Lymphatic SystemLymphatic System

11--The lymphatic tissues which areThe lymphatic tissues which are::

A-Lymph nodesA-Lymph nodes

B-SpleenB-Spleen

C-Scattered lymphatic nodulesC-Scattered lymphatic nodules

D-TonsilsD-Tonsils

22--The Lymphatic vessels: the lymphatic The Lymphatic vessels: the lymphatic capillaries and lymph vessels;the carry the capillaries and lymph vessels;the carry the lymphlymph

Formation of lymphFormation of lymph

Tissue fluid which is filtered from the Tissue fluid which is filtered from the tissues and from the blood capillaries tissues and from the blood capillaries around the cells is drained by blind-ended around the cells is drained by blind-ended lymphatic capillarieslymphatic capillaries

The fluid when enters the lymphatic The fluid when enters the lymphatic vessels called lymphvessels called lymph

The lymph is filtred in lymph The lymph is filtred in lymph nodes&nodulesnodes&nodules

Lymph flows in one direction inside the Lymph flows in one direction inside the lymphatic capillarieslymphatic capillaries

The filtred lymph go again to the blood The filtred lymph go again to the blood stream through alarge lymphatic vessels stream through alarge lymphatic vessels called thoracic ductcalled thoracic duct

LYMPHATIC SYSTEM

artery

vein

lymphaticsinusoid

lymphatic capillary

bloodcapillariesvenule

arteriole

LYMPHATIC CAPILLARY

LYMPHATIC SINUSOID

Differences between Differences between blood capillariesblood capillaries & & lymphatic capillarieslymphatic capillaries

Blood CapillariesBlood Capillaries Lymphatic capillariesLymphatic capillaries11)) Present superficialPresent superficial in position in position

under the skin & mucous membraneunder the skin & mucous membrane..11 ) )Present more deepPresent more deep in position in position

than blood capillariesthan blood capillaries

22))They are the branching vessels of They are the branching vessels of arterioles & are connected with arterioles & are connected with venules at the other sidevenules at the other side..

22))They start as blind – ended channels They start as blind – ended channels & are connected to lymph vessels at & are connected to lymph vessels at one side onlyone side only..

33))They have They have uniformuniform diameters diameters33))Their diameters are Their diameters are irregularirregular

44))The endothelium is The endothelium is fenestratedfenestrated 44 ) )Non-fenestrated Non-fenestrated endotheliumendothelium

55))They are surrounded with basement They are surrounded with basement membranes & pericytesmembranes & pericytes..

55))They have no basement membrane They have no basement membrane & no pericytes& no pericytes..

66))The lumen is usually patentThe lumen is usually patent66))The lumen may be The lumen may be collapsedcollapsed..

77))No anchoring collagenous fibers No anchoring collagenous fibers outside their walloutside their wall

77 ) )Anchoring collagenous fibersAnchoring collagenous fibers connect their wall to surrounding C.Tconnect their wall to surrounding C.T..

88))They carry bloodThey carry blood..88))They carry lymphThey carry lymph..

Structures Of Lymph vesselsStructures Of Lymph vessels

Large lymphatic vessels are formed of Large lymphatic vessels are formed of intima,media, adventitiaintima,media, adventitia

Similar to venis,they also have valvesSimilar to venis,they also have valves

Lymph nodesLymph nodes

Shape&functionShape&function

Kidney shaped organs present along the Kidney shaped organs present along the course of lymphatic vesselscourse of lymphatic vessels

Function: filter the lymph form any Function: filter the lymph form any organisme or forign bodyorganisme or forign body

Contain lymphocytes,macrophages,killer Contain lymphocytes,macrophages,killer cells&plasma cellscells&plasma cells

Site of lymph nodes:Site of lymph nodes:present in groups in present in groups in the the axilla,neck,groin,thorax,abdomen7poplitealaxilla,neck,groin,thorax,abdomen7popliteal&cubital areas&cubital areasSize;Size; small,large in abnormal change small,large in abnormal change afferent lymph vessels; bring lymph to afferent lymph vessels; bring lymph to lymph nodeslymph nodesEfferent lymph carry lymph away from Efferent lymph carry lymph away from lymph nodeslymph nodes

Structures of lymph nodeStructures of lymph node

Is formed of C.T.stroma&parenchyma ofIs formed of C.T.stroma&parenchyma of::

SromaSroma

C.T. framework the lymph node includeC.T. framework the lymph node include

11--C.T.capsuleC.T.capsule

22--C.T.trabeculaeC.T.trabeculae

33--Reticular C.T.networkReticular C.T.network

CapsuleCapsule

Collagenous&elastic C.T.fibres separated Collagenous&elastic C.T.fibres separated by C.T. cells,smooth muscle are present at by C.T. cells,smooth muscle are present at the hilum of lymph nodesthe hilum of lymph nodes

Trabeculae:Trabeculae:formed of C.T. formed of C.T. cells&fibers,divid the cortex of lymph node cells&fibers,divid the cortex of lymph node into compartmentinto compartment

33--Reticular NetworkReticular Network::

Fine network of reticular C.T. formed of Fine network of reticular C.T. formed of dendretic reticular cells&reticular fibresdendretic reticular cells&reticular fibres

Condensed more in cortex than in the Condensed more in cortex than in the medulla stained by silver stainmedulla stained by silver stain

Cells of the stroma of the lymph Cells of the stroma of the lymph nodenode

A-Dendrtic Reticular Cells: they are A-Dendrtic Reticular Cells: they are branched cells with multiple cytoplasmic branched cells with multiple cytoplasmic processesprocesses

Non-phagocytic cells,they are present in Non-phagocytic cells,they are present in large numbers near B-lymphocyteslarge numbers near B-lymphocytes

B-Macrophages cells: they are branched B-Macrophages cells: they are branched cells with large nucleicells with large nuclei

They phagocytose foreign bodies,they are They phagocytose foreign bodies,they are antigen presenting cells,secrete antigen presenting cells,secrete interleukin-I which regulates proliferation interleukin-I which regulates proliferation of lymphocytesof lymphocytes

C-Fibroblast cells:they are present mainly C-Fibroblast cells:they are present mainly around blood&lymph vesselsaround blood&lymph vessels

The parenchymal of lymph nodeThe parenchymal of lymph node

Parenchyma are functioning cells of the Parenchyma are functioning cells of the lymph nodelymph node

Cortex;localized in the center of lymph Cortex;localized in the center of lymph nodes,irregular condensedationnodes,irregular condensedation

The cortex of the lymph node containsThe cortex of the lymph node contains

11--cortical lymphatic nodulescortical lymphatic nodules

22--cortical lymphatic sinusescortical lymphatic sinuses

11--The cortical lymphatic noduleThe cortical lymphatic nodule

are of two typesare of two types

a-primary lymphatic nodulesa-primary lymphatic nodules

b-secondary lymphatic nodulesb-secondary lymphatic nodules

A-primary lymphatic nodules of A-primary lymphatic nodules of follicles(aggregation of lymphocytes without follicles(aggregation of lymphocytes without germinal center)germinal center)

--they are rounded,ovalthey are rounded,oval

--present under the capsule of lymph nodepresent under the capsule of lymph node

Aggregates of small lymphocytesAggregates of small lymphocytes

When the primary lymphatic nodules are When the primary lymphatic nodules are exposed to infections or any antigens,small exposed to infections or any antigens,small lymphocyte develop into activatedlymphocyte develop into activated

medium sized lymphocytes,newly formed medium sized lymphocytes,newly formed activated lymphocytes aggregates in the activated lymphocytes aggregates in the center of the primary lymphatic nodules to center of the primary lymphatic nodules to form germinal centers&primary nodule form germinal centers&primary nodule changed into secondary lymphatic nodulechanged into secondary lymphatic nodule

B-The secondary lymphatic B-The secondary lymphatic nodulesnodules

Formed of the following cellsFormed of the following cells

A-activated medium sized B-lymphocytesA-activated medium sized B-lymphocytes

B-T-lymphocytes&macrophagesB-T-lymphocytes&macrophages

C-Dendrtic reticular cellsC-Dendrtic reticular cells

22--The cortical lymphatic sinusesThe cortical lymphatic sinuses

Spaces which are present between the Spaces which are present between the covering capsule&cortical lymphatic covering capsule&cortical lymphatic folliclesfollicles

They are lined with flat endothelial cellsThey are lined with flat endothelial cells

The cortical sinuses contain B-The cortical sinuses contain B-lymphocytes,macrophages&plasma cellslymphocytes,macrophages&plasma cells

The Medulla of lymph nodeThe Medulla of lymph node

Formed ofFormed of

11--Medullary lymphatic cordMedullary lymphatic cord

--are irregular collections of are irregular collections of lymphocyes&plasma cellslymphocyes&plasma cells

--containous with the cortical folliclescontainous with the cortical follicles

--seperated from each other by medullary seperated from each other by medullary lymphatic sinuseslymphatic sinuses

22--Medullary lymphatic sinusesMedullary lymphatic sinuses

--irregular wide spaces between the irregular wide spaces between the medullary cordsmedullary cords

--lined with flat endothelial cellslined with flat endothelial cells

--contain free lymphocytes,macrophages contain free lymphocytes,macrophages and some plasma cellsand some plasma cells

Circulation of lymph inside the Circulation of lymph inside the lymph nodelymph node

--lymph enters the lymph node by afferent lymph enters the lymph node by afferent lymph vessels through its cortexlymph vessels through its cortex

--the lymph is filted through the the lymph is filted through the cortical&medullary sinuses then the lymph cortical&medullary sinuses then the lymph leaves the node through efferent lymph leaves the node through efferent lymph vessels at is hilumvessels at is hilum

Blood supply of lymph nodeBlood supply of lymph node

Arteries enter the lymph nodes at Arteries enter the lymph nodes at hilum,branches pass to the cortex where hilum,branches pass to the cortex where they branch to form arterial capillariesthey branch to form arterial capillaries

The venous capillaries:desend from the The venous capillaries:desend from the cortex to form post-capillary venules which cortex to form post-capillary venules which lined by simple cubical cells collected lined by simple cubical cells collected veins leave the node at the hilumveins leave the node at the hilum

Cells present in the lymph nodesCells present in the lymph nodes

11--B-Lymphocytes:common cells in both B-Lymphocytes:common cells in both cortexand medullacortexand medulla

22--T-lymphocytes: present in thymus T-lymphocytes: present in thymus dependent zonesdependent zones

33--Macrophages:present inwhole stroma of Macrophages:present inwhole stroma of lymph nodelymph node

44--Plasmablasts:present in cortex&medullaPlasmablasts:present in cortex&medulla

66--Endothelial cells:lining the Endothelial cells:lining the cortical&medullary lymphcortical&medullary lymph

77--plasma cells;present in cortex and plasma cells;present in cortex and medulla of lymph nodemedulla of lymph node

88--Endothelial cells:lining the cortical and Endothelial cells:lining the cortical and medullary lymphatic sinusesmedullary lymphatic sinuses

Function of lymph nodesFunction of lymph nodes

11--filtration of lymphfiltration of lymph

22--formation of lymphocytesformation of lymphocytes

33--production of antibodies formation of production of antibodies formation of these immunoglobalin IgG,IgA,IgE,IgDthese immunoglobalin IgG,IgA,IgE,IgD

SpleenSpleen

--single intra-abdomenal haemolymphatic single intra-abdomenal haemolymphatic organorgan

--general filter for circulating bloodgeneral filter for circulating blood--has no afferent lymph vessels it has only has no afferent lymph vessels it has only

efferent lymph vesselsefferent lymph vesselsStructures of spleenStructures of spleenFormed of C.T. stroma&parenchyma of Formed of C.T. stroma&parenchyma of lymphoid tissuelymphoid tissue

Stroma of spleenStroma of spleen

C.T. framework which includesC.T. framework which includes

A-capsuleA-capsule,,

B-TrabeculaeB-Trabeculae

C-Reticular C.TC-Reticular C.T..

11--Capsule:Capsule:covered peritoneumcovered peritoneumFormed of collagenous&elastic Formed of collagenous&elastic C.T.fibres&fibroblast cellsC.T.fibres&fibroblast cellsThe capsule is rich in smoth muscleThe capsule is rich in smoth muscle

22--trabeculae:trabeculae:formed of C.T.cells and fibresformed of C.T.cells and fibresThe trabeculae is tich in smooth muscleThe trabeculae is tich in smooth muscle

33--Reticular network:Reticular network:made up of reticular fibres made up of reticular fibres and cellsand cellsIt can stained brown with silver stainIt can stained brown with silver stainThe reticular network is more condensed in the The reticular network is more condensed in the white pulp than red pulpwhite pulp than red pulp

The ParenchymaThe Parenchyma

Composed of white&red pulpComposed of white&red pulpWhite pulp or (malpighian corpuscles)White pulp or (malpighian corpuscles)They are rounded or elongated lymphatic They are rounded or elongated lymphatic nodulesnodulesFormed of reticular C.T. upon which T-Formed of reticular C.T. upon which T-lymphocytes,plasm cells and macrophages are lymphocytes,plasm cells and macrophages are present at its periphery and B-present at its periphery and B-Lymphocytes,plasma cells and macrophages Lymphocytes,plasma cells and macrophages are present at its pale germinal centersare present at its pale germinal centers

The blood sinusoidsThe blood sinusoids

--Irregular wide blood channels lined with Irregular wide blood channels lined with flat endothelial cellsflat endothelial cells

--They are surrounded by non-continous They are surrounded by non-continous basement membranesbasement membranes

--macrophages cells are present in the wall macrophages cells are present in the wall of sinusoidsof sinusoids

Differences between Differences between capillaries capillaries & & sinusoidssinusoids

CapillariesCapillariesSinusoidsSinusoids

11 ) )Present allover the bodyPresent allover the body11 ) )Present in liver , spleen, bone Present in liver , spleen, bone marrowmarrow..

22 ) )Having narrow regular lumensHaving narrow regular lumens..22 ) )Having wider irregular lumensHaving wider irregular lumens..

33 ) )Their walls are formed of simple Their walls are formed of simple squamous cells & are surrounded by squamous cells & are surrounded by

continuous basement membranecontinuous basement membrane..

33 ) )Their walls are lined by fenestrated Their walls are lined by fenestrated cells & are surrounded by reticular cells & are surrounded by reticular

C.TC.T..

44 ) )Their walls have no pores except in Their walls have no pores except in kidney & endocrine glandskidney & endocrine glands..

44 ) )Their walls contain poresTheir walls contain pores..

55 ) )Undifferentiated pericyte cells are Undifferentiated pericyte cells are present in their wallspresent in their walls..

55 ) )Phagocytic macrophage littoral Phagocytic macrophage littoral cells are present outsides their wallscells are present outsides their walls..

The red pulpThe red pulp

--soft tissue present between the white soft tissue present between the white pulps and the blood sinusoidspulps and the blood sinusoids

--It formed of It formed of lymphocytes,erthrocytes,leukocytes&plaslymphocytes,erthrocytes,leukocytes&plasm cellsm cellsIt is rich on phagocytic cells as: It is rich on phagocytic cells as: histiocytes,mononucytes&fixed histiocytes,mononucytes&fixed macrophagesmacrophages

Blood circulation in the SpleenBlood circulation in the Spleen

The splenic artery arise from the coeliac The splenic artery arise from the coeliac artery it enters the spleen at its hilumartery it enters the spleen at its hilum

Function of SpleenFunction of Spleen

11--blood cells are formed in the spleen blood cells are formed in the spleen during foetal lifeduring foetal life

22--Stores blood cells&blood platelets in Stores blood cells&blood platelets in adultsadults

33--contracts to pour blood to the circulation contracts to pour blood to the circulation during hemorrhageduring hemorrhage

44--splenic macrophages filter the blood splenic macrophages filter the blood from bacteria&foreign bodiesfrom bacteria&foreign bodies

55--splenic macrophages phagocytose the splenic macrophages phagocytose the destructed blood cellsdestructed blood cells

66--splenic macrophages can store ironsplenic macrophages can store iron

77--spleen has humoral&cell mediated spleen has humoral&cell mediated immunological functionsimmunological functions

Differences between lymph nodes & SpleenDifferences between lymph nodes & Spleen Lymph nodesLymph nodes SpleenSpleen

11--multiple , present in groups all over the bodymultiple , present in groups all over the body

22--Filter the lymphFilter the lymph

33--Have many afferent & efferent lymph vesselsHave many afferent & efferent lymph vessels

44--Covered with fasciaCovered with fascia..

55--Capsule is thin , & not adherentCapsule is thin , & not adherent

66 - -Trabeculae are thin , short & arise from the Trabeculae are thin , short & arise from the capsulecapsule

77 - -Lymphatic nodules are arranged into cortex & Lymphatic nodules are arranged into cortex & medullamedulla. .

88--In the cortex there are the lymphatic nodules with In the cortex there are the lymphatic nodules with apparent germinal centers but with no central apparent germinal centers but with no central arteriolesarterioles..

99 - -Presence of cortical & medullary lymphatic Presence of cortical & medullary lymphatic sinusessinuses..

1010 - -Presence of medullary lymphatic cordsPresence of medullary lymphatic cords

1111 - -Cells : are mainly lymphocytes , plasma cells & Cells : are mainly lymphocytes , plasma cells & macrophagesmacrophages..

1212 - -Functions : Humoral & cell –mediated Functions : Humoral & cell –mediated immunological functionsimmunological functions..

11 - -A single organ present in the abdomenA single organ present in the abdomen

22--Filters the bloodFilters the blood

33 - -Has few lymph vessels in the capsule & trabeculaeHas few lymph vessels in the capsule & trabeculae

44 - -covered with peritoneumcovered with peritoneum. .

55 - -Capsule is partially thick , adherent & rich in Capsule is partially thick , adherent & rich in smooth musclessmooth muscles..

66 - -Trabeculae are thick , long & arise from the hilum Trabeculae are thick , long & arise from the hilum & from the capsule& from the capsule

77 - -Lymphatic tissues are white & the red pulps ( not Lymphatic tissues are white & the red pulps ( not arranged in cortex & medullaarranged in cortex & medulla..

88 - -The white pulps are scattered in the spleen. They The white pulps are scattered in the spleen. They contain central arterioles but their germinal centers contain central arterioles but their germinal centers are not apparentare not apparent..

99 - -Presence of blood sinusoids all over the spleenPresence of blood sinusoids all over the spleen..

1010 - -Presence of Billroth cords or red pulpsPresence of Billroth cords or red pulps. .

1111--cells : are mainly RBCs, leucocytes , plasma cells cells : are mainly RBCs, leucocytes , plasma cells & macrophages& macrophages..

1212 - -Functions : Blood storage & immunological Functions : Blood storage & immunological functionsfunctions..

TonsilTonsil

11--The palatine tonsilThe palatine tonsilThose are two masses of lymphatic tissue Those are two masses of lymphatic tissue of under the mucous membrane of the oral of under the mucous membrane of the oral part the pharynxpart the pharynxTonsil is covered with Non-Keratinized Tonsil is covered with Non-Keratinized stratified sq. epithelium underlying stratified sq. epithelium underlying lymphatic tissue to form lymphatic tissue to form primary&secondary cryptsprimary&secondary crypts

The Lymphatic tonsils consist of the The Lymphatic tonsils consist of the followingfollowing

11--lymphatic nodules with or without lymphatic nodules with or without germinal centersgerminal centers

22--Diffuse lymphatic tissue:formed of Diffuse lymphatic tissue:formed of lymphocytes,plasm cells,macrophageslymphocytes,plasm cells,macrophages

33--mucous glands are present in the C.T.of mucous glands are present in the C.T.of the tonsils but their ducts do not open into the tonsils but their ducts do not open into their cryptstheir crypts

33--The lingual tonsilThe lingual tonsil

Collections of lymphatic nodule in the Collections of lymphatic nodule in the C.T.under the tongueC.T.under the tongue

Ducts of the underlying mucous gland Ducts of the underlying mucous gland open into these cryptsopen into these crypts

Their secretion wash bacteria&debrisTheir secretion wash bacteria&debris

Infection is not common in the lingual Infection is not common in the lingual tonsiltonsil

44--The Tubal TonsilThe Tubal Tonsil

These are 2 masses of lymphoid tissue These are 2 masses of lymphoid tissue present in nasopharynx around thepresent in nasopharynx around the

Eustachian opening of the Eustachian Eustachian opening of the Eustachian tubestubes

The inflammatory cells may migrate the The inflammatory cells may migrate the medille ear causing otitis mediamedille ear causing otitis media

Function of the TonsilsFunction of the Tonsils

Form antibodies&lymphoytesForm antibodies&lymphoytes

Defence against infectionsDefence against infections

22--The Pharyngeal tonsil or the The Pharyngeal tonsil or the adenoidadenoid

Consist of single mass of diffuse lymphatic Consist of single mass of diffuse lymphatic tissuetissue

Present in the nasopharynxPresent in the nasopharynx

Structures similar to palatine tonsilStructures similar to palatine tonsil

It covered by pseudo-stratified columnar It covered by pseudo-stratified columnar ciliated epithelium achild who has an ciliated epithelium achild who has an enlarged pharyngeal tonsilenlarged pharyngeal tonsil

Tonsil, human - H&ETonsil, human - H&E