Human Anatomy Small and Large Intestine Quiz

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Questions and Answers

What suspends the transverse colon from the pancreas?

Sigmoid mesocolon

Rectal mesentery

Phrenicocolic ligament

Transverse mesocolon (correct)

Which describes the anatomical location of the descending colon?

Anterior to the diaphragm

Posterior to the stomach

Right lateral region

Left lateral region (correct)

What shape does the sigmoid colon most closely resemble?

S-shaped loop (correct)

Straight line

Triangle

Circle

How long is the average sigmoid colon?

10 to 15 inches Signup and view all the answers

What connects the left colic flexure to the diaphragm?

Phrenicocolic ligament Signup and view all the answers

Which statement about the rectum is true?

It extends from the sigmoid colon to the anal canal. Signup and view all the answers

What is the maximum length of the descending colon?

30 cm Signup and view all the answers

What distinguishes the small intestine from the large intestine?

It is mobile and has a mesentery. Signup and view all the answers

Where does the superior mesenteric artery arise?

Just below the coeliac trunk Signup and view all the answers

What does the middle colic artery primarily supply?

The right two-thirds of the transverse colon Signup and view all the answers

Which artery is a continuation of the inferior mesenteric artery?

Superior rectal artery Signup and view all the answers

What is the primary function of the ileocolic artery?

Supplying the appendix and lower ascending colon Signup and view all the answers

Which arteries anastomose with the inferior mesenteric artery?

Middle and inferior rectal arteries Signup and view all the answers

What is the role of the jejunal and ileal arteries?

They form an arterial arcade in the small bowel mesentery Signup and view all the answers

Which structure does the inferior mesenteric artery cross as it runs down and to the left?

Left common iliac artery Signup and view all the answers

What supplies the sigmoid and lower descending colon?

Sigmoid arteries Signup and view all the answers

What condition can result from bacteria entering the peritoneal cavity through intestinal perforation?

Acute peritonitis Signup and view all the answers

Which of the following is a potential source of bacteria that can lead to peritonitis?

Appendicitis rupture Signup and view all the answers

What is the consequence of a perforation in the intestinal wall?

Acute life-threatening peritonitis Signup and view all the answers

Which anatomical region is primarily affected when bacteria invade the peritoneal cavity?

Abdominal cavity Signup and view all the answers

Which of the following statements describes a result of bacterial interaction with the peritoneum?

Acute and life-threatening peritonitis Signup and view all the answers

What is a distinguishing feature of the large intestine compared to the small intestine?

Presence of teniae coli Signup and view all the answers

Which feature is found in the small intestine but absent in the large intestine?

Villi Signup and view all the answers

Which part of the GI tract receives blood supply from the coeliac trunk?

Foregut Signup and view all the answers

What structure is responsible for the sacculated appearance of the large intestine?

Haustra Signup and view all the answers

Which lymphoid tissue is found in the small intestine?

Peyer patches Signup and view all the answers

How is the blood supply to the inferior mesenteric artery classified in relation to the GI tract?

Hindgut Signup and view all the answers

What type of muscle arrangement characterizes the small intestine?

Continuous layer Signup and view all the answers

Which of the following is NOT a characteristic of the small intestine?

Absence of villi Signup and view all the answers

What primarily distinguishes the jejunum from the ileum?

The jejunum occupies the upper left part of the abdomen. Signup and view all the answers

Which of the following statements about the jejunum is true?

It is wider, thicker walled, and redder than the ileum. Signup and view all the answers

What anatomical feature marks the end of the ileum?

Ileocecal junction Signup and view all the answers

What is the characteristic appearance of the jejunum's mucous membrane due to?

Presence of permanent circular folds (plicae circulares) Signup and view all the answers

Where is the jejunal mesentery attached in relation to the aorta?

Above and to the left Signup and view all the answers

How many arcades do the jejunal mesenteric vessels typically form?

One or two Signup and view all the answers

Which of the following features is associated with the ileum?

Presence of Peyer patches Signup and view all the answers

What characteristic do ileal mesenteric vessels possess compared to jejunal vessels?

Numerous short terminal vasa recta Signup and view all the answers

Study Notes

Small Intestine

Comprises the jejunum and ileum, measuring 4-7 meters in length
Lies in the central abdomen, below the transverse colon
Jejunum: occupies the upper left part of the abdominal cavity, makes up the upper two fifths of the small intestine, begins at the duodenojejunal junction.
Ileum: occupies the lower right part of the abdominal cavity and the pelvic cavity, ends at the ileocecal junction.
Jejunum: wider and thicker-walled, redder than the ileum, has permanent circular folds (plicae circulares), has less fat in its mesentery, and its mesenteric vessels form only one or two arcades, with long and infrequent branches (vasa recta) passing to the intestinal wall.
Ileum: has numerous short terminal vasa recta that arise from a series of three or four or even more arcades, has aggregations of lymphoid tissue (Peyer patches) in the mucous membrane along the antimesenteric border.

Large Intestine

Divided into the cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum.
Cecum: hangs downward, suspended by the transverse mesocolon from the pancreas, the left colic flexure is higher than the right colic flexure and is suspended from the diaphragm by the phrenicocolic ligament.
Transverse colon: suspended from the anterior border of the pancreas by the transverse mesocolon.
Descending colon: the narrowest part of the colon, about 30 cm long, lies in the left lateral region.
Sigmoid colon: 10 to 15 inches (25 to 38 cm) long, mobile and hangs down into the pelvic cavity, lies in the left iliac region, extends from the pelvic brim to the front of the 3rd sacral vertebra, becomes the rectum.
Rectum: 13 cm long, extends from the sigmoid colon to the anal canal, lower part dilated to form the rectal ampulla, begins in front of the 3rd sacral segment, curving forwards with a loop to the left to the tip of the coccyx.

Blood Supply of the Small and Large Intestine

The GI tract is divided based on vascular supply into 3 parts (embryology):
- Coeliac trunk – foregut - from the lower 1/3 of the esophagus down to the middle of the second part of the duodenum
- Superior mesenteric - midgut - from the middle of the second part of the duodenum to the distal one third of the transverse colon.
- Inferior mesenteric - hindgut - the large intestine from the distal one third of the transverse colon to halfway down the anal canal.

Superior Mesenteric Artery

Arises just below the coeliac trunk (L1)
Runs down behind the neck of the pancreas
Passes anterior to the third part of the duodenum
Runs between layers of ‘The Mesentery’
Ends by anastomosing with the ileal branch of its own ileocolic branch.
Branches:
- Inferior pancreaticoduodenal artery - anastomose with the superior pancreaticoduodenal artery
- Middle colic artery - supplies the right two-thirds of the transverse colon
- Right colic artery - supplies the ascending colon, anastomoses with the ileocolic and middle colic arteries.
- Jejunal and ileal arteries - side-to-side anastomoses between these branches, and tiers of arterial arcades are formed.
- Ileocolic artery - supplies the caecum, appendix, and lower ascending colon.
  - Anterior and posterior cecal arteries
  - The appendicular artery is a branch of the posterior cecal artery.

Inferior Mesenteric Artery

Arises about 1.5 inches above the bifurcation of the aorta
Runs down and to the left, crossing the left common iliac artery
Becomes the Superior Rectal Artery, which anastomoses with the middle and inferior rectal arteries.
Branches:
- Left colic artery - supplies the transverse and descending colon, anastomoses with the middle colic and sigmoid arteries.
- Sigmoid arteries - supply the sigmoid and lower descending colon.
- Superior rectal artery - supplies the rectum and upper anal canal.

The Rectum

Supplied by the superior, middle, and inferior rectal arteries.
- Superior rectal artery: a direct continuation of the inferior mesenteric artery
- Middle rectal artery: a small branch of the internal iliac artery
- Inferior rectal artery: a branch of the internal pudendal artery in the perineum, it anastomoses with the middle rectal artery at the anorectal junction.

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Description

Test your knowledge on the anatomy of the small and large intestines, including the jejunum, ileum, and various sections of the large intestine. This quiz covers key features and differences between these digestive organs, their locations, and their anatomical significance in the human body.