Colon is supplied by all except ?
**Core Concept**
The colon, also known as the large intestine, is a vital part of the gastrointestinal tract that plays a crucial role in water absorption, electrolyte balance, and waste elimination. The colon is supplied by a complex network of blood vessels, including arteries and veins, which provide oxygen and nutrients to its tissues.
**Why the Correct Answer is Right**
The correct answer is related to the vascular supply of the colon. The colon receives its blood supply from branches of the superior and inferior mesenteric arteries. The superior mesenteric artery supplies the ascending and transverse colon, while the inferior mesenteric artery supplies the descending colon and sigmoid colon. The rectum, however, receives its blood supply from the inferior mesenteric artery and the middle rectal arteries, which are branches of the internal iliac arteries.
**Why Each Wrong Option is Incorrect**
* **Option A:** The superior mesenteric artery does supply the ascending and transverse colon, making this option incorrect.
* **Option B:** The inferior mesenteric artery does supply the descending colon and sigmoid colon, making this option incorrect.
* **Option C:** The rectum receives its blood supply from the inferior mesenteric artery and the middle rectal arteries, making this option incorrect.
**Clinical Pearl / High-Yield Fact**
The "watershed area" of the colon, which is the region between the territories of the superior and inferior mesenteric arteries, is prone to ischemia and infarction due to its limited blood supply.
**Correct Answer: C. The rectum receives its blood supply from the inferior mesenteric artery and the middle rectal arteries.**