artery via the short gastric branches. The splenic artery also gives rise to the
left gastro-omental artery that runs along the greater curvature to anasto-
mose with the right gastro-omental branch that arises indirectly from the
common hepatic artery. Noneof the other arteries, common hepatic
(answer a),the inferior phrenic (answer b),and superior mesenteric
(answer e)are close to the pancreas.
407.The answer is e.(Moore and Dalley, pp 280, 306, 450–451.)Potential
causes of blood in the stool (hematochezia) include diverticular disease, inter-
nal hemorrhoids, and colorectal cancer [thus not (answers a and b)]. Diver-
ticular disease mainly affects middle age and older adults. It is an
outpocketing of the lining of the colon, occurring most frequently in the sig-
moid colon. Diverticular disease may be caused by lack of fiber in the diet. If
the diverticula get large, they may rupture blood vessels and bleed. Internal
hemorrhoids are dilated (varicose) veins that develop above the pectinate line
within the internal rectal venous plexus. They can develop as a consequence
of hepatic cirrhosis, which could cause portal hypertension as blood resis-
tance within the liver increases. Venous blood within the portal system back-
flows down the superior rectal veins and into the inferior rectal veins, that are
part of the systemic venous system that does nothave to pass through the liver.
Most colorectal cancers initially develop as polyps, which continue to grow
and differentiate and in later stages develop increased vascularity and bleed.
External hemorrhoids and fissures may result in blood in the stool, but are
generally painful [thus not (answers c and d)].
408.The answer is e.(Moore and Dalley, pp 306, 445, 450–451.)A, b, and c.
The rectum receives blood from three different arteries, which come from three
different major branches: superior rectal artery off the inferior mesenteric
artery; middle rectal artery off the internal iliac artery, and inferior rectal artery
off the internal pudendal artery (Moore & Dalley, p 445). Thus noneof the
other answers are complete (answers a, b, c, and d).There are also three sets
of veins: superior rectal veins, which drain into the hepatic portal system;
middle rectal veins, which drain into the internal iliac veins (part of the sys-
temic venous system); and inferior rectal veins, which drain into internal
pudendal veins (also part of the systemic venous system). Because the internal
rectal venous plexus is a potential site of portal-systemic anastomoses, inter-
nal hemorrhoids may be an indication of liver pathology.
Abdomen Answers 527