Module 2 Lecture 2 Part 1 Flashcards
What makes up the small intestine?
The small intestine is made up of the duodeum (25cm), the jejunum (2m) and the illeum (3m)
Why is the small intestine important?
The small intestine is important for digestive and absorptive functions (carbs, proteins and fats), also there are secretions and buffers provided by the pancreas and the gall bladder (live)
Where does digestion begin?
begins at the pyloric sphincter (stomach/small intestine transition) and ends at the Illeocecal valve (small intestine/large transition)
Label the parts of the small intestine
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What is the duodenum and what is its function?
the duodenum is a c-shaped tube, it is a mixing bowl - for chyme with bile and pancreatic secretions, it originates from the pyloric sphincter. The retroperitoneal apart from the most proximal part which is intraperitoneal
Label the pancreas
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Where does bile and pancreatic juice enter?
Bile and pancreatic juice enters the duodenum via the major duodenal papilla
What is the jejunum?
• Important digestive and absorptive functions (carbohydrates, proteins, and fat) • Begins at the duodeno-jejunal flexure (junction) and has no clear anatomical boundary with ileum • Intraperitoneal suspended by the mesentery proper
What is the illeum?
• Absorption of vitamin B12; salts and all products of digestion that were not absorbed by the jejunum • Intraperitoneal suspended by the mesentery proper
Where does the illeum end?
The illeum ends at a sphincter, the ileocecal valve, which controls the flow of materials from the ileum into the cecum of the large intestine
What are circular folds (plicae circulares)? and what do they do?
Plicae circulares increase surface area for absorption and to slow the passage of food, all parts of the small intestine contains plicae (circulares): circular folds of the intestinal lining
What are plicae?
Plicae are duplications of the mucous membrane, the transverse folds of the intestinal lining; increase intestinal surface area 3-fold
Where do plicae appear?
The appear in the duodenum and the jejunum prominently and becomes less common in aboral illeum
What are villi?
Villi are finger-like projections of the mucosa; increase intestinal surface area by 30- fold
What are micro-villi?
fingerlike structures on intestine cells; increase intestinal surface area 600-fold
Label all plicae and villi
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Where is the large intestine located?
Lies around the edges of the abdominal cavity and is
supported by the mesocolon
What is the large intestine consisted of?
The large intestine is consisted of 4 colons (ascending, transverse, descending and sigmoid)
What is the function of the large intestine?
The large intestine absorbs water and electrolytes from the remaining digested material to solidify into feces, there is no villi present and it stores fecal matter until defecation.
Label the large intestine
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