Histology Epithelium PDF

I t,F" I! lstYeor r+. rl l: tI 1) t 0 fi r &evetropxmexat; Originate from 3 embryonic genn ceil iayr:rs:...

I t,F" I! lstYeor r+. rl l: tI 1) t 0 fi r &evetropxmexat; Originate from 3 embryonic genn ceil iayr:rs: a- Ectodern e.g.: epithelium of skin. b- Endodefin e.g.: epithelium of GIT, liver & Panmeas. c- mesodeftn e.g.: epithelium of urinary systern. j) t v Gemeral charactea's of' epitheliuns: 1- Epithelial cells are close togettrer with little or no intracellular substance. i i 2- Celljunctions are present between epithelial cells to help their fixation. 3- It's separated from the underlying CT by basernent cr.err llrane..],.=t..t 4- No blood vessels (not vascularized). 'l 5- No lymph vessels. I I 7 6- It has nerye endings. I i 7- Epithelial cells receive their nukition from underlying CT by diffuse. cJ 8- Epithelial cells have high powff to regenelare after degeneration. I iE: 9- Epithelial cells show polari.v. ;_fl 4  v Ciassifficarion o'f epi.fheliurrn : - Surface epithelium. - Glandular epithelium. - Myoepithelium. - Neuroepithelium. Surface Epithetium v Definition: r-+ It's the lining epithelium of the tubes & cavities. I I ,Ir', the covering epithelium of the body surface. v Classification: Simple & Stratified: according to the nurnber of layer. [Al Simple epithelium ' It's a surface epithelium in which the cells are arrangecl ,.e o::.e layer. ' According to the shapq of the cell of this layer, it's classified into: Epithelial TiEsue l I j -t I 5imptre Cuhoidal :I J Simple $qnarnous iI ) J 1 Simple Columnar Stratified Squannous  I I TstYetr nl Single layer offfat c.il- Single layer of :.\ \ike L(T"p \op Vievl vievj sg,i J[c) ,cubfcal cell -> Acidophilic,wirh: i Acidophilic or Acidbphdc, oi Basophilic Basophilic - Few organelles. according to,activity I 1- Thyroid follicles. - Simple col.lV.irhoui >$ood vessels,,r8lg -1h, Vt 2- Renal tubule,. brush boarder r, l.J*(endothelium). I 3- Ovarian surface. e.g. stomac&. '!treura, pericardium - Sirnple col. \Vith peritoneu.. _1-.: brush boarder. Selo*s L,r,; n3 Gt 2 r,rt€SdheL;u^ bY EM:. '. ,r, Bow^ en:, c5 g5u{u - oilia: e.g. fallopian, tube" )8. us - Microvilli: e.g. small intestine. Provide smoo,th & thin Absorption -Secretion: stomach. -! surface to help -> & Secretion. J 1 I -Absorption: small filtration & diffusion of ) intestine. 1 , I water, electrolytes & -Movement: fallopian gases. ii tube to help sperm ) & ova. i l EJ  fl 7rr v"o, I Shape: One sheet of cell in which: - All cell rest on the basement rnernbrane (simple). - However, sorne cells are tall with apical nuclei & other cell are shg4 with basal nuclei (appearance of stratified). (i site : - c iriateci - " it*n ciliated r.r,^*:fi;lr;* {t;[i{, e.{.1arge ducts of glands. :ur{!s.l-*jt$ti.# - Sierer:citia e.g. epididymi s.. r pte.*d.o s.17*,F,'"A c.t- ,p;1h ' ,;lh v!oy--^i;N' "'i,i?J('t"'*.i t, 1 a r s:B$-+\ Function: Protection or according to its site. "1{d. It's a surface epithelium in which the cells are illrangecl ,,t i;r:,ver&l la1ier:;.. The basai layer is formed of columnar cells. The middle layers are forrned ofpolyhedral cells. The superflciai layer have different shape. F unctiora: All types of stratified epithelium perform prc' r; ;;t i 1, c f-unctir;,n, so they are found in the surfaces subjected to Friction.. T)'pes: -ir T.t \s c\ass,Fie\ accorJ; n1a,- ftrnt tL"g'- '? fht -o't I i ,. I S$f erFi cl>\ ce\\s l 1- Stratitled squarnous; I l -+ The superficial cells are fiat. l -+ Site: i l a- lrion i eratinized St. Sq. epithelium. E.g. epithelium of mouth, pharynx, l 1 esophazus & anal canal (wet). b- Ker::iiniz*rl St. Sq. epitheliurn. E.g. epidermis of skin (dry). (Tough, resist friction, impermeable to water & formed of dead cells). ( P'i\utro"\ ( gttu"ff '^.,f," \ors)  1st Ycar 2- Srratitied cuboidal: --+ The superficial cells are cuboidal. f, + Site: Large ducts of exocrine glands as salivary glands. * \*&.f =*u* dyr"\ 3- Stratified colurnnar: -+ The superficial cells are columnar. -+ Site: a- Irlon ciliated St. col. Epithelium e.g. large ducts of exocrine glands & penile part of male Urethra. b- Ciliated St. col. epithelium. e.g. fetal esophagus. 4- Transitional epitheliurn: na1 bc -+ The superficial cells are cuboidal &*Binucleated. or Aorne Il\(. -+ Site: only in renal pelvis, ureter, u.B. 1't part of urethra. ( sTr.t h ab\e orgr* -+ When urinary bladder is ernpt-r:.1-3 ia:rers of cells. & when urinary bladder is il: ,l-.] l;r',iers of cells. I t "J + B>el a tl is rnacle up , F crbo;d>l Cells. Lrye. 1 I I *',,frr^.d-l# b1e, is ynade uf.F pJlhni..ra! &11t. i tl t. :Ie S g"ci$.z"\.f$"&'.rr.r.. l l d I I- f-4\o. $\.\,\.rrn ^t rl 1. 2- IVe,,rr'" ep;lhe i ir/ tr1 r -l-tl zJ- 1 :l e lht Ir'u rn 1. Grrmina 9i ,. : Definition: Epithelial cells which have the ability to conrrrcl lii..e muscte as these cells t- contain n:1rofi1a,raenis. ( rich r ,,. );ff^ 4, w,{ o 5 in f ,lr*rn"t Sitet befween the secretory cells of exocrine gland & their basal lamina ( Surrou J. \. ", ;eci{"1}ci\(i e,g. salivary & sweat glands.2g rteylt mArX 3!a"A - Function: heip releasing secretory products to the lumen of the acini. thrl a,',Errl >d slueeze the aun; fi suurle il'ro-;. s"rnefrr. Definition: Moditied epithelial cells for percepticn of nerve stimuli. Site:: 1- Tongue: taste buds..i_,Sl 2- Inner e*r: Organ of corti. e""-11 3- Nose: Oifactory mucosa. r":i!. lrttto€Piil',el;tl Glls acl as ^ sens or"{ rercffrs F "n 1-+-! SPeu')i 5iintrl,' t !l- ,Pf ' -f[. 11€rt(o, pllfr, {.al {* llt Grrl haf , te tt or1 u[J f ret 3ur {a{e '. th, bas"s " F nettroeTilh-lrJ c*\\ trt s \s 5vr{om J.J btr sonsor! nLr{e - 5- 6ern;ne{ eP1thet;u^ -> fi: in ftri;t C ovarl  Det'inition: group of epithelial cells which have been specialized for secretion. Ileveloprnent: the gland is formed by invaginatiou of surface epithelium which may 1- Remain connected to the surface epithelium with a duct to form (t:xocrine gland). 2- Not connected to the surface to form.(entJor:rine gla:r.,C). Types: (According to the presence or absence of duct system): a- Exocrine gtrand: secrete their products through a ducr;. e.g. salivary & sweat glands. b- Endocrine gland: in: bk:od e.g. thyroid gland. secrete their products (hormones) directly c- &Iixed gtand: contain endocrine & exocrine potion e.g. pancreas, i'ir'{ j lfti: ,. 1- Nature of, secretion: a- Mucous gland: secrete viscous mucous e.g. goblet cells. b- Serous glarad: secrete protein rich watery fluid e.g. parotid gland. c- Sero,mu'cous glanrl: secrete both serous & mucous e.g. submandibular gland. it J d-Other: 1 - Fatty secretion: sebaceous gland. tI - Waxy secretion: ceruminous gland. (external ear) - Cellular secretion: Testis & ovary. rl$ ",& ^ U..o r*,r -{@rt EI EIIJ ,u,$1 4"r ls \+t7 t 1'.,*.'- \ r-L"-l / 1,**,. ', f-'-'--=-t. i ,fi :1, ::-{ i ', ,.ffi "r1 ^ , l,sl:i ,:q {, l! I 1.hr i'k,1r I 't'1, j6 I.-." ; {*ii : Dyinq i -';; I #t i i '..--. i \ !{[E]f,tlr , I 1. Illt: T-tl' ' l',-..i l-*--*- -*' ;. ,0.pr+rine Hcitr'xr,,ne  I lstYear T 2- Mlechamisrn of secretion: a- fotero- crime: The gland release their secretion by exocytosis without any cellular lo change e.g. parotid gland. b- Airo- crtne: The apex of the cell is released with the secretion. ( &.Ts*te\.t*J.urs") e.g. mammary gland. c- Ho[o- criure: The cell become (bloated) with secretory product. Then, cell ruptures to release its content.e.g. sebaceous gland. 3- Numrber of cells: a- Umfrcellunnr g{and: goblet ce}.t (3S + F) I $hape: Cup like as its apex is expanded with secretory granules & it's base contains flat nucleus & some organelles. Staining: With H&E the mucin is dissolved & the cells apf'ear vacuolated so, special stain (PAS) is used. Site: Epithelial lining of respiratory tract, intestine. flunction: Secretion of mucous. ,ll Mucin Golgi apparatus '=i Nucleus I i.j b- Ululticellutrar giand: they are classified according to: Mucous cell 1- The shape of secretorv portion: - Tubular gland - Alveolar or acinar gland. - Tuboalveolar gland. 2- The shape of duct portion: - Simple: have a single unbranched duct. 1 - Compound: have a branched duct.  Examples of types, shapes and sites of some glands I Shape of secrbdpry &iaurl$ ilil ii; rj i , : i:;. si (ds , i, portiofoiil: iig idi,. ll ,i'. ' tl) Simple tubular -Straight tubular secretory portion. Intestinal crypts - Unbranched duct. Simple coiled -Coiled tubular secretory tubular portion Sweat glands - Unbranched duct Simple branched -Branched fubular secretory tubular porlion. Fundic glands of the stomach. ,' - Unbranched duct '--1 i I t\ ",'. , lrq i-1'. I Simple alveolar - Sac- like secretory portion. Paraurethral - Unbranched duct. glands Simple branched -Branched sac- like secretory alveolar portion Sebaceous gland - Unbranched duct. Simple tubule- -Tubular secretory portion ends alveoldr by sac like dilatation. Brunner's glands - LJnbranched duct Simple branched -Branched tubular secretory tubule-alveolar portion ends by sacs like Minor salivary diiatation. glands { J - Unbranched duct. Compound - Tubular secretory portion tubular Kidney and liver - Branched duct :i ,r': " t Compound - Sac like secretory portion. alveolar Mammary gland - Branched duct Compound -Tubular secretory portion ends Major salivary E;' fubule-alveolar by sac like dilatation. glands and - Branched duct. pancreas  lsalnqnf sEa]3uPd i suolalurutJE) stslsal s66EssBd i lurl-!As dnrl3,lpojdal aiEui l.ri SpuS:fi lSJr.tls.tnOqirrA souElfi rLgArlBS r SP uPl fi,IllEujulB !1,1 rll{lorL url SpuB:6 sito3nH ^'saydu8rsf I rsa/dtuPx;f issid{r6xl HV-lO3/nVOlnEn]- , (uvNtrv) HfiN8NI oNoodnoS H\no3/frv ollnodruoc oHnodwoS sqNV'IO ONnOd9IOC. 5pu8lts lunuBilir I rt 'enEuol F-sJUArq AtdUJrs.lo '5r:i:,rqdc,s6 ic iuqDlreqan.;puBl6 , $6rudoF[ p ur 36€ls i']o!nW :i:-: lB16 spuel6 1o gd,itc) llo) snoBoEqBS I g:llnpa ui Ftrno, iot\l ;;)uPlE ri.]l1';9s ,J€,trs surrSoJ6t l spust6 leurtselul :s6ldu.,5.YJ :so/di!rsY7 :salduJar?.'s6/druery :se1duex3 H1fTO3AIV (HVHtCv) uv]n8ru. E\nn8ru. ilnn8nr gSHCNVHE3'IdtrilS U\no1 ]v 3'Idwts o3HSNVUA:ndfl\[S ; o3lroC IldWlS :ndnls ,:ill-: ':I:. :i.,1 soNv]c fld$ils.p.nror€r n!6u \1,.a r4.'Do) t H-dpr9rN ala n,t ,arZll tq6'rid6)[v rBlRqnl lsuicaolnqnl *e* j - rEUPE rrlnqnl rgnqrt r"lnqfil paqcuerq JtdurS peucu!,o iduE poltm atdutS BEUrS ${? n (Cell membrane ? Epithelial cells are called polanzedcells as we can distinpuish their different surfaces with (specific st"r'r-,ctural mcciilications) in their apical, lateral & basal membranes. V This specific structure are morpiiologic adattariorts ibr r-i:rliiic functions. &etimitiCIm: Cell mernbrane specialization found on the r,J:'icrtl surfacc of epithelial ceil. N.B.: apical: free. A- jl,ficrsvilii Definition: They are flnger like projections from the apical surface of cell membrane. Site: Small intestine & proxirnal convoluteci tubules of the kidney. I-,WI: Acidophilic brusir border. Actin filament E,M: Fimbrin and villir Binding to. 2 lrm long & BCI nm in diameter. cell membrane. It's center contains 25-30 actin filaments. Binding to cell membrane Actin lilarnsnt. These actin filaments are Sulrounded by the cell membrane. -l i =J. The tip of the actin filaments are attached to 1 the covering cell membrane while the bas*s -'-*1,;'y1>/Ee -.Lr>^, F6Io- ( Lrije