Which structure in the digestive system comes into direct contact with the circulatory system for the transfer of nutrients into the blood?
Answer (2)
The structure in the digestive system that directly contacts the circulatory system to transfer nutrients into the blood is the small intestine.
The small intestine is lined with villi, and each villus contains many microvilli that greatly increase the surface area for absorption. Within the villi, there are capillaries and lymphatic vessels that collect nutrients: the capillaries absorb amino acids and simple sugars directly into the bloodstream, while lipids are absorbed by the lymphatic vessels. The veins that collect nutrient-rich blood from the small intestine empty into the hepatic portal system, which transports the nutrients to the liver for processing before they enter the systemic circulation.
An anatomical arrangement ensures that xenobiotics absorbed from the intestine go to the liver first through the portal vein before entering the systemic circulation, a phenomenon known as the 'first pass.' This process underlines the interrelationship between the digestive and cardiovascular systems, highlighting how different systems within the body cooperate to maintain overall homeostasis.
The small intestine is the structure in the digestive system that comes into direct contact with the circulatory system for nutrient transfer. Villi and microvilli within the small intestine facilitate the absorption of nutrients into the blood, which then goes to the liver for processing. This process demonstrates how the digestive and circulatory systems work together to deliver essential nutrients to the body.
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