Atrial fibrillation is a heart condition in which the atria of the heart beat in an abnormal rhythm because of disorganized electrical activity. It often starts with short periods of abnormal heart action which eventually become longer or even continuous. Often, these episodes are asymptomatic,...
Two major phases can be distinguished during breathing, namely inspiration and expiration. During inspiration, the diaphragm is dragged down and the thorax and lungs expand. This sucks air into the lungs. During expiration, the muscles of the thorax and the diaphragm contract and push out...
An air embolism occurs when a blood vessel is blocked by one or more bubbles of air or gas. Under normal circumstances, the CO2 that is produced in the body is transported by the blood in the superior and inferior vena cava to the heart,...
The blood circulation of the human body can be broadly divided into two sections: pulmonary circulation; systemic circulation. The pulmonary circulation involves the pulmonary artery which transports deoxygenated blood from the body towards the lungs. In the alveoli, the CO2 in the deoxygenated blood is...
The capillaries are the smallest blood vessels in the human body. These blood vessels are only 5 to 10 micrometers in diameter and their walls consist of only one layer of endothelial cells. This thin wall is necessary because the capillaries are the site of...
When O2 is used by cells to produce energy, CO2 is created as a byproduct. This is handed off to the bloodstream to be carried back to the lungs and released during expiration. But CO2 is acidic, which means that it lowers the pH of...