Histology of Digestive System

8/10/2019 Histology of Digestive System

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HISTOLOGY of DIGESTIVE SYSTEM

Ageng Brahmadhi



Overview

GI tract/ alimentary canal

(± 9m in cadaver)

Accescory digestive organs

Mounth

Pharynx

Esophagus

Stomach

Small intestine Large intestine

Teeth

Tounge

Salivary glands

Liver

Gallbladder Pancreas

Digestive system

components:



Overview

Basic process in digestive system: Ingestion

Secretion

Mixing & Propulsion

Motility Digestion

Mechanical

Chemical

Absorption Defecation



Oral Cavity

Lips three regions:

the skin aspect,

the vermilion zone

the mucous aspect.

The mucous (internal) aspect of the lip is always wet and is lined

by stratified squamous

nonkeratinized epithelium



Lip, oral Mucosa



Teeth

Mineralized Components : Enamel

96% calcium hydroxyapatite

Dentin


Cementum


Pulp, a richly vascularized

and innervated loose

connective tissue



stratified squamous

nonkeratinized

epithelium

Orthokeratinized

Parakeratinized



Humans have two sets

of teeth

20 deciduous (milk)teeth

replaced by 32

permanent (adult) teeth

composed of 20succedaneous teeth and

12 molars (accessional

teeth).



The Tongue

The tongue is a mass of striated muscle coveredby a mucous membrane

Mucosal folds lingual papillae

Lamina propria

Muscles: Intrinsic muscles

Originate in the tongue

Alter the shape of the tongue

Extrinsic muscles

Outside the tongue

Moving tongue in & out, side to side



The Tongue



The Tongue Muscle



Papillae

Papillae are elevations of the oral epithelium andlamina propria

four types of lingual papillae:

filiform papillae

stratified squamous keratinized epithelium fungiform papilla

stratified squamous nonkeratinized

Fungiform papillae have taste buds

Foliate papillae circumvallate papillae



Filiform Papilae



Circumvalata papilae



Fungiform papilae



Foliata papilae



Taste Bud



Alimentary Canal

The esophagus, Stomach,

Small intestine (duodenum, jejunum, and ileum),

Large intestine (cecum, colon, rectum, anal canal,

and appendix).



Alimentary canal Histology

Layers: mucosa,

submucosa,

muscularis externa,

and serosa (or adventitia). similar throughout the length of the digestive tract

but display regional modifications and

specializations.



Alimentary canal Histology

Mucosa Epithelium

lamina propria

mucosa-associated lymphoid tissue (MALT) system

muscularis mucosae

Submucosa dense, irregular fibroelastic connective tissue layer

no glands except in the esophagus and duodenum

Muscularis Externa inner circular and outer longitudinal smooth muscle layers

Serosa and Adventitia Serosa surround by mesothelium



Esophagus Muscular tubes

Mucosa stratified squamous epithelium

lamina propria

muscularis mucosae

Submucosa esophageal glands

Muscularis Externa andAdventitia inner circular and outer longitudinal

the upper third of the esophagushas mostly skeletal muscle

the middle third has both skeletaland smooth muscle;

and the lowest third has only smoothmuscle fibers

The esophagus is covered by anadventitia until it pierces thediaphragm, after which it iscovered by a serosa



Esophagus-Gaster Junction



Gaster

Cardia: a narrow region atthe gastroesophageal

junction, 2 to 3 cm wide

Fundus: a dome-shapedregion to the left of theesophagus, frequently filledwith gas

Body (corpus): the largestportion, responsible for theformation of chyme

Pylorus (pyloric antrum): afunnel-shaped, constrictedportion equipped with a thick

pyloric sphincter thatcontrols the intermittentrelease of chyme into theduodenum



Gastric Histology

All the gastric regionsdisplay rugae

longitudinal folds of themucosa andsubmucosa, but transverse

in the antrum the epithelial lining of

the stomach invaginatesinto the mucosa,

forming gastric pits(foveolae), shallowest in the cardiac

region

and deepest in the

pyloric region



Gastric Histology

Mucosa Epithelia

simple columnar epithelium

Lamina Propria Connective tissue, fundic glands

Mucous Neck Cells Regenerative (Stem) Cells

Parietal (Oxyntic) Cells

Chief (Zymogenic) Cells

DNES Cells (APUD or Enteroendocrine Cells

Muscularis mucosa

Composed by three layers of muscle SubMucosa

Muscularis Externa

Serosa



Fundic Mucosa



Mucus Cells not Goblet cells



A: Gastric Pit

B: gastric Glands



Gastric Pit (Neck region)

Simple

columnar

epithelia

Neckmucous

cells

Parietal

cells



Gastric Pit (Base Region)

A : Parietal

Cells

B: Chief cells

M f



Mucosa of

the Cardiac Region VS Pyloric Regions

Cardiac Pyloric

the gastric pits are

shallower

the base of its glands ishighly coiled

composed mostly of

surface-lining cells

predominant cell type in

the pylorus is the

mucous neck cell the gastric pits of the

pyloric region are

deeper

Pyloric glands arehighly convoluted and

tend to branch

C di i



Cardiac region

Pyloric Region

CardiacR i



Region

PyloricRegion



Muscularis Mucosa & SubMucosa



Muscularis Externa

Inner oblique layer,

middle circular layer,

and



Small Intestine

duodenum,

jejunum, and ileum.

Layers:

Intestinal Mucosa

Sub Mucosa

Muscularis Externa

Serosa



Intestinal Mucosa Epithelium

The simple columnar epithelium, Goblet cells , DNES cells

Lamina Propria

the crypts of Lieberkühn, lymphoid nodules

Muscularis Mucosae

inner circular layer and an outer longitudinal

Submucosa

Muscularis Externa inner circular layer and an outer longitudinal

Serosa



Modifications of the Luminal Surface

Plicae circulares (valves of Kerckring)

transverse folds of the submucosa and mucosa

Villi

protrusions of the lamina propria

Microvilli modifications of the apical plasmalemma

crypts of Lieberkühn

Invaginations of the epithelium into the lamina propria

between the villi



Plicae circulares



Villi



Microvilli



crypts of Lieberkühn



Paneth Cells



Histology of Small Intestine

Organ Epithelium

LaminaPropria

Muscularis Mucosa

Submucosa

Muscularis Externa

Serosa/adventitia

Duodenum Simple

columnar

(goblet

cells)

Crypts of

Lieberküh

n

Inner

circular,

outer

longitudinal

Brunner's

glands

Inner

circular,

outer

longitudinal

Serosa

and

adventitia

Jejunum Simple

columnar

(goblet

cells)

Crypts of

Lieberküh

n

Inner

circular,

outer

longitudina

l

No glands Inner

circular,

outer

longitudina

l

Serosa

Ileum Simple

columnar

(goblet

cells)

Crypts of

Lieberküh

n; Peyer's

patches

Inner

circular,

outer

longitudina

l

No glands

(Peyer's

patches

may

extend into

this layer)

Inner

circular,

outer

longitudina

l

Serosa



Duodenum

Lumen Of DuodenumLumen Of Pyloric stomach

Pyloric Sphincter



Duodenum



Brunner's glands



Jejunum

the longestsegment of the

small intestine

highly coiled

submucosa and

mucosa fold, called

plicae circulares

(or valves ofKerckring)



Ileum



Vermiform appendix

Lumen stellate/star-shaped

Mucosa:

Tidak punya villi

Epitel kolumner simpleks

Lamina propria: CT + banyak lymphoid nodule

Crypte Lieberkuhn

Muscularis mucosa, submucosa, muscularis externa,

serosa ~ small intestine



Appendix vermiformis

Keterangan:

1. Lumen

2. Mukosa

3. Submukosa

4. Muskularis

eksterna

5. Serosa

6. Noduli limfatici

1

2

3

4

5

6



Large Intestine

cecum, colon,rectum, and anus

No vili, Crypts of

Lieberkuhn (+),

paneth cell (-) Bundle of

muscularis

externa

Taenia coli



The colon: 450X



Muscularis externa

-Inner circular layer:

Submucosa

Mucosa

Muscularismucosa

Serosa & muscularis externa of the colon: 450X



Inner circular layerOuter longitudinal layer

Serosa

Muscularis Externa

Muscularis Externa



Rectum & Anal Canal

Rectum ~ colon

Anal Canal

simple columnar

epithelium

unkeratinized

stratified

squamousepithelium

Epitel squamous

kompleks keratin

Anal canal



External anal sphincter

Internal anal sphincter

Anal canalRectum

Anal skin



Glands

major salivary glands

parotid, submandibular, and sublingual glands),

the pancreas,

the liver

gallbladder

l f l l d



Histology of Salivary Glands

Secretory Portions

Serous cells Mucous cells

Myoepithelial cells (basketcells)

Duct Portions

The smallest branches =

intercalated ducts = layer ofsmall cuboidal cells,myoepithelial cells

Several intercalated ductsmerge with each other to formstriated ducts = single layer ofcuboidal to low columnar cells

Striatedintralobular ductsinterlobar ducts. terminal (principal)duct



Glandula Sublingualis secretory portion

P id l d



Parotid glands

the largest of thesalivary glands

produces only

about 30%

saliva output• Ductus intercalaris

Ductus striatus

duktus excretorius

interlobularis

Serous secretion

S bli l Gl d



Sublingual Gland

composed most ly of mucous acin i wi th serous demi lunes,

and prod uces a m ixed s aliva.

D il



Demiluna serosa

S b dib l Gl d



Submandibular Glands

produc es 60% of the total sal ivary outpu t

Mixed glands



E i P



Exocrine Pancreas

acinar cell

secretory granules

(zymogen granules)



H



Hepar

the liver has bothendocrine and

exocrine functions

Composed by

hepatocyte



The Three Concepts of Li er Lob les



The Three Concepts of Liver Lobules

The classical liver lobule

blood flows from theperiphery to the center of

the lobule into the central

vein

portal lobule all hepatocytes that deliver

their bile to a particular

interlobular bile duct

constitute a lobule

hepatic acinus (acinusof Rappaport).

blood flow from the

distributing arteriole

Portal Triad



Portal Triad

Gallbladder



Gallbladder

Layer:

epithelium, lamina

propria, smooth muscle,

and serosa/adventitia



Questions ??



End of lecture

Histology of Digestive System

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