The document summarizes the structure and features of the large intestine, liver, gallbladder, and pancreas. The large intestine consists of the cecum, colon, and rectum, and has simple columnar epithelium and goblet cells. The liver is divided into lobules by connective tissue sheets and contains hepatocytes and sinusoids. The gallbladder has a muscular wall with three tunics. The pancreas has both exocrine and endocrine functions, with exocrine pancreas made up of acini that produce enzymes and endocrine islets of Langerhans.

1. Digestive System-3
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2. Large Intestine
• Comprises of
– Caecum
– Colon
– Rectum
• Common Characteristics
– no plicae circulares
– Absence of Villi
– Longer less coiled, simple tubular glands with
many goblet cells.

3. Large Intestine (Colon)
• Mucosa:
– Epithelium: Simple columnar Epithelium with goblet cells,
– Lamina Propria with Intestinal Glands
– Muscularis mucosae
• Sub-Mucosa:
– Connective tissue, cells and fibers with blood vessels and nerves.
• Muscularis Externa
– Inner circular layer of smooth muscles
– Outer Longitudinal muscles, condensed to from three longitudinal
bands (Taeniae coli).
• Serosa

7. Rectum
• Same as of colon except that muscularis
externa doesn't have taenie coli bands.
Muscularis externa inner circular layer and
outer longitudinal muscles.

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10. Accessory organs of the digestive
system
• Located outside of the digestive tube.
• deliver their secretory products to the oral
cavity or small intestine by excretory ducts.
– Salivary glands (Covered)
– liver,
– gallbladder,
– Pancreas.

11. Liver
• The liver is covered by a thin connective tissue
capsule (Glisson's capsule) that becomes thicker at
the hilum.
• The Liver Lobule
– Sheets of connective tissue divide the liver into thousands
of small units called lobules. A lobule is roughly hexagonal
in shape, with portal triads at the vertices and a central
vein in the middle.
– from Central vein radiate plates of liver cells, called
hepatocytes, and sinusoids having Kupffer cells(capillaries)
toward the periphery.
– Connective tissue make the boundary of each lobule
(extensions of capsules inside liver).
– In connective tissue forms portal areas, where branches of
the hepatic artery, hepatic portal vein and bile duct.

12. Liver

16. Gallbladder
• A muscular sac, its wall composed of three tunics.
• Mucosa
– Epithelium: Simple columnar Epithelium
– Lamina propria
• Muscularis Externa
– muscularis externa (muscle layer) contains bundles of
smooth muscle cells, collagen and elastic fibres.
• Adventitia/ Serosa

19. Pancreas
• The pancreas is the main enzyme producing accessory
gland of the digestive system. It has both exocrine and
endocrine functions.
• Exocrine Pancreas
– Its forms majority of pancreas, consist of serous acini having
zymogen cells.
– Acini opens into intercalated ducts (ducts lined by simple
Cuboidal epithelium).
– Intercalated ducts opens into interlobular duct (located in
inter lobular connective tissue).
• Endocrine Pancreas
– Between serous acini are located small lightly stained Islets
(Islets of Langerhans), the endocrine part of Pancreas.
– Islets composed of Alpha, Beta and Delta cells).