Which of the following is false about portal vein?
**Core Concept**
The portal vein is a vital blood vessel that plays a crucial role in the hepatic portal system, responsible for draining blood from the gastrointestinal tract, spleen, and pancreas into the liver. The portal vein is formed by the confluence of the superior mesenteric vein and the splenic vein.
**Why the Correct Answer is Right**
The portal vein is a major blood vessel that carries nutrient-rich, deoxygenated blood from the gastrointestinal tract to the liver for detoxification, metabolism, and nutrient processing. The portal vein is composed of smooth muscle and elastic fibers, allowing it to expand and accommodate varying blood volumes. The hepatic portal system is essential for maintaining liver function and overall metabolic health.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the portal vein does not originate from the inferior vena cava. Instead, it is formed by the confluence of the superior mesenteric vein and the splenic vein.
**Option B:** This option is incorrect because the portal vein does not drain into the inferior vena cava. Instead, it drains into the hepatic sinusoids of the liver.
**Option C:** This option is incorrect because the portal vein is not a major artery. It is a major vein that plays a crucial role in the hepatic portal system.
**Clinical Pearl / High-Yield Fact**
The portal vein is susceptible to thrombosis, which can lead to portal hypertension and liver cirrhosis. This is often due to underlying conditions such as liver disease, malignancy, or portal vein stenosis.
**Correct Answer:** A.