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Difficulty: HardHuman Anatomy and Body Systems

While most systemic veins carry blood directly back toward the heart into the venae cavae, portal systems in the human body route venous blood through a secondary specialized capillary network before entering general circulation. Which of the following correctly describes the pathway, oxygenation state, and primary physiological cargo of blood traveling through the hepatic portal vein?

  1. A
    It transports oxygenated, nutrient-rich blood from the small intestine directly into the inferior vena cava.
  2. B
    It transports oxygenated, hormone-rich blood from the abdominal aorta directly to the liver sinusoids.
  3. It transports deoxygenated, nutrient-rich blood from the digestive organs to the liver capillary beds.Answer
  4. D
    It transports deoxygenated, waste-depleted blood from the liver sinusoids directly into the right atrium.

Answer

The hepatic portal vein transports deoxygenated, nutrient-rich blood from the digestive organs to the liver capillary beds.
The correct answer accurately characterizes the hepatic portal circulation. Unlike typical veins that empty directly into the central venous return, the hepatic portal vein collects venous (deoxygenated) blood that has absorbed nutrients from the gastrointestinal capillaries and routes it straight into the liver capillary beds (sinusoids) for processing before it reaches the systemic circulation.

Step-by-Step Solution

1
Identify the anatomical definition and function of a portal system.
A portal system is a vascular arrangement where blood passes through two consecutive capillary beds connected by a portal vein before returning to the heart.
Understanding portal architecture distinguishes portal vessels from typical systemic veins and systemic arteries.
2
Determine the origin, destination, and oxygenation state of blood in the hepatic portal vein.
Blood leaves the first capillary bed in the stomach, intestines, pancreas, and spleen (where oxygen was delivered to tissues, leaving it deoxygenated) and travels into the hepatic portal vein toward the liver.
Venous drainage from visceral organs carries deoxygenated blood.
3
Determine the functional cargo and secondary capillary bed.
The blood carries absorbed monosaccharides, amino acids, electrolytes, and water directly into the liver sinusoids (second capillary bed) for metabolic regulation and toxin clearance prior to systemic distribution.
The liver processes incoming dietary nutrients before the blood is collected by hepatic veins and directed to the inferior vena cava.

Key Concept

Hepatic Portal System Circulation and Microvascular Anatomy
Estimated Time:1m 30s
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Topics

Human Anatomy and Body Systems

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