Question

Difficulty: HardCirculatory and Transport Systems in Animals

During nutrient transport and circulatory routing in mammals, blood absorbed from the small intestine must travel through specific vascular networks and heart chambers before reaching systemic organs. What is the correct physiological sequence of blood flow from the intestinal capillaries to the main systemic artery?

  1. 1Blood absorbing nutrients at the intestinal villi drains into the hepatic portal vein and enters the liver sinusoids.
  2. 2Blood exits the liver via the hepatic vein and enters the inferior vena cava to reach the right atrium.
  3. 3Deoxygenated blood passes into the right ventricle and is pumped through the pulmonary trunk to the lungs.
  4. 4Oxygenated blood returns through pulmonary veins into the left atrium and flows into the left ventricle.
  5. 5Oxygenated blood is forcefully ejected from the thick-walled left ventricle into the systemic aorta.

Answer

The correct sequence of blood flow from the small intestine to systemic arterial delivery is: (1) Intestinal villi capillaries to hepatic portal vein and liver sinusoids -> (2) Hepatic vein to inferior vena cava and right atrium -> (3) Right ventricle through pulmonary trunk to pulmonary capillaries -> (4) Pulmonary veins to left atrium and left ventricle -> (5) Ejection from left ventricle into the systemic aorta.
The sequence correctly traces blood through the mammalian cardiovascular system: intestinal capillaries feed into the hepatic portal system (liver sinusoids), exiting via hepatic veins into the inferior vena cava to enter the right atrium. Deoxygenated blood is then pumped by the right ventricle to the lungs via pulmonary arteries. Oxygenated blood returns through pulmonary veins into the left atrium, moves to the left ventricle, and is ejected into the aorta for systemic distribution.

Step-by-Step Solution

1
Trace hepatic portal movement
Blood carrying absorbed nutrients drains from intestinal capillaries into the hepatic portal vein to be processed in liver sinusoids.
Mammalian circulatory design directs blood from digestive capillaries directly to liver capillaries before systemic venous return.
2
Trace venous return to the heart
Blood leaves the liver via the hepatic vein, joins the inferior vena cava, and enters the right atrium.
Systemic venous return collects deoxygenated blood and returns it to the right atrium.
3
Trace pulmonary arterial delivery
Blood flows into the right ventricle and is pumped into the pulmonary trunk/arteries leading to alveolar capillaries.
The right ventricle supplies the low-pressure pulmonary circuit for oxygenation.
4
Trace pulmonary venous return to systemic heart
Oxygenated blood returns via pulmonary veins into the left atrium and moves into the left ventricle.
Double circulation routes pulmonary return exclusively to the left side of the heart.
5
Trace systemic arterial ejection
The left ventricle contracts, forcing blood into the systemic aorta.
High hydrostatic pressure generated by the muscular left ventricle distributes oxygenated blood across the systemic body tissues.

Key Concept

Integration of Hepatic Portal and Pulmonary-Systemic Circuits
Estimated Time:2m 0s
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