1. What type of blood vessel shown in the diagram is : A) an artery. B) A capillary. C) A vein. D) None of the above 2. At which location would blood with a low oxygen content and a high carbon dioxide content be found?

3. The diagram is based on structures found in which respiratory organ?

1. The blood vessel shown is a capillary.

2. The location where low oxygen blood and high carbon dioxide blood would be found is marked with the letter A in the diagram.

3. The diagram is based on structures found in the lungs, specifically the scheme of a pulmonary alveolus.

Explanation:

The scheme shows a pulmonary alveolus in contact with the corresponding pulmonary capillary, in addition to the alveolar blood flow. Between both structures is the capillary-alveolus barrier, through which gas exchange occurs.

According to what can be observed in the diagram, the vascular structure represented corresponds to the pulmonary capillary, a very small blood vessel whose epithelium allows the diffusion of gases.Just before the blood flow in the capillary comes into contact with the alveolus (marked with A in the diagram) the blood has a high content of CO₂, and a low content of  O₂. Once it comes into contact with the alveolus, CO₂ will be released for removal and O₂ will enter, which is the result of alveolus-capillary gas exchange.The pulmonary alveoli are the structure at the end of the bronchial tract, which are located inside the lungs, the main organs of the respiratory system. The lungs are the ones that allow the act of breathing, carrying O₂ to the blood and eliminating CO₂.

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