Large Intestine Flashcards
1
Q
Describe the large intestine.
A
- extends from the ileocecal junction to the anus
- about 1.5 m in length
2
Q
What is the function of the large intestine?
A
- to convert the liquid contents of the ileum into semisolid feces by absorbing water
- also involved in synthesis and absorption of some vitamins, which require bacterial activity (vitamin K - involved in blood clotting)
3
Q
What are the parts of the large intestine?
A
- cecum
- appendix
- colon
- rectum and anal canal
4
Q
What is the cecum?
A
- a blind pouch found below the ileocecal junction
- lies within the right iliac fossa
5
Q
What is the ileal fold?
A
- consists of two flaps which surround the ileal orifice (opening of the terminal ileum into the cecum)
- the flaps fuse laterally to form the frenula
- function: prevents backflow of feces into the small intestine
6
Q
What is the appendix?
A
- a narrow muscular tube which contains lymphoid tissue in its walls
- it arises from the posteromedial aspect of the cecum, and is attached to the mesentery of the ileum by the mesoappendix
- functions in immune defense of the alimentary canal
- its lumen opens into the cecum via an orifice located below the ileal orifice
- the position of the appendix is variable; it’s most common position is retrocecal; second most common is pelvic
7
Q
What is appendicitis?
A
- inflammation of the appendix
- most common intra-abdominal inflammatory condition
- symptoms usually begin as umbilical pain, which then localizes to the right lower quadrant
- position of the appendix is variable and can affect where pain is felt
- if untreated, the appendix may rupture, leading to peritonitis
- cause by obstruction of the lumen due to:
1. lymphoid hyperplasia - in kids and teenagers, also in lymphoma cases
2. fecal impaction - affects people who have a lot of issues with constipation
8
Q
What are the parts of the colon?
A
- Ascending colon: from the ileocecal junction to the right colic (hepatic) flexure; retroperitoneal
- Transverse colon: from the right colic flexure to the left colic (splenic) flexure; lies within the peritoneal cavity and is attached to the posterior body wall by the transverse mesocolon
- Descending colon: from the left colic flexure to the pelvic brim; retroperitoneal
- Sigmoid colon: from the pelvic brim to the front of hte sacrum, where it becomes the rectum; some people have a long sigmoid colon, and are more prone to developing bowel obstruction; lies within the peritoneal cavity and is attached to the posterior body wall by the sigmoid mesocolon
9
Q
What are the taeniae coli?
A
three narrow longitudinal bands of muscle seen most prominently in the cecum and ascending colon
10
Q
What are the haustra of colon?
A
sacculations or outpouchings of the colon
11
Q
What are omental appendices?
A
small masses of fat which are covered with visceral peritoneum, and which extend from the colon
12
Q
What are the rectum and anal canal?
A
the terminal portions of the large intestine
13
Q
What is diverticulosis?
A
- herniations of the mucosa of the colon through the muscular layer, without inflammation
- most common in individuals over 40 years of age
- if the diverticuli become inflamed, the condition is called diverticulosis
- if results in abdominal pain, diarrhea, and in some cases, abscess
- related to a low fiber diet
- may be treated with laser endoscopy
- radiographically, it is characterized by numerous outpouchings along the colon
14
Q
What is ulcerative colitis?
A
- severe inflammation and ulceration of the rectum and lower colon
- usually restricted to the mucosa
- abdominal pain and diarrhea are symptoms
- bowel perforation may occur
- radiographically, the bowel appears restricted (tear-drop deformity)
15
Q
What is irritable bowel syndrome?
A
- a common condition involving recurrent abdominal pain and diarrhea with no inflammation or deterioration in health
- symptoms are caused by abnormal muscular contractions of the colon
- the cause is unknown, but symptoms are often brought on by stress and anxiety
