The Lymphatic System Functions - PowerPoint Presentation

Slide1

The Lymphatic System

Slide2

Functions

1. Transport fluids = excess

interstitial fluids are returned to the cardiovascular system2. Immunity = houses and transports lymphocytes3. Transport lipids = circulates fats, like vitamins D,E,A,K, that were absorbed by GI tract

Image courtesy of

www.lepra.org

Lymphatic

filariasis

Slide3

Anatomy

1.

Lymph (the fluid)2. Vessels (the tubes)3. Cells (WBC’s for immunity)4. Tissues (

nonencapsulated small clusters of lymphatics)5.

Organs (

encapsulated lymphatic structures)Note: the lymphatic system has

no pump to circulate thefluids, movement of fluid is passive and similar to venousblood return to the heart.

Slide4

Lymph

Fluid in

circulatory system is plasmawhen it leaves capillaries it becomes interstitial fluidwhen it enters the lymphatic capillary it becomes lymph Usually its clear, except in intestines where it is white (lacteals) and cloudy because of freshly absorbed fats

(lymph here is called chyle)

Slide5

Vessels

Capillaries

(20.1)

↓

Endothelium,

1

-way mini

Valves,

Anchoring

Filaments,

Blind ends,

Called

lacteals

near intestine,

None

in bone or CNS

Collecting

Vessels

↓3 tunicas(like veins)Travel with arteries & veinsNodes periodically

Trunks↓Drain regionsFive:R & L LumbarR & L JugularR & L Bronco-MediastinalR & L SubclavianIntestinal (unpaired)

Ducts↓Join CV systemat junctionof Jugularand SubclavianVeinsTwo:R. LymphaticThoracic

Slide6

Slide7

Cells

Lymphocytes

= T & B cells for specific immunityMacrophages (monocytes) = phagocytosis and antigen presentationDendritic cells =

phagocytosis and antigen presentationReticular cells = make the

stroma

of the lymph tissue and support the WBC’s

Slide8

Immunity

Slide9

Innate - Nonspecific Defenses

First Line of Defense = Surface Barriers Forms physical & chemical barriersA. SkinMany layers

, tight junctionsWhen intact it forms an excellent barrier

B. Mucous membranes

When intact does form a barrier

MucusCilia

Slide10

First Line of Defense (cont.)

C

. Other barriersLacriminal fluids = tears wash the surface of the eyesSaliva = washes the mouth/teethSebum = makes protective film over surface & has chemical that inhibits microbial growthAcidity (skin, vagina, stomach) inhibits

microbial growth

Slide11

Nonspecific Defenses (cont.)

Second Line of Defense

Cells Phagocytes Non-phagocytesB. InflammationC. Antimicrobial Proteins Complement InterferonD. Fever

Slide12

Specific Defenses (Immunity)

A specific immune response is

provoked when microbes colonizeInvolves a coordinated attack by B and T lymphocytes Results in Memory cells Two branches

Humoral (Antibody-Mediated) = involves the production of

antibodies

by B cells (particularly good for microbes in body fluids

) 2. Cellular (Cell-Mediated) = involves T cells directly attacking the microbe (particularly good for microbes hiding inside cells)

Slide13

Two Classes of MHC proteins:

MHC I

are found on all body cells except RBC’sB & T cells do not respond to these proteins when they are “normal”Infected body cells/cancerous cells have abnormal MHC I proteins and will provoke a reaction

MHC II are found on various immune cells

Usually will include pieces of the

microbeUsed to present the antigen to other immune

cells

Slide14

Humoral Immunity – antibody mediated

Involves

B-Lymphocytes making antibodiesB-cells have receptors (BCR) that allow them to recognize “non-self”They can bind directly to antigenThey can process antigen and display it to other immune cells on an

MHCII

Slide15

Humoral/Antibody-Mediated Immunity (cont.)

Clonal Selection

The immune response begins when the B-cell receptors (BCR) binds to specific antigen

Slide16

Humoral/Antibody-Mediated Immunity (cont.)

Once activated by

binding

B-Cells clone

Most

Enlarge and become

plasma cells

Plasma

cells

secrete

antibodies

Into body fluids

Antibodies

bind

to antigen

Some become

Memory

B-cells

Slide17

Humoral Immunity (cont.)

Plasma

cells secrete antibodiesinto body fluidsAntibodies circulate and bind toantigen

Microbe

with antigen

Antibody

Slide18

Humoral/Antibody-Mediated Immunity (cont.)

Slide19

Cell-Mediated Immunity

Involves the T-Lymphocytes directly attacking the antigensTwo major T-cell populations: Classification by cell membrane co-receptors:CD4 cells = Helper T cells (TH

)CD8 cells = Cytotoxic cells (T

C

)

Slide20

Cell-Mediated Immunity (cont.)

T

-Lymphocytes can not bind directly to free antigensAntigen must be “presented” to T-cells bound to an MHC

Infected body cells present antigen on

MHCI

Slide21

Cell-Mediated Immunity (cont.)

Other immune cells

(

macrophages, B-cells,

Dendritic cells

)

present antigen on MHCII

Slide22

Cell-Mediated Immunity (cont.)

The immune response begins when the

T-cell receptors (TCR) binds to the antigen (specificity)TCR/CD8 receptors on TC bind to abnormal MHC I presenting antigen

TCR/CD4 receptors on TH

bind

MHC II presenting antigen

BODY CELL

IMMUNE CELL

Slide23

Cell-Mediated Immunity (cont.)

Activation requires costimulation

After the initial binding B7 proteins (made when innate immune system is stimulated) on the APC bind to CD28 receptors on the T cellsAfter binding occurs chemical stimulation is required for the immune reaction to proceed

CD8

MHCI

CD4

MHCII

Slide24

Cell-Mediated Immunity (cont.)

Once activated by

binding and costimulation, the T-lymphocyte rapidly divides to create an army of clones to fight the specific antigen

CD4

CD8

Slide25

Cell-Mediated Immunity (cont.)

Activated, Cloned Helper-

T Cells (CD4) release chemicals that:Stimulate Cytotoxic T cellsStimulate B cellsEnhance activity of macrophages and NK’s

Slide26

Cell-Mediated Immunity (cont.)

Activated, cloned

Cytotoxic T- Lymphocytesdirectly attack microbe with the specific antigenPerforins = make holes in membranesGranzymes = destroy proteins

Slide27

Cell-Mediated Immunity (cont.)

Memory

T-Lymphocytes will attack the microbe more quickly next time it enters

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Slide29

The Digestive System

Slide30

Slide31

Digestive

Processes

(fig.23.2)