HTHSCI 1H06 B Lecture 16: GI Physiology: Intestines Notes
22 Jun 2018
School
Department
Course
Professor
INTESTINES
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Overview of Digestive Process
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In small intestine ,circular layer can constrict +segmentation mixes up food with
secretions
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chemical digestion →adding amylase to break down starches (carbs )
•Small Innit he accepts enzymes from accessory organs attached (pancreas +liver )
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Nutrients enter blood stream nsmall though ,if not Hats )they enter the lymphatic
then go into circulation
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Propulsion occurs throughout
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Anything left afterwards exits as feces 1Hzot electrolytes are extracted )
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Defecation involves aSC reflex mediated by the splanchnic nerves IParasympathetic
dl Vision of autonomic )
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voluntary
Divisions of the small Intestine
•small intestine Ibowel )
-Duodenum
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jejunum
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Mum
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large Intestine 1colon )
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4regions
>Caelum ,lol oh ,Rectum ,Anal Canal
Blood supply to the Intestines
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superior mesenteric
'
.supplies entire length of small in Haine tfirst third of large lhtelhne
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Distal large intestine Ihalfway of Hanshin colon →end )is supplied by Interior mesenteric
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they form many ands to Moses
Venous Drainage of the intestines
Hepahc Portal vein
Superior Mesenteric Vein Splemc Vein
Small In Hshne
Proximal 213 of large Inferior Mesenteric Vein
intestine
Distal '
13 of large intestine
•Pancreatic duodenal Vein :drains pancreas tduodenum into hepatic ten
The small Intestines
•Alterations In the small Intestines
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Plicae circulars :folding of mucosal layer
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villi :finger like projections that come off of plicae circular is
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micwvilli lbrush burden :each epithelial cell in mucosal layer which aids in digestion +
absorption
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Blood vessels ,lymphoma and nerves travel to and torn the majority of the small intestines by the
mellntlhy
Villi of the small Intestine
•Increase surface area for absorption and digestion In small lnkthhe
•
Lacteal :lymphatic go to tip ,where dietary fat Would go
Histology of Villi eatu HJ of the Duodenum
allows secretions IWM pancreas
Hepato pancreatic Ampulla →t liver into duodenum (4bicalb
-mucous )
jejunum ilium
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Duodenum
Wider became there Is food Smaller because residual matter
dissolves enzymes that Is still breaking down 11 he d"Hd
•
Name means 12 '(about 25cm )
when food occupies
•Most dente plicae circularly →mix food that Is being
lumen → stomach /pancreas + liver
passed from stomach to duodenum with secretions
from pancreas and liver for protection
•from acldk
Major site of absorption for Ca2t tFe /chyme
•Brunner 's Gland Hirst 10cm ):secrete bicavb rich mucus
