You do it this way; the shift in perspective can bewilder the reader. Consistency is the chief virtue here. There is, of course, a difference between a process essay that tells readers how to do something and a process essay that describes the process by which something gets done by someone else or by nature.here is, of course, a difference between a process essay that tells readers how to do something and a process essay that describes the process by which something gets done by someone else or by nature.
In the human heart, the pulmonary trunk (pulmonary artery or main pulmonary artery) begins at the base of the right ventricle. It is short and wideâapproximately 5 centimetres (2.0 in) in length and 3 centimetres (1.2 in) in diameter.
The pulmonary arteries carry blood to smaller arterioles and on to the vast capillary beds of the lungs where carbon dioxide is released and oxygen is obtained from the air in the alveoli of the lungs. These capillaries converge into larger venules, which further converge to form the left and right pulmonary veins.he pulmonary arteries and pulmonary veins provide vital but short distance blood flow between the heart and the lungs. Exiting the heart from the right ventricle, deoxygenated blood flows into the large pulmonary trunk before splitting at the left and right pulmonary arteries.