Large Intestine Structure and Characteristics

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Questions and Answers

What is a predisposing factor for the development of carcinoma of the stomach?

Chronic gastric inflammation (correct)

Acute pancreatitis

Diverticulitis

Gallstones

What is the usual outcome for patients with carcinoma of the stomach if diagnosed late?

Poor prognosis with a short survival time (correct)

Cure with surgical resection

High chance of survival

Easy management with medications

What is the main function of the large intestine?

Fat emulsification

Protein digestion

Carbohydrate absorption

Fluid and salt absorption (correct)

Which part of the large intestine is located in the right groin?

Cecum Signup and view all the answers

What is the name of the bend in the large intestine just below the liver?

Hepatic flexure Signup and view all the answers

What is the name of the procedure used to check the liver for metastatic spread of stomach cancer?

Ultrasound scanning Signup and view all the answers

What is the usual presentation of carcinoma of the stomach?

Vague epigastric pain Signup and view all the answers

What is the 5-year survival rate for patients with carcinoma of the stomach if diagnosed early?

5-20% Signup and view all the answers

Where does the large intestine terminate?

The anal canal Signup and view all the answers

What is a characteristic of the large intestine in comparison to the small intestine?

It has a larger internal diameter Signup and view all the answers

What are the peritoneal-covered accumulations of fat associated with the colon?

The omental appendices Signup and view all the answers

What is the first part of the large intestine?

The cecum Signup and view all the answers

Where is the cecum located?

In the right iliac fossa Signup and view all the answers

What is attached to the posteromedial wall of the cecum?

The appendix Signup and view all the answers

Which artery supplies the rectum and anal canal?

Superior rectal artery Signup and view all the answers

What is characteristic of the taeniae coli?

They are narrow bands Signup and view all the answers

What is suspended from the terminal ileum by the mesoappendix?

The appendix Signup and view all the answers

What is the origin of the middle rectal artery?

Internal iliac artery Signup and view all the answers

What is the result of incomplete rotation and fixation of the midgut?

Malrotation Signup and view all the answers

What determines the position of the duodenojejunal junction?

Suspensory muscle of duodenum Signup and view all the answers

What is the term for twisting of the bowel?

Volvulus Signup and view all the answers

What is the consequence of twisting of the small bowel around the axis of the superior mesenteric artery?

Reduced blood flow Signup and view all the answers

At which level does the mesentery of the small bowel end?

Ileocecal junction Signup and view all the answers

What is the consequence of malrotation?

Increased risk of volvulus Signup and view all the answers

What are the possible symptoms of appendicitis?

Fever, nausea, and vomiting Signup and view all the answers

What is the treatment for appendicitis?

Appendectomy Signup and view all the answers

Which segment of the colon is located superiorly from the cecum?

Ascending colon Signup and view all the answers

What is the location of the right colic flexure?

Inferior to the right lobe of the liver Signup and view all the answers

What is the purpose of the phrenicocolic ligament?

Attaches the left colic flexure to the diaphragm Signup and view all the answers

What are the paracolic gutters?

Depressions formed between the lateral margins of the ascending and descending colon and the posterolateral abdominal wall Signup and view all the answers

What is the level of the vertebra where the sigmoid colon ends?

SIII Signup and view all the answers

What is the primary cause of mechanical bowel obstruction?

Intraluminal, mural, or extrinsic mass Signup and view all the answers

What is the characteristic of the sigmoid colon?

Quite mobile except at its beginning and end Signup and view all the answers

What is the most common cause of functional bowel obstruction?

Excessive intraoperative bowel handling Signup and view all the answers

What is the primary symptom of bowel obstruction?

Central abdominal, intermittent, colicky pain Signup and view all the answers

In which part of the colon is the intraluminal pressure potentially the highest?

Sigmoid colon Signup and view all the answers

What is a risk factor for the development of diverticular disease?

Poor dietary fiber intake Signup and view all the answers

What is the typical location of colonic diverticula in diverticular disease?

Predominantly in the sigmoid colon Signup and view all the answers

What is the effect of a high obstruction in the proximal small bowel on abdominal distention?

It will never produce abdominal distention Signup and view all the answers

What is the outcome for patients with multiple diverticula but no symptoms or signs?

They do not require any treatment Signup and view all the answers

Study Notes

Carcinoma of the Stomach

A common gastrointestinal malignancy
Chronic gastric inflammation, pernicious anemia, and polyps predispose to its development
Symptoms: vague epigastric pain, early fullness with eating, bleeding leading to chronic anemia, and obstruction
Diagnosis: barium and conventional radiology, endoscopy with biopsy, ultrasound scanning for liver metastasis, and computed tomography for surgical resectability
If diagnosed early, curative surgical resection is possible
Overall 5-year survival rate: 5-20%, with a mean survival time of 5-8 months

Large Intestine

Extends from the distal end of the ileum to the anus, approximately 1.5 m in adults
Absorbs fluids and salts from the gut contents, forming feces
Consists of:
- Cecum
- Appendix
- Colon
- Rectum
- Anal canal
Characteristics:
- Large internal diameter compared to the small intestine
- Peritoneal-covered accumulations of fat (the omental appendices)
- Segregation of longitudinal muscle in its walls into three narrow bands (the taeniae coli)
- Sacculations of the colon (the haustra of the colon)

Cecum

The first part of the large intestine
Inferior to the ileocecal opening and in the right iliac fossa
Intraperitoneal structure due to its mobility
Continuous with the ascending colon at the entrance of the ileum
May cross the pelvic brim to lie in the true pelvis

Appendix

A narrow, hollow, blind-ended tube connected to the cecum
Large aggregations of lymphoid tissue in its walls
Suspended from the terminal ileum by the mesoappendix
Point of attachment to the cecum is consistent with the highly visible free taeniae leading directly to the base of the appendix
Symptoms: fever, nausea, and vomiting
Treatment: appendectomy

Colon

Extends superiorly from the cecum
Consists of the ascending, transverse, descending, and sigmoid colon
Ascending and descending segments are (secondarily) retroperitoneal
Transverse and sigmoid segments are intraperitoneal
Right colic flexure: at the junction of the ascending and transverse colon
Left colic flexure: at the junction of the transverse and descending colon

Rectum and Anal Canal

The final segment of the colon begins above the pelvic inlet and extends to the level of vertebra SIII
S-shaped structure, mobile except at its beginning and end
Arterial supply:
- Superior rectal artery from the inferior mesenteric artery
- Middle rectal artery from the internal iliac artery
- Inferior rectal artery from the internal pudendal artery (from the internal iliac artery)

Clinical Correlation

Congenital Disorders of the Gastrointestinal Tract

Developmental anomalies can occur during gut development, many of which appear in the neonate or infant, and some of which are surgical emergencies
Occasionally, such disorders are diagnosed only in adults

Malrotation and Midgut Volvulus

Malrotation: incomplete rotation and fixation of the midgut after it has passed from the umbilical sac and returned to the abdominal coelom
Proximal attachment of the small bowel mesentery begins at the suspensory muscle of duodenum (ligament of Treitz)
Mesentery of the small bowel ends at the level of the ileocecal junction in the right lower quadrant
Twisting of the small bowel around the axis of the superior mesenteric artery can lead to a reduction of blood flow and infarction

Bowel Obstruction

A bowel obstruction can be either functional or due to a true obstruction
Mechanical obstruction: caused by an intraluminal, mural, or extrinsic mass
Functional obstruction: usually due to an inability of the bowel to peristalse, often due to a postsurgical state or abnormal electrolytes
Signs and symptoms depend on the level of the obstruction and include central abdominal, intermittent, colicky pain, abdominal distention, vomiting, and absolute constipation

Diverticular Disease

Development of multiple colonic diverticula, predominantly throughout the sigmoid colon
Poor dietary fiber intake and obesity are linked to diverticular disease
Presence of multiple diverticula does not necessarily require treatment
Many patients have no other symptoms or signs

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Description

This quiz covers the structure and characteristics of the large intestine, including its diameter, fat accumulations, and muscle segregation.