BIOC34H3 Lecture Notes - Lecture 23: Pylorus, Diverticulosis, Diverticulitis
BIOC34:(Lecture(22( ( ( Final(
Mar.%21,%2018%
92%
Intestines,(Pancreas(and(Liver!
Small%Intestine%
• The%pyloric(valve%controls%entry%of%stomach%contents%into%the%small%
intestines%
• It%consists%of%3%main%sections%
o Duodenum%is%where%chyme%from%the%stomach%enters%along%with%
digestive%enzymes%from%pancreas,%bile%from%the%liver%&%gallbladder%
o Jejunum%is%after%
o Ileum%is%the%final%section%and%connects%to%
illeocecal(valve%of%the%large%intestines%
• Site%of%nutrient%absorption%
• Villi%line%the%inner%wall%and%have%microvilli%within%
to%enhance%surface%area%for%absorption%
• Cryptys(of(Lieberkuhn%are%the%pits%between%villi%à%
enhance%surface%area%available%for%absorption%
o Contain%cells%that%make%HCO3%to%decrease%acidity%of%the%chyme%
entering%form%the%acidic%stomach%
• Most%intestinal%enzymes%from%pancreas%can’t%function%in%acidic%environment%
so%the%HCO3%secretion%is%crucial%
Large%Intestine%
• The%cecum%is%the%first%region%of%the%large%intestines%and%connects%to%the%
colon%
• The%appendix%is%also%attached%there%
• The%colon%is%further%divided%into%the%
ascending(colon,%transverse(colon,%
descending(colon%and%sigmoid(colon%
• It%then%leads%to%the%rectum%which%
empties%via%the%anus%
Disorders%of%Large%Intestines%
• Appendicitis%occurs%when%the%appendix%
is%blocked%by%digested%food%causing%
inflammation%and%infection%
o If%it%ruptures%the%bacterial%
infection%is%usually%fatal%
• Fecalith%is%compact%feces%due%to%lack%of%fibre%à%causing%chronic%constipation%
• Diverticulosis%and%diverticulitis%are%both%disorders%of%the%sigmoid%colon%
o Diverticulosis%involves%weakened%muscles%surrounding%the%colon%
o Diverticulitis%occurs%when%pouches%formed%by%diverticulosis%become%
infected/inflamed%à%cause%pain%
o Also%caused%by%low%fibre%diet%
Document Summary
Small intestine: the pyloric valve controls entry of stomach contents into the small intestines. It then leads to the rectum which empties via the anus. Final: confirm diseases by inserting camera into the rectum and through the colon in colonoscopy. Insulin is secreted by cells that lower bgl by signaling cells to take up glucose from the blood. It also stimulates conversion of glucose into glycogen (how it is stored: glucagon raises bgl by signaling the breakdown of glycogen so free glucose can enter the blood. Insulin binds to insulin reveptor on plasma membranes that: Final: triggers activation of glut4 transporters, glut4 translocated to plasma membrane so that glucose can be taken into the cells. In diabetes milletus, some part of the insulin pathway isn"t functioning. In type 1 diabetes, there is an autoimmune disorder where insulin isn"t being released.