Connective Connective Tissue(C.T.)Tissue(C.T.)

The mesodermal ………………. to mesenchymal The mesodermal ………………. to mesenchymal tissue(undifferentiated mesenchymal cells&hemogenous tissue(undifferentiated mesenchymal cells&hemogenous intercellular substance of proteinsintercellular substance of proteinsThe mesenchymal tissue are differentiated in the embryo intoThe mesenchymal tissue are differentiated in the embryo into1-connective tissue C.T.1-connective tissue C.T.2-vascular tissue2-vascular tissue3-smooth muscle3-smooth muscle

The connective tissue formed ofThe connective tissue formed of A-C.T. cellsA-C.T. cellsB-C.T. fibersB-C.T. fibersC-C.T.matrixC-C.T.matrix

Types of C.TTypes of C.T..

According to the nature of intercellular According to the nature of intercellular matrixmatrix

we have 3 types of connective tissuewe have 3 types of connective tissue11--C.T. proper( soft matrix)C.T. proper( soft matrix)22--cartilage (rubbery matrix)cartilage (rubbery matrix)

33--Boney ( solid matrix)Boney ( solid matrix)

11--Connective tissue properConnective tissue proper

It is called connective because is It is called connective because is support,binds&connection various support,binds&connection various tissue and organstissue and organs

The C.T. is formed ofThe C.T. is formed of

11--C.T. cellsC.T. cells

22--C.T.fibersC.T.fibers

33--Soft matrix or ground substanceSoft matrix or ground substance

Types of connective tissue properTypes of connective tissue proper

The cells &C.T. fibers are present in theThe cells &C.T. fibers are present in the soft C.Tsoft C.T . .

66) ) SixSix((Types of C.T. ProperTypes of C.T. Proper

11--areolar C.Tareolar C.T..22--yellow elastic C.Tyellow elastic C.T..

33--Mucoid C.TMucoid C.T..44--White collagen C.TWhite collagen C.T..

55--Adipose C.TAdipose C.T..66--Reticular C.TReticular C.T..

Types of Connective tissue cellsTypes of Connective tissue cells

11--Fixed C.T. cells asFixed C.T. cells as

22--Free C.T.CellsFree C.T.Cells

11--Fixed C.T. cells asFixed C.T. cells as::

11--fibroblastfibroblast,, 22--fixed macrophagesfixed macrophages,,

33--fat cellsfat cells , ,44--mesenchymal cellsmesenchymal cells,,

55--pericyte cellspericyte cells,,66--endothelial cellsendothelial cells

77--reticular cellsreticular cells

Fibroblast&Fibrocytes CellsFibroblast&Fibrocytes Cells

--develop from mesenchymal cells&pericytesdevelop from mesenchymal cells&pericytes--It is very numerous in areolar C.TIt is very numerous in areolar C.T..

--basophilic cytoplasmbasophilic cytoplasm--The cytoplasm is rich in The cytoplasm is rich in

RNA,ER,GA,MitochondriaRNA,ER,GA,Mitochondria--fibroblast can dividefibroblast can divide

--Fibroblast can changes into myofibroblastFibroblast can changes into myofibroblast

Function of FibroblastFunction of Fibroblast

- -Form collagen,elastin&reticulin Form collagen,elastin&reticulin substances in order to form C.T.fiberssubstances in order to form C.T.fibers

--Form the mucoprotein of the C.T. matrixForm the mucoprotein of the C.T. matrix increase number during healing of increase number during healing of

woundswoundsFibroblast change into myofibroblast which Fibroblast change into myofibroblast which

close woundsclose wounds

Fibrocytes === mature fibroblastsFibrocytes === mature fibroblasts

- -Small spidle shaped cells with dense Small spidle shaped cells with dense nucleinuclei

- -Acidophilic cytoplasmAcidophilic cytoplasm--can not dividecan not divide

LM of fibroblasts (arrows)

SEM of fibroblasts

22--Fixed macrophages or Fixed macrophages or histocytes cellshistocytes cells

--dervied from blood monocytesdervied from blood monocytes - -more present in the damaged C.Tmore present in the damaged C.T..

--have irregular cell membranehave irregular cell membrane--cytoplasma is not clear-rich in lysosomescytoplasma is not clear-rich in lysosomes

--the nucleus is small ,kidney shapethe nucleus is small ,kidney shape--Histiocytes cells can be stained with vital Histiocytes cells can be stained with vital

stain as stain as trypan bluetrypan blue

FunctionFunction::

--Defence mechanism of the bodyDefence mechanism of the body--can engulf(eat)foreign bodies,bacteria and old can engulf(eat)foreign bodies,bacteria and old

blood cellsblood cells--can clean wound from foreign bodies&debriscan clean wound from foreign bodies&debris

--can transport antigenscan transport antigens--macrophage………multinucleatd gint macrophage………multinucleatd gint

cells…..enclose large foreign bodies in order to cells…..enclose large foreign bodies in order to destroy themdestroy them

33--Adipose cell or fat cells or Adipose cell or fat cells or adipocytesadipocytes

--derived from mesenchymal cellsderived from mesenchymal cells - -flat peripheral nucleusflat peripheral nucleus

--there are 2 types of fat cellsthere are 2 types of fat cells11--unilocular white fat cellsunilocular white fat cells

22--multilocular brown fat cellsmultilocular brown fat cells--Fat cells can not divideFat cells can not divide

StainedStained: : orange with sudan III,black sudan blackorange with sudan III,black sudan black

FunctionFunction

--brown fat responsible for energy brown fat responsible for energy reservoir&heat productionreservoir&heat production

--white fat cells release energy during white fat cells release energy during starvationstarvation

- -support organs as kidneysupport organs as kidney--they act as heat insulatorthey act as heat insulator

44--The Mesenchymal Cells(UMC)The Mesenchymal Cells(UMC)

--embryonic branched cells called(UMC)embryonic branched cells called(UMC)--has large oval nucleus&basophilic has large oval nucleus&basophilic

cytoplasmacytoplasma--present in the embryonic tissuepresent in the embryonic tissue

FunctionFunction::Can differentiate into other types of C.TCan differentiate into other types of C.T..

55--The Pericyte cellsThe Pericyte cells

- - pale branched cells(peri= around)pale branched cells(peri= around)--present immediate external to the present immediate external to the

endothelium of blood vessels endothelium of blood vessels capillaries&small venulescapillaries&small venules

--persistent in adult lifepersistent in adult life

FunctionFunction::

Give rise to both fibroblast&smooth Give rise to both fibroblast&smooth muscle cellsmuscle cells

--role in the process of healing of role in the process of healing of connective tissueconnective tissue

--modified to form myoepithelial cells which modified to form myoepithelial cells which can contractcan contract

66--The Endothelial CellsThe Endothelial Cells

Present in the surface of blood Present in the surface of blood capillaries&blood vesselscapillaries&blood vessels

--develop from the embryonic develop from the embryonic mesenchymal cellsmesenchymal cells

FunctionFunction::

11--synthesise synthesise collagencollagen(type 4 collagen)(type 4 collagen)22--can form the basal lamina of the can form the basal lamina of the

endotheliumendothelium33--divide rapidly ..divide rapidly ..give risegive rise..endothelial cells of ..endothelial cells of

lung capillaries to secret angiotensin lung capillaries to secret angiotensin converting enzymeconverting enzyme

77 - -Reticular CellsReticular Cells

--present in mainly in the reticular C.Tpresent in mainly in the reticular C.T..--modified fibroblast which are specialized modified fibroblast which are specialized

to secrete reticular fibresto secrete reticular fibres--reticular cells are found in the stroma of reticular cells are found in the stroma of

bone marrow,lymph bone marrow,lymph nodes,spleen,liver,pancreasnodes,spleen,liver,pancreas

FunctionFunction::

Supportive&phagocytic cellsSupportive&phagocytic cells--form the stroma of glands&bone marrowform the stroma of glands&bone marrow--removal cellular debris from the lymphatic removal cellular debris from the lymphatic

tissuetissue

22--Free C.T. CellsFree C.T. Cells

11--Mast CellsMast Cells22--Plasma CellsPlasma Cells

33--Free MacrophagesFree Macrophages,,44--Blood LeucocytesBlood Leucocytes55--Melanophore CellsMelanophore Cells

11--Mast CellsMast Cells

22--Histamine secretory mast cellsHistamine secretory mast cellsPresent under mucosa of respiratory Present under mucosa of respiratory

&digestive tract&digestive tractHistamine…………….contract smooth Histamine…………….contract smooth

musclemuscleDilated blood vessels capillariesDilated blood vessels capillaries

Increased the capillary permeabilityIncreased the capillary permeability

--Small cells,round,irregular in shapeSmall cells,round,irregular in shape--present in groups blood vesselspresent in groups blood vessels

Types of mast cellsTypes of mast cells11--Heprin secretory mast cellsHeprin secretory mast cells

Present in the C.T. of skin,secret heprin Present in the C.T. of skin,secret heprin which is an anticoagulantwhich is an anticoagulant

TEM of a Mast Cell

LCT – M = mast cell; P = plasma cells; F = fibroblasts; Eo = eosinophils, N = neutrophils

FunctionFunction::

--Secrete heparin or histamineSecrete heparin or histamine))paracrine cellsparacrine cells((

--release chemical mediators as immediate release chemical mediators as immediate hypersensitivityhypersensitivity

Factors which may cause of anaphylactic Factors which may cause of anaphylactic shockshock

22--Plasma CellsPlasma Cells

PresentPresent peritoneum, submucosa of digestiveperitoneum, submucosa of digestive

respiratory tractrespiratory tract,,lymph nodes&spleenlymph nodes&spleen

--originate from plasmablast cells which develop originate from plasmablast cells which develop from B-lymphocytesfrom B-lymphocytes

--small&round with hemogenous basophilic small&round with hemogenous basophilic cytoplasmcytoplasm

FunctionFunction::

--secrete specific antibodies against secrete specific antibodies against organisms&foreign bodies antibodies organisms&foreign bodies antibodies circulate in the blood termed(humoral circulate in the blood termed(humoral antibodies)&processes is called humoral antibodies)&processes is called humoral immunityimmunity

--Can not divideCan not divide--Have no phagocytic activityHave no phagocytic activity

33--Free MacrophagesFree Macrophages

--derived from blood monocytes after their derived from blood monocytes after their migration to C.Tmigration to C.T..

--their cytoplasma is rich in their cytoplasma is rich in lysosomes&RERlysosomes&RER

--they have oval eccentric nucleithey have oval eccentric nuclei

FunctionFunction::

--Immun system of the bodyImmun system of the body--they are highly phagocytic cellsthey are highly phagocytic cells

--secrete collagenase&elastasa secrete collagenase&elastasa enzymes&lysozomeenzymes&lysozome

--kill certain viruses through secretion of kill certain viruses through secretion of interferoninterferon

44--Bolood LeukocytesBolood Leukocytes

Appear normaly in the C.T.of the Appear normaly in the C.T.of the following body organsfollowing body organs

--Eosinophils&basophilsEosinophils&basophilsFound in C.T. of respiratory Found in C.T. of respiratory

intestinal&female genital tractintestinal&female genital tract--they increase in allergic conditionthey increase in allergic condition

--Lymphocytes&monocytesLymphocytes&monocytesPresent in many organsPresent in many organs

--increased in number in chronic infectionsincreased in number in chronic infections--NeutrophilsNeutrophils::

--They migrate from blood vessels of C.TThey migrate from blood vessels of C.T..--where acute infection is present in order where acute infection is present in order

to phagocytose microorganismto phagocytose microorganism

55--Melanophore pigment cellsMelanophore pigment cells

--They are C.T.macrophages which They are C.T.macrophages which phagocytose melanin Pigments are phagocytose melanin Pigments are formed by the melanocytesformed by the melanocytes

--melanophores are branched cells with melanophores are branched cells with small round nucleismall round nuclei

--melanophore are rich in melanin pigmentsmelanophore are rich in melanin pigments

FunctionFunction::

--They carry melanin pigmentsThey carry melanin pigments

Types of C.T.FibersTypes of C.T.Fibers

There are three(3) types of C.TThere are three(3) types of C.T..11--white collagennous fiberswhite collagennous fibers

22--yellow elastic fibersyellow elastic fibers33--reticular fibersreticular fibers

11--White Collagenous FibersWhite Collagenous Fibers

ShapeShape::colourless wavy branching bundles,the colourless wavy branching bundles,the

fibers run paralled to each otherfibers run paralled to each otherCharcterCharcter::

soft,strong&flexible but not elastic fiberssoft,strong&flexible but not elastic fibers

StructuresStructures::formed of protein known formed of protein known

as(collagen)which can be digested by as(collagen)which can be digested by pepsin&trypsin enzymespepsin&trypsin enzymes

StainingStaining::collagenous fibers are acidophilic,stain collagenous fibers are acidophilic,stain

pink with eosin,red in van-Gison&blue with pink with eosin,red in van-Gison&blue with Mallory stainMallory stain

Types of collagenTypes of collagen

There are five(5) types of collagenThere are five(5) types of collagen11--Type I collagenType I collagen::

PresentPresent:: losse C.T.,White fibro-cartilage,bone&teeth this losse C.T.,White fibro-cartilage,bone&teeth this

type is formed by type is formed by fibroblast,osteoblast,odontoblastfibroblast,osteoblast,odontoblast

22--Type II collagenType II collagen:: hyaline&elastic cartilage&formed by hyaline&elastic cartilage&formed by

chondroblastchondroblast

33--Type III collagenType III collagen : :skin ,smooth muscle&reticular fibers formed by skin ,smooth muscle&reticular fibers formed by

fibroblast&by smooth muscle cellsfibroblast&by smooth muscle cells44--Type IVType IV

collagen: basement membranecollagen: basement membrane of epithelial of epithelial tissue&lenes of eye,It formed by fibroblast&by tissue&lenes of eye,It formed by fibroblast&by endothelial cellsendothelial cells

55--Type V collagenType V collagen:: in placenta,it is formed by fibroblastin placenta,it is formed by fibroblast

22--Elastin fibersElastin fibers

ShapeShape : :fine,straight branching fibersfine,straight branching fibers

CarachterCarachter::the fibers branched&anastomose with the fibers branched&anastomose with

each othereach otherThey run singly&not in bundlesThey run singly&not in bundles

Appear yellow in fresh stateAppear yellow in fresh state

StructuresStructures:: formed of protein known as elastin which formed of protein known as elastin which

is resistant to chemical and to boilingis resistant to chemical and to boilingCan digested by the pancreatic elastase Can digested by the pancreatic elastase

enzymeenzymeStainingStaining::

brown with orcein,black with verhoeff and brown with orcein,black with verhoeff and yellow with van-Gisonyellow with van-Gison

Orecin Stain for Elastin – purple “ribbon candy”

33--Reticular FibersReticular Fibers

ShapeShape:: they are thin,branched anastomose to they are thin,branched anastomose to

form anetwork or reticulumform anetwork or reticulumStrucuresStrucures::

--formed of protein known as collagen type formed of protein known as collagen type IIIIII

--Staining: Black with silverStaining: Black with silver

Sliver Stain for Reticular Fibers

PAS stain of epithelial basement membranes (BM)

TEM of collagen fibers with 64 nm periodicity

TEM of extracellular collagen fibers (Cl)

Masson’s Trichrome Stain – blue = collagen

Areolar Tissue

Pink = collagen

Purple = elastin

TEM of a Plasma Cell

LCT – M = mast cell; P = plasma cells; F = fibroblasts; Eo = eosinophils, N = neutrophils

TEM of a Macrophage