIV

HIV enters CD4 positive T HIV enters CD4 positive T lymphocytes and macrophages lymphocytes and macrophages where it sheds its protein coatwhere it sheds its protein coat

HIVHIV

New HIV DNA is produced in the T New HIV DNA is produced in the T cell along with new protein coats and cell along with new protein coats and then releasedthen released

HIVHIV

The T cells are ultimately destroyedThe T cells are ultimately destroyed

HIVHIV

Progression to AIDS occurs because Progression to AIDS occurs because of reduced numbers of T cells and of reduced numbers of T cells and resulting immunodeficiencyresulting immunodeficiency

AIDSAIDS

Person now susceptible to Person now susceptible to opportunistic infectionsopportunistic infections

HIVHIV

Treatment of HIV infection with Treatment of HIV infection with reverse transcriptase inhibitors has reverse transcriptase inhibitors has shown to delay the progression of shown to delay the progression of HIV infection to AIDSHIV infection to AIDS

The Lymphatic System. Introduction The ability to ward off pathogens that produce disease is called resistance The ability to ward off pathogens that.

Documents

lymphatic duct slide

lymph capillaries lymph

lymphatic system slide

resistance slide

body slide

lymphatic duct drains

susceptibility slide

spleen slide