PRACTICA HISTOLOGIADIGESTIVO I - II - IIIDR. MARION. CASTRO RACCHUMIDR. WALTER ESPINO SAAVEDRADR.ORLANDO VELASCO VELADR. LIDO ZAMBRANO ACUA

APARATO DIGESTIVO

CAVIDAD ORAL

LABIOSSUPERFICIE EXTERNA

LABIOSBERMELLON

LABIOSCARA INTERNA

PALADAR DUROEPITELIO PLANO ESTRATIFICADO QUERATINIZADO O PARAQUERATINIZADO

PALADAR DUROEPITELIO PLANO ESTRATIFICADO QUERATINIZADO O PARAQUERATINIZADO

PALADAR DUROEPITELIO PLANO ESTRATIFICADO QUERATINIZADO O PARAQUERATINIZADO

PALADAR BLANDOEPITELIO PLANO ESTRATIFICADO NO QUERATINIZADO

PALADAR BLANDO EPITELIO PLANO ESTRATIFICADO NO QUERATINIZADO

SUPERFICIE DORSAL DE LA LENGUA

ESQUEMA DE LA ESTRUTURA BASICA DE UNA GLANDULA SALIVAL Conducto intercalarConducto estriadoCavidad oralConducto excretorAcino

CONDUCTO INTERCALADOLas clulas del conducto intercalado (flecha)son mas pequeas en comparasion a las celulas acinares y son cuboidales con citoplasma palido y nucleo central.Es evidente un lumen pequeo

Conducto estriadoEl conducto estriado es mas grande que un acino y mucho mas grande que un conducto intercalado.Las clulas son columnares eosinofilicas con ncleo central y citoplasma con estriaciones verticales debido a pliegues de la membrana plasmtica. clulas cuboides a cilindricas bajas.Las membranas celulares basolaterales de estas clulas tienen ATP-asa de Na+ que bombea sodio fuera de la clula al tejido conectivo y de ese modo conserva el sodio.

CONDUCTO INTERLOBULAREsta cubierto por un epitelio columnar pseudostratificado y rodeado de un denso tejido conectivo fibroso.

ACINOS+ CONDUCTOS INTERCALARES+CONDUCTOS ESTRIADOSADENOMEROO SALIVN(unidad funcional de la glndula)

GLANDULA PAROTIDALa glndula salival ms grande,Pesa alrededor de 20 a 30 g Produce alrededor de 30% de la cantidad total de saliva.

Acino seroso

Elabora una secrecin serosa puraSu secrecin tiene concentraciones altas de enzima amilasa salival (ptialina) e IgA secretoria. La amilasa salival se encarga de digerir la mayor parte del almidn en el alimento y esta digestin contina en el estmago hasta que el quimo cido inactiva la enzima. La IgA secretoria inactiva antgenos localizados en la cavidad bucal.

GLANDULA PAROTIDA

ParotidaConducto excretor con epitelio columnar seudoestratificadoEl conducto excretor principal o conducto de Stenon o parotideo, desemboca a nivel del primer molar superior.

GLNDULA SUBMAXILAR

Pesa 2 a 15 g.

Elabora cerca de 60% de la produccin total de saliva. Casi 90% de los cinos produce saliva serosa, en tanto que los cinos restantes elaboran saliva mucosa.

El nmero de semilunas serosas es limitado. (semiluna de gianuzzi)

Conducto estriadoLos conductos estriados de las glndulas submaxilares son mucho ms largos que los de las glndulas partidas o sublinguales.Conducto estriado

GLNDULA SUBLINGUALES

Es la ms pequea de las tres glndulas salivales mayores. Tiene forma de almendra,Pesa 2 a 3 g Elabora apenas 5% de la produccin total de saliva.

La glndula est compuesta de unidades secretorias tubulares mucosas recubiertas por semilunas serosas La glndula sublingual produce saliva mixta, pero sobre todo mucosa. Entre las clulas de moco de las unidades secretorias se encuentran canalculos intercelulares bien desarrollados. Las glndulas sublinguales tienen una cpsula de tejido conectivo escasa y su sistema de conductos no forma un conducto terminal. En lugar de ello, varios conductos se abren en el piso de la boca y en el conducto de la glndula submaxilar.

Glandulas salivales menores

La cavidad oral contiene una gran cantidad de tejido glandular salival diseminado difusamente por la submucosa.Glndulas linguales en la submucosa y las capas musculares de la superficie dorsal de la lengua.Glndulas sublinguales menores cercanas a las glndulas sublinguales principales(existen otras glndulas linguales en la superficie inferior de la punta de la lengua y en sus bordes laterales)Glndulas labiales en la superficie interna de los labios.Glndulas paltinas en la submucosa de los paladares blandos y duros.Glndulas amigdalinas en la mucosa asociada con las amgdalas palatina y farngea.Glndulas bucales en la submucosa que tapiza las mejillas.

Las glndulas labiales,sublinguales,linguales menores y bucales estn formadas principalmente por clulas mucosas aunque puede haber algunas clulas serosas.

Las glndulas palatinas y linguales laterales son totalmente secretoras de moco.

ESFAGO:E=epitelio escamoso estratificado no queratinizado (0.5 mm de grosor)LP=Lamina propiaS=submucosaIC=circular internaOL=longitudinal externa

ESFAGO:La clula basal del epitelio alcanza la superficie libre en aproximadamente tres semanas.

Glndulas submucosas:SeromucosasClulas serosas:Pepsinogeno,Lisozima.

Musculo EstriadoMusculo Liso

El estomago posee 4 regiones:Cardias (desde la linez Z y mide aprox 2 cm)FondoCuerpoAntro pilricoEl estomago tiene un volumen de 50 ml a 1500 mlLas caractersticas histolgicas del fondo y del cuerpo son idnticas.

MUCOSA GASTRICA(FUNDICA)

MUCOSA GASTRICA(FUNDICA)

MUCOSA GASTRICA(FUNDICA)

GLNDULAS FNDICASIstmoCuelloBase(+larga)123456

Clulas parietales y principales

Clulas parietalesClulas principalesClulas parietales(Oxnticas)HCl Factor intrnseco gstrico: glucoproteina que es necesaria para la absorcin de vitamina B12 en leonClulas principales(Cimogenas)Contienen pepsinogeno (Renina,Lipasa gstrica).Vago secrecinSecretina secrecin

Clulas parietalesClulas principales

MUCOSA GASTRICA (ANTRAL):Similar a la mucosa cardiacaFoveolas mas superficialesPresenta mas clulas mucosas del cuello

MUCOSA GASTRICA (ANTRAL)

MUCOSA GASTRICA PILORICAFOVEOLAS MAS PROFUNDAS

INTESTINO DELGADO

VELLOSIDADES

Microvellosidades (borde en cepillo)

LA MUCOSA Y LA SUBMUCOSA SE SITAN POR ENCIMA DE LA MUSCULAR FORMANDO PLIEGUES, LLAMADOS PLICAE CIRCULARIS (PLIEGUES CIRCULARES) O VLVULAS DE KERCKRINGSUBMUCOSASUBMUCOSAMUCOSA

Plicae circularis (pliegues circulares) o vlvulas de KerckringPLICA CIRCULARISVELLOSIDADESVELLOSIDADESCELULAS CALICIFORMES

PC - PLICA CIRCULARIS;SM SUBMUCOSA; CML - CIRCULAR MUSCLE LAYER; LML - LONGITUDINAL MUSCLE LAYER; AMC - AUERBACH'S MYENTERIC PLEXUS; V - VILLI; BV - BLOOD VESSELS; S - SEROSA; MM - MUSCULARIS MUCOSAE; IG - INTESTINAL GLANDS

PLIEGUES CIRCULARES

MUCOSA DEL INTESTINO DELGADO:Epitelio y lmina propia

Clulas de absorcin de la superficie Clulas caliciformes

MUCOSA DEL INTESTINO DELGADO:Epitelio y lmina propia

Placas de peyer:Lmina propia del leon

Placas de peyer:Lmina propia del leon

CRIPTAS DE LIBERKUHN:Presencia de clulas de paneth (viven 20 dias)Estan en el fondo de las criptas y secretan:lisozima,defensinas,FNT alfaClulas de paneth

CELULASDE PANETH

DUODENO:GLNDULAS DE BRUNNER

GLNDULAS DE BRUNNER Las glndulas de brunner secretan un lquido alcalino y mucoso (x estimulacin parasimptica) que neutraliza el quimo cido.

UROGASTRONA (factor de crecimiento epidrmico humano):suprime la produccin de HCl y aumenta la actividad mittica de las clulas.

Las glndulas se pueden extender hacia la mucosa

Plexo submucoso de meissner

Plexo submucoso de meissner

Plexo mienterico de Auerbach

YEYUNO

LEON

INTESTINO GRUESO

1234HISTOLOGIA DEL COLONNo vellosidadesCriptas de lieberkuhnLmina propia , muscularis mucosae y submucosa similar a IDClulas de absorcin (son las ms numerosas)Clulas Caliciformes (aumentan del ciego al colon sigmoide)Clulas regenerativas(regeneran el epitelio en 6 a 7 das)Clulas enteroendocrina

Muscular externa: La LE forma tres listones tenias del colonhaustras del colonSerosa: apndices epiploicos

COLON G:clulas caliciformesO:criptas de liberkuhn

Criptas de liberkuhn E:clulas SDNEL:Luz de criptaP:celula plasmtica

COLONSUBMUCOSACRIPTA DE LIEBERKUHNMuscular de la mucosaLmina propia

Mucosa colnica

HGADOHEPATOCITOFUNCIN EXOCRINAFUNCIN ENDOCRINAHgado pesa alrededor de 1500 g

HEPATOCITOS MONO Y BINUCLEADOS

HEPATOCITOS MONO Y BINUCLEADOS:hepatocitos tienen una vida aproximada de 150 das

CORDONES DE HEPATOCITOS O TRABCULAS DE REMAK

Los hepatocitos poseen tres superficies:Superficie sinusoidal (70%)Superficie canalicular(15%)Superficie intercelular (basolateral)(15%)

Sinusoides con endotelio fenestrado (flecha curva) y no tiene lamina basal.Los hepatocitos forman las paredes de los canalculos biliares (flechas delgadas),se observa una clula de kupffer

SANGRE OXIGENADA (25%)Arteria heptica derecha e izquierda SANGRE VENOSA RICA EN NUTRIENTES (75%)Vena portaSinusoidesVena central O Vena terminalVena sublobulillarVenas colectorasVenas hepticas derecha e izquierda

El hgado posee escaso componente conjuntivo pero aumenta en los espacios porta

Espacios porta (areas portales o triadas portales

Espacios portaSe puede encontrar algunos linfocitos, macrofagos,mastocitos PERO NO POLIMORFONUCLEARES O CELULAS PLASMATICAS

Arquitectura microscpica del hgadoLobulillo heptico ClsicoLobulillo portalAcino heptico(acino de rappaport)

Hgado de cerdo mostrando configuracin hexagonal

Lobulillo heptico Clsico

Lobulillo hepticoVena central y espacios porta.

VENA CENTRAL(LOBULILLO HEPATICO)

Vena central o vena terminal

Vena terminal o central y sinusoides hepticos

Sinusoides con endotelio fenestrado (flecha curva) y no tiene lamina basal, los hepatocitos forman las paredes de los canalculos biliares (flechas delgadas),se observa una clula de kupffer

Macrfagos con partculas de carbn

Espacios porta Conducto biliar Interlobulillar Con epitelio cubico o cilndrico bajo

PNCREASPncreas endocrinoPncreas exocrinoClulas acinosas que sintetizan 1500 ml de jugo pancretico/daClulas de los Islotes de langerhans

Tabiques de tejido conectivoTejido endocrino (islotes de langerhans)(1% del peso de la glndula)Tejido exocrino (acinos)

PNCREAS EXOCRINO

En la parte apical presenta grnulos de secrecin o grnulos de zimgeno (eosinofilos)(proenzimas)Tejido acinoso

Los acinos son redondos u ovales y se componen de clulas epiteliales piramidales,cuyo pice se orienta hacia la luz central. Nucleos redondos,basales y las clulas son muy basfilas.

CONDUCTOS INTERCALARES (epitelio simple cubico o cilindrico bajo)Sistema de conductos excretores

Acinos y Clulas centroacinares(flechas)

Tejido acinoso: clula centroacinar

Pncreas exocrino-Conductos interlobulares (interlobulillares) rodeado de gran cantidad de tejido conectivo.Los conductos intercalares se vacan en los conductos interlobulares (epitelio cilindrico simple)

Conductos intercalaresConductos IntralobulillaresConducto pancratico mayor o de Wirsung (epitelio simple cilindrico alto) Conducto pancratico menor o de santorini (epitelio simple cilindrico alto) Conducto de Wirsung Celulas centroacinaresConductos Interlobulillares

PNCREAS ENDOCRINO

Islote de Langerhans

Islotes de langerhansClulas A (alfa)20%Clulas B (beta)70%Clulas D (delta)5-10%Clulas F1%GLUCAGNINSULINASOMATOSTATINAPOLIPPTIDO PANCREATICOClulas G1%GASTRINA

Clulas (A) secretoras de GlucagnClulas (B) secretoras de InsulinaClulas (D) secretoras de SomastostainaClulas (F) secretoras de Polipptido pancretico

*The muscularis externa consists of skeletal muscle in the proximal (upper) third of the esophagus and smooth muscle in the distal third. This micrograph shows a transitional region in which both types of muscle are present.

In this figure, a small amount of connective tissue occupies the spaces between muscle fibers. In addition to the large mass of smooth muscle in the lower half of the figure, some inconspicuous small bundles of smooth muscle may be seen near the top center and the upper right (indicated by blue arrows).

The appearance, or visual texture, of muscle varies dramatically depending on the orientation of the fibers with respect to the plane of section. All of the muscle fibers in this view are cut in cross section.

Individual smooth muscle fibers are usually difficult to resolve, even at fairly high magnification. Cross-sectioned smooth muscle displays only scattered nuclei. In each individual fiber, the nucleus occupies only a small fraction of the fiber's length. So nuclei appear only in a similarly small proportion of the fibers cut by any single section. (Remember, each smooth muscle is a single cell, each with its own nucleus.)

Individual striated muscle fibers are conspicuous as individual units. Each fiber has so many nuclei that any random cross section typically displays at least one and often several, normally located around the periphery of the fiber.

*The stomach, the most dilated region of the alimentary canal, is a sac-like structure that in the average adult can accommodate approximately 1500 ml of food and gastric juices at maximal distention. The bolus passes through the gastroesophageal junction into the stomach, where it is processed into a viscous fluid known as chyme. Intermittently, the stomach empties small aliquots of its contents through the pyloric valve into the duodenum. The stomach liquefies the food, continuing its digestion via the production of hydrochloric acid and the enzymes pepsin, rennin, and gastric lipase and via production of paracrine hormones.The lumen of the fundic stomach is lined by a simple columnar epithelium composed of surface-lining cells, which manufacture a thick mucus layer, known as visible mucus. Surface-lining cells continue into the gastric pits, forming their epithelial lining. Much of the lamina propria is occupied by the 15 million closely packed gastric glands, known as fundic (oxyntic) glands in the fundic region. Each fundic gland extends from the muscularis mucosae to the base of the gastric pit and is lined composed of a simple columnar epithelium consisting of of six cell types: surface lining cells, parietal (oxyntic) cells, regenerative (stem) cells, mucous neck cells, chief (zymogenic) cells, and diffuse neuroendocrine system (DNES) cells.For more information see General Plan of the Digestive Tract in Chapter 17 of Gartner and Hiatt: Color Textbook of Histology, 3rd ed. Philadelphia, W.B. Saunders, 2007.

**The mucosa of the small intestine is lined by simple columnar epithelium which evaginates into villi and invaginates into crypts. Note that epithelium of villi is continuous with that of adjacent crypts, even though some crypts appear "disconnected" due to plane of section.Lamina propria of the small intestine forms the core of villi and surrounds the crypts. A long "empty" space within the lamina propria, especially if lined by simple squamous endothelium, is a lacteal.The muscularis mucosa of the small intestine forms a thin layer (only a few muscle fibers in thickness) beneath the deep ends of the crypts.

**Crypts are a prominent feature of the intestinal mucosa. The columnar epithelium which lines the crypt consists of stem cells and newly-formed absorptive and goblet cells.At the bottom of the crypt are Paneth cells. Each paneth cell has a typical serous cell appearance, with secretory vesicles (bright red in this micrograph) containing lysosomal enzymes packed into apical cytoplasm. (These granules are not conspicuous in most H&E specimens.)The many small nuclei in lamina propria are mostly lymphocytes. (Identifying individual cells in lamina propria is not practical in most routine specimens.)*Duodenal mucosa is typical of the small intestine. The duodenum is distinguished from other regions of the small intestine by the presence of submucosal Brunner's glands. These mucous glands pack the submucosa so completely that the typical submucosal connective tissue is obscured. Muscularis externa of the duodenum has the standard inner circular and outer longitudinal layers of smooth muscle. The pancreas lies near the duodenum and may appear in some of our non-human specimens (particularly on the slide labelled "Small Intestine, Three Regions").

*GLNDULAS DE BRUNER, (caractersticamente 1/3 en la mucosa y 2/3 en la submucosa)

**The muscularis externa consists of smooth muscle fibers arranged into two layers. The layer of circular muscle fibers (cut in longitudinal section) appears at the upper left, while the layer of longitudinal muscle fibers (cut in cross section) appears at lower right.In between the two layers of muscle lies the parasympathetic nerve plexus of Auerbach (also called the myenteric plexus). In routine histological specimens, the ganglia (small clusters of nerve cell bodies) are the only noticeable feature of Auerbach's plexus. Nerve cell bodies are usually rather conspicuous. Each cell body can be quite large (up to ~50m), with relatively basophilic cytoplasm, with a large round euchromatic nucleus, and with a single prominent nucleolus.Associated with peripheral ganglia are numerous small satellite cells and Schwann cells, as well as fibroblasts of the surrounding connective tissue.

**The mucosa of the colon is characterized by straight crypts with no villi.Unless specially stained, the mucus in goblet cells appears as clear "bubbles" in crypt epithelium. But note that epithelial nuclei are more numerous than the mucus blobs, indicating that absorptive cells remain the predominant cell type in colon epithelium (as also in the small intestine), even though they are crowded by goblets and hence inconspicuous.

*Portal areas (also called portal triads or portal canals) are located at the corners of liver lobules. Portal areas are normally surrounded by much larger areas packed with hepatic cords and sinusoids.Each portal area contains three (hence the term portal triad) more-or-less conspicuous tubular structures all wrapped together in connective tissue.a branch of the bile duct a branch of the portal vein a branch of the hepatic artery Of these three, the bile duct is the most easily recognized, by the conspicuous round nuclei in its cuboidal epithelium.(A typical portal area also contains two additional structures, a nerve and alymphatic channel, but these are inapparent in routine specimens.) The portal areas visible in any random section of liver vary widely in the absolute sizes of the vessels and ducts therein.Since the portal vein brings much more blood to the liver than does the hepatic artery, each branch of the portal vein is typically much larger than the associated branch of the hepatic artery. The relative sizes of the paired vessels in a portal area thus differ from those of a typical vein / artery pair in other parts of the body, where the artery delivers the same volume of blood that the vein subsequently returns.An increase in the amount of connective tissue extending out from portal areas is characteristic of cirrhosis (sclerosis / fibrosis / scarring of liver), in which damaged hepatic tissue is replaced by scar tissue (fibrous connective tissue). For images of cirrhosis, see WebPath or Milikowski & Berman's Color Atlas of Basic Histopathology, pp. 284ff.

*This specimen comes from an animal which was injected intravenously with a suspension of carbon particles. These particles are scavenged by macrophages, most notably by those in the liver which are called Kupffer cells., whose cytoplasm becomes packed with black carbon particles.In the absence of such experimental demonstration, Kupffer cells can be recognized by their oval nuclei closely associated with sinusoidal spaces.Endothelial cells appear similar, but with thinner (flatter) and denser nuclei and with less conspicuous cytoplasm.In contrast, the hepatocytes which comprise the hepatic cords have round nuclei surrounded by abundant cytoplasm. The space of Disse is visible here and there on this image, appearing as a thin bright band between hepatocyte cytoplasm and the thinner, darker band which represents the endothelium.*