Pulmonary alveoli are the tiny sacs inside the lungs that fill with air with each breath and facilitate the exchange of gas with the blood. According to HowStuffWorks, the oxygen concentration in the alveoli is high, relative to that of the surrounding tissues, which permits easy passage to the blood.Know More
With each breath, air from outside the body is pulled down the trachea and into the lungs through a branching network of pipes called bronchioles. These bronchioles get progressively smaller until they terminate in the alveolar sacs. The sacs have very thin walls, and they are heavily vascularized, according to HowStuffWorks. Their thin walls permit oxygen to cross over into the blood that is delivered by the pulmonary arteries and permits waste gasses like carbon dioxide to escape into the air in the sac.
Once the exchange takes place, a process that lasts just fractions of a second per cycle, the waste air is expelled with exhalation and the oxygen-rich blood is free to pass back to the heart via the pulmonary veins. This gas-exchange process in the lungs takes place exclusively within the alveoli and is known as external respiration, as opposed to the internal respiration that takes place across the membrane of individual cells, notes HowStuffWorks.Learn more about Organs
Alveoli have a large surface area in order to rapidly exchange gases, which is the primary function of the lungs. There are approximately 300 million alveoli found inside the lungs.Full Answer >
Inhalation is the process of bringing air into the lungs while exhalation is the process of pushing the air out of the lungs. Inhalation helps the body bring in oxygen and exhalation helps the body expel carbon dioxide.Full Answer >
Some of the most vital organs of humans are located in the thoracic cavity, including the lungs and the heart. HowStuffWorks explains that when a person inhales, the diaphragm and muscles between the ribs expand the thoracic cavity to reduce the pressure inside the body to a level that is lower than the pressure of the air outside the body. As a result, the lungs pull air through the body's airways.Full Answer >
The left atrium serves as a vessel for blood coming from the lungs and a pump to deliver blood to other parts of the heart, according to Healthline. Oxygen-rich blood from the lungs goes to the left atrium via the pulmonary vein.Full Answer >