KNAT Practice Test Question from KNAT Tutor Lesson: Respiratory System
Please see the question below. Scroll down for the correct answer and video explanation.
KNAT Practice Test Answer Explanation
The correct answer is B. Capillaries. Capillaries are blood vessels that form a network around the alveolar sacs to facilitate gas exchange between blood and the lungs. Gas exchange takes place between the air and the blood. This portion includes the lungs, alveoli, and capillaries.
Oxygen from the air enters the body through the respiratory system. But the cardiovascular system circulates oxygen throughout the body via the blood. As shown in the image, alveoli are surrounded by a capillary bed in the lung. This anatomical structure allows blood to absorb oxygen and transport it through a network of blood vessels to cells in various tissues throughout the body. During the process of gas exchange, the blood system absorbs carbon dioxide from cells and carries it to the respiratory system, where it is exhaled from the body.
To learn more about the gas exchange, watch our video explanation below:
[Source: KNAT Tutor Lesson: Respiratory System]