Histology of gastrointestinal tract Histology of gastrointestinal tract Histology of gastrointestinal tract Histology of gastrointestinal tract Gastrointestinal tract has four distinct layers Mucosa Mucosa Epithelium L i i i f i Lamina propria – supporting function Consist of loose connective tissue (elastic fibers), vessels, nerves, l d l h id i (i i ) glands, lymphoid aggregation (immunity) Muscularis mucosae – thin smooth muscle layer that is involved in the movement of mucosa
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Histology of gastrointestinal tractHistology of gastrointestinal tractHistology of gastrointestinal tractHistology of gastrointestinal tract
Gastrointestinal tract has four distinct layers Mucosa Mucosa
Epithelium
L i i i f i Lamina propria – supporting function Consist of loose connective tissue (elastic fibers), vessels, nerves,
l d l h id i (i i )glands, lymphoid aggregation (immunity)
Muscularis mucosae – thin smooth muscle layer that is involved in the movement of mucosa
Submucosa Consist of loose connective tissue, large vessels, nerves,Consist of loose connective tissue, large vessels, nerves,
glands, submucosal, submucosus nerve plexus (Meissner´s plexus), and lymphoid aggregation (immunity)gg g
Muscularis propria Muscular wall consist of smooth muscle arranged in two Muscular wall consist of smooth muscle arranged in two
layers, inner circular and outer longitudinal Participate in the peristaltic contraction Participate in the peristaltic contraction Myenteric nerve plexus (Auerbach´s plexus) is located
between these two layersbetween these two layersAdventitia (serosa)
C i f l i i l l Consist of loose connective tissue, large vessels, nerves, adipose tissue covered by the simple squamous epithelium (mesothelium)(mesothelium)
Microscopic preparation Microscopic preparation –– the mucosa of the the mucosa of the tonguetongue
Circumvallate papillae
Stratified squamous epithelium
Taste buds embedded in the epithelium Taste buds embedded in the epithelium
Lamina propria form the body of papilla
Microscopic preparation Microscopic preparation –– the mucosa of the the mucosa of the tonguetonguetonguetongue
Circumvallate papilla Filiform papilla
epithelium
Lamina propria mucosae
Taste buds
Microscopic preparation Microscopic preparation –– the mucosa of the the mucosa of the tonguetongue (taste buds)(taste buds)
Mucosa Simple columnar epithelium enters lamina propria and form the
gastric pits Gastric glands enters these gastric pits
Cell population of epitheliump p p Surface mucous cells – production of protective bicarbonate ions
(against hydrochloric acid)( g y ) Parietal (oxyntic) cells – production hydrochloric acid Zymogenic (peptic) cells – located towards the base of the glandsy g (p p ) g
Consist of hepatocytes, separated by the vascular channels called i id (bl d f h h i d l i )sinusoids (blood from the hepatic artery and portal vein)
The blood from sinusoids flows into the centrilobular venule → The blood from sinusoids flows into the centrilobular venule → hepatic vein → inferior vena cava
Bile is secreted by hepatocytes → enters bile canaliculi thatempty into small bile ducts
Portal tract (portal triad) located at the angles of the hexagon Portal tract is consist of the vein (branch of hepatic portal vein – nutrition),
the artery (br n h hep ti rter o gen) nd the bile ductthe artery (branch hepatic artery – oxygen) and the bile duct