pulmonary artery

Examples of pulmonary artery in the following topics:

• Blood Flow in the Lungs

  • The pulmonary circulatory system is the portion of the cardiovascular system in which oxygen-depleted blood is pumped away from the heart to the lungs via the pulmonary artery.
  • From the right ventricle of the heart, blood is pumped through the pulmonary semilunar valve into the left and right pulmonary arteries (one for each lung) and travels through the lungs.
  • The pulmonary arteries carry deoxygenated blood to the lungs, where they release carbon dioxide and pick up oxygen during respiration.
  • The pulmonary arteries divide into thin-walled capillaries closely associated with the alveoli, small air sacs in the lungs where gas exchange occurs.
  • The oxygenated blood then leaves the lungs through pulmonary veins, which return it to the left atrium of the heart, completing the pulmonary cycle.

• Operation of Semilunar Valves

  • The semilunar valves are located at the connection between the pulmonary artery and the right ventricle, and the aorta and the left ventricle.
  • When the atrioventricular valves shut, the semilunar valves open, forcing blood into the aorta and pulmonary artery.
  • The pulmonary valve (sometimes referred to as the pulmonic valve), which also has three cusps, separates the right ventricle from the pulmonary artery.
  • Similar to the aortic valve, the pulmonary valve opens in ventricular systole, when the pressure in the right ventricle exceeds the pressure in the pulmonary artery.
  • When ventricular systole ends, pressure in the right ventricle drops rapidly, and the pressure in the pulmonary artery forces the pulmonary valve to close.

• Great Vessels of the Heart

  • The pulmonary arteries carry deoxygenated blood from the right ventricle into the alveolar capillaries of the lungs to unload carbon dioxide and take up oxygen.
  • The short, wide vessel branches into the left and right pulmonary arteries that deliver deoxygenated blood to the respective lungs.
  • Blood first passes through the pulmonary valve as it is ejected into the pulmonary arteries.
  • The pulmonary arteries and veins are both considered part of pulmonary circulation.
  • Diagram of pulmonary circulation.

• Systemic and Pulmonary Circulation

  • From the right ventricle, blood is pumped through the pulmonary valve and into the pulmonary artery.
  • The pulmonary artery splits into the right and left pulmonary arteries and travel to each lung.
  • The aorta arches and branches into major arteries to the upper body before passing through the diaphragm, where it branches further into arteries which supply the lower parts of the body.
  • The arteries branch into smaller arteries, arterioles, and finally capillaries.
  • Diagram of pulmonary circulation.

• Blood Supply to the Lungs

  • Bronchial circulation (by the bronchial arteries) supplies blood to the tissues of the bronchi and the pleura, and is considered part of systemic circulation.
  • After blood fills in the right ventricle, it contracts and pumps the blood through the pulmonary valve, and into the pulmonary arteries.
  • There are two pulmonary arteries (one for each lung) that bring the deoxygenated blood to the lungs through the hilium.
  • The arteries branch into the capillaries of the alveoli.
  • When the clot reaches the pulmonary artery, it obstructs the flow of blood into the lung, which causes the alveoli in the effected lung to die as a result.

• Heart Valve Disorders

  • Pulmonary and tricuspid valve diseases are right-side heart diseases.
  • Pulmonary valve diseases are the least common heart valve disease in adults.
  • The most common types of pulmonary valve diseases are: pulmonary valve insufficiency, pulmonary valve incompetence, and pulmonary valve regurgitation.
  • Complications arise when the flow of blood is obstructed from leaving the right ventricle and making its way into the pulmonary artery, or once blood is in the pulmonary artery, the blood has the ability to flow back into the right ventricle.
  • When blood has a difficult time making its way from the right ventricle into the pulmonary artery due to the pulmonary valve area being too narrow, deformed in some capacity (e.g., one of the leaflets of the valve is too thick, misshaped, or doesn't separate from another leaflet), or the vessel above or below the valve being deformed in such a way as to prevent the proper flow of blood, the term pulmonary valve stenosis is used.

• Artery Function

  • Arteries are blood vessels that carry blood away from the heart under pressure.
  • This blood is usually oxygenated, with the exception of that in the pulmonary artery, which carries deoxygenated blood to the lungs.
  • As with veins, arteries are comprised of three layers: the tunicae intima, media, and externa.
  • Larger arteries are typically elastic and smaller arteries are more likely to be muscular.
  • Distinguish the function of the arterial system from that of venous system

• Elastic Arteries

  • Elastic arteries contain larger numbers of collagen and elastin filaments in their tunica media than muscular arteries do, giving them the ability to stretch in response to each pulse.
  • Elastic arteries include the largest arteries in the body, those closest to the heart, and give rise to the smaller muscular arteries.
  • The pulmonary arteries, the aorta, and its branches together comprise the body's system of elastic arteries.
  • In elastic arteries, the tunica media is rich with elastic and connective tissue.
  • The aorta makes up most of the elastic arteries in the body.

• Structures of the Heart

  • After it is filled, the right ventricle pumps the blood through the pulmonary arteries to the lungs for re-oxygenation.
  • After blood passes through the pulmonary arteries, the right semilunar valves close, preventing the blood from flowing backwards into the right ventricle.
  • Atherosclerosis is the blockage of an artery by the buildup of fatty plaques.
  • Blood then enters the pulmonary circuit and is oxygenated by the lungs.
  • From the pulmonary circuit, blood re-enters the heart through the left atrium.

• Pulmonary Edema

  • Pulmonary edema is fluid accumulation in the air spaces and parenchyma of the lungs.
  • It is due to either failure of the left ventricle of the heart to adequately remove blood from the pulmonary circulation ("cardiogenic pulmonary edema") or an injury to the lung parenchyma or vasculature of the lung ("noncardiogenic pulmonary edema").
  • Low oxygen saturation and disturbed arterial blood gas readings support the proposed diagnosis by suggesting a pulmonary shunt.
  • In the case of cardiogenic pulmonary edema, urgent echocardiography may strengthen the diagnosis by demonstrating impaired left ventricular function, high central venous pressures, and high pulmonary artery pressures.
  • Interstitial and alveolar pulmonary edema with small pleural effusions on both sides.