Download small intestine duodenum jejunum ileum

SMALL INTESTINE
DUODENUM
JEJUNUM
ILEUM
SMALL INTESTINE
• Serosa:Visceral peritoneum.
• Muscularis externa:Thick inner and thin outer layer.
• Sub mucosa:Brunner’s glands –
in duodenum
secretes fluid rich in bicarbonate.
• Mucosa:• Villi:
finger like projection.
Duodenum– broad and ridge like.
Jejunum –tall and leaf like.
Ileum
–short and finger like.
• Valves of kerkring
– large circular folds of mucosa.
• Crypts of lieberkuhn – intestinal glands.
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Epithelium:1. Absorptive columnar cells or enterocytes.
Each cell bears around 3,000 microvilli.
2. Goblet cell – mucous protects & lubricates
intestinal wall.
• Crypts of lieberkuhn (intestinal glands):• These are tubular pits opening in between the
bases of villi.
 Types of cells in crypts:• Columnar cells:• Mucous (Goblet) cells:-
• Paneth cells:Present in deeper part of intestinal glands.
Rich in zinc and secretes lysozymes which
is a antibacterial substance.
• Stem cells:
Undifferentiated mitotic cells.
• Enteroendocrine cells:
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Pyramidal or columnar in shape
with apical nuclei
Infranuclear black granules that stain with silver salts.
Also called argentaphil cells or enterochromaffin cells.
Intestinal glands
• Lamina propria:
• Crypts of leiberkuhn in duodenum.
• Contains Crypts of leiberkuhn and solitary
lymphoid follicles in jejunum.
• Peyers patches in ileum –10 to 250 lymphoid
follicles
DUODENUM
JEJUNUM
ILEUM
Features
Villi
Duodenum
Broad ridges
Goblet cells Few
Lamina
Crypts of
propria
lieberkuhn
Sub
mucosa
Brunner's
glands
Jejunum
Tall foliate
Few
Crypts of
lieberkuhn &
diffuse
lymphocytes
Only
connective
tissue
Ileum
Short finger
like
More
Crypts of
lieberkuhn &
Payers
patches.
Payers
patches