Large Intestine Flashcards
How long is the large intestine?
1.5 meters
What is longer, the SI or LI?
SI
What is wider in diameter, the SI or LI?
LI
What extra function is the large intestine a part of?
Synthesis of some vitamins that require bacterial action
What is an example of a vitamin synthesized in the large intestine?
Vitamin K (important for blood clotting)
What are the four parts of the large intestine?
Cecum, appendix, colon, and rectum/anal canal
What is the cecum?
Blind pouch found below the ileocecal junction
Where does the cecum lie?
Within the right iliac fossa
What are the two flaps that surround the ileal orifice called?
Ileal fold
What is the function of the ileal fold?
To prevent back flow of feces into the small intestine
The lateral fusion of the ileal fold is called what?
Frenula
What is the newly discovered function of the appendix?
Immune defense and regulation of bacteria
What is the most common position of the appendix?
Retrocecal
What is the second most common position of the appendix?
Pelvic
What is a great word to describe the position of the appendix?
Variable
What is the appendix?
A narrow muscular tube which contains lymphoid tissue that arises from the posteromedial aspect of the cecum
What is appendicitis?
Inflammation of the vermiform appendix
What is the most common intra-abdominal inflammatory condition in the world?
Appendicitis
Where is pain usually felt with appendicitis?
Pain begins as umbilical pain then localizes to the right lower quadrant
What can happen if appendicitis is left untreated?
It may rupture, resulting in peritonitis
What causes appendicitis?
Obstruction of the lumen due to either lymphoid hyperplasia or fecal impaction
Obstruction of the lumen due to lymphoid hyperplasia resulting in appendicitis most commonly occurs among what population?
Children during the growth process
The ascending colon is on what side of the body?
Right
The descending colon is on what side of the body?
Left
What is the pathway of the ascending colon?
From the ileocecal junction to the right colic (hepatic) flexure
What is the pathway of the transverse colon?
From the right colic flexure to the left colic (splenic) flexure
What is the pathway of the descending colon?
From the left colic flexure to the pelvic brim
What is the pathway of the sigmoid colon?
From the pelvic brim to the front of the sacrum, where it becomes the rectum
Are the appendix and cecum intraperitoneal or retroperitoneal?
Intraperitoneal
What parts of the colon are retroperitoneal & therefore immobile?
Ascending and descending colon
What parts of the colon lie within the peritoneal cavity?
Transverse and sigmoid colon
What is the mesentery of the transverse and sigmoid colon called?
Transverse and sigmoid mesocolon
What are the three narrow longitudinal bands of muscle seen most prominently in the cecum and ascending colon?
Taeniae coli
Where do the taeniae coli end?
Meet together to end at the appendix
What are the sacculations or outpouchings of the colon called?
Haustra of the colon
What are the small masses of fat that are covered with visceral peritoneum that extend from the colon?
Omental appendices
What are the terminal portions of the large intestine?
Rectum and anal canal
What is diverticulosis?
Herniations of the mucosa of the colon through the muscular layer without inflammation
Diverticulosis is most common among what age group?
Over 40 years of age
Where does diverticulosis most commonly occur?
Sigmoid colon
What is diverticulosis called when inflammation is present?
Diverticulitis
What results with diverticulitis?
Abdominal pain, diarrhea, and sometimes abscess
Diverticulitis is related to what type of diet?
Low fiber
How can diverticulitis possibly be treated?
Laser endoscopy
How is diverticulitis radiographically characterized?
Numerous outpouchings along the colon
What is ulcerative colitis?
Sever inflammation and ulceration of the rectum and lower colon
Ulcerative colitis is usually restrictive to what layer?
Mucosa
What are symptoms of ulcerative colitis?
Abdominal pain and diarrhea
What is seen radiographically with ulcerative colitis?
Bowel appears constricted
What else can occur with ulcerative colitis?
Bowel perforation
What is irritable bowl syndrome?
A common condition involving recurrent abdominal pain and diarrhea with no inflammation or deterioration in health
What causes the symptoms of irritable bowel syndrome?
Abnormal muscular contractions of the colon
What is the cause of irritable bowel syndrome?
Unknown, but the symptoms are probably brought on by stress and anxiety
The superior mesenteric artery supplies what part of the colon?
Right 2/3 of the transverse colon
What branch of the superior mesenteric artery supplies the pancreas and distal part of the duodenum?
Inferior pancreaticoduodenal artery
What are the 12-15 arteries from the superior mesenteric artery that branch and anastomose within the mesentery to form a series of arcades to supply the jejunum and ileum?
Jejunal and ileal arteries
What branch of the superior mesenteric artery descends to the ileocecal junction to supply the ascending colon, cecum, and appendix?
Ileocolic artery
What artery supplies the ascending colon?
Right colic artery
What artery supplies the transverse colon?
Middle colic artery
The inferior mesenteric artery supplies what part of the colon?
From the left 1/3 of the transverse colon to the upper part of the anal canal
What is the term for a complete occlusion of an intestinal vessel?
Bowel infarction
What is the fatality rate if a bowel infarction is transmural (all the way through the gut)?
95%
What branch of the inferior mesenteric artery supplies the descending colon?
Left colic artery
What branch of the inferior mesenteric artery supplies the sigmoid colon?
Sigmoid arteries
What branch of the inferior mesenteric artery supplies the rectum and upper part of the anal canal?
Superior rectal artery
What is the terminal branch of the inferior mesenteric artery?
Superior rectal artery
What are the branches of the superior mesenteric artery?
Inferior pancreaticoduodenal artery, jejunal/ileal arteries, ileocolic artery, right colic artery, and middle colic artery
What are the branches of the inferior mesenteric artery?
Left colic artery, sigmoid arteries, and superior rectal artery
What is the anastomotic channel that runs from the cecum to the sigmoid colon where all the branches of the superior and inferior mesenteric arteries empty?
Marginal artery
What is the vasa recta of the large intestine?
Straight terminal branches from the marginal artery to the large intestine
What is the innervation of the cecum through the right 2/3 of the transverse colon?
Autonomic fibers from the superior mesenteric plexus
What is the innervation of the left 1/3 of the transverse colon to the upper part of the anal canal?
Autonomic fibers from inferior mesenteric plexus and hypogastric plexus
Diarrhea, constipation, and other colon problems may be related to subluxations of what areas?
Lower thoracic, upper lumbar, or sacral regions
Chronic constipation is associated with an increased risk of what conditions?
Hiatal hernia, inguinal hernia, diverticulosis, and colon cancer
