pulmonary vein

Examples of pulmonary vein in the following topics:

• Principal Veins

  • Most veins carry deoxygenated blood from the tissues back to the heart with the exceptions of the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart.
  • The pulmonary veins and venules that run from the lungs to the heart form part of the pulmonary circulatory system and are distinct from other veins in that they carry oxygenated blood.
  • The pulmonary veins are large blood vessels which receive oxygenated blood from the lungs and return it to the left atrium of the heart.
  • There are four pulmonary veins, two from each lung, each of which forms from three to four bronchial veins.
  • In approximately 25% of individuals, the left pulmonary veins may merge into a single vein; the same effect on the right side is only seen in approximately 3% of individuals.

• 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.
  • Oxygenated blood is then returned to the heart via the pulmonary vein.
  • 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 oxygenated blood then leaves the lungs through pulmonary veins, which return it to the left atrium of the heart, completing the pulmonary cycle.
  • Outline the path of pulmonary circulation: blood flow in the lungs

• Great Vessels of the Heart

  • Blood first passes through the pulmonary valve as it is ejected into the pulmonary arteries.
  • The pulmonary veins carry oxygenated blood from the lungs to the left atrium of the heart.
  • Four pulmonary veins enter the left atrium.
  • The right pulmonary veins pass behind the right atrium and superior vena cava while the left pass in front of the descending thoracic aorta.
  • The pulmonary arteries and veins are both considered part of pulmonary circulation.

• Blood Flow in the Heart

  • The heart is a key organ in the circulatory system responsible for the generation of pressure and thus flow throughout the system and pulmonary circulatory systems.
  • The left atrium receives newly oxygenated blood from the lungs through the pulmonary veins, which is passed into the strong left ventricle to be pumped through the aorta to the different organs of the body.
  • The coronary veins remove deoxygenated blood from the heart muscle, returning it through the coronary sinus into the right atrium.
  • Deoxygenated blood is received from the systemic circulation into the right atrium, it is pumped into the right ventricle and then through the pulmonary artery into the lungs.
  • Through association with the alveoli the blood is oxygenated in the lungs and returns to the left atrium through the pulmonary veins, before passing into the left ventricle and being pumped around the body.

• 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 oxygenated blood then leaves the lungs through pulmonary veins, which returns it to the left atrium, completing the pulmonary circuit.
  • Oxygen-rich blood from the lungs leaves the pulmonary circulation when it enters the left atrium through the pulmonary veins.
  • The deoxygenated blood continues through the capillaries which merge into venules, then veins, and finally the venae cavae, which drain into the right atrium of the heart.

• Veins

  • Most carry deoxygenated blood from the tissues back to the heart, but the pulmonary and umbilical veins both carry oxygenated blood to the heart.
  • The deoxygenated blood is taken by veins to the right atrium of the heart, which transfers the blood to the right ventricle, where it is then pumped through the pulmonary arteries to the lungs.
  • In pulmonary circulation the veins return oxygenated blood from the lungs to the left atrium, which empties into the left ventricle, completing the cycle of blood circulation.
  • Veins are classified in a number of ways, including superficial vs. deep, pulmonary vs. systemic, and large vs. small:
  • Pulmonary veins - The pulmonary veins deliver oxygenated blood from the lungs to the heart.

• Blood Supply to the Lungs

  • At the end of systemic circulation, the veins take blood back to the heart through the vena cava.
  • The oxygenated blood then leaves the lungs through pulmonary veins (also contained in the hilium), which return the blood to the left side of the heart, completing the cycle of pulmonary circulation.
  • These blood clots typically originate in the deep veins of the legs (part of systemic circulation) as a result of blood pooling from injury or immobilization.
  • As the veins of the leg are on their way to the right side of the heart, the clots are less likely to break up before they reach pulmonary circulation.
  • Diagram of pulmonary circulation.

• Distribution of Blood

  • Humans have a closed cardiovascular system, meaning that blood never leaves the network of arteries, veins, and capillaries.
  • Humans have a closed cardiovascular system, meaning that the blood never leaves the network of arteries, veins, and capillaries.
  • Blood is circulated through blood vessels by the pumping action of the heart, pumped from the left ventricle through arteries to peripheral tissues and returning to the right atrium through veins.
  • It then enters the right ventricle and is pumped through the pulmonary artery to the lungs and returns to the left atrium through the pulmonary veins.
  • Diagram of pulmonary circulation.

• Operation of Semilunar Valves

  • These valves do not have chordae tendineae, and are more similar to valves in veins than to atrioventricular valves.
  • 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.
  • Describe the operation of the semilunar valves, the aortic and pulmonary valves

• Fetal Circulation

  • Oxygen then diffuses from the placenta to the chorionic villus, an alveolus-like structure, from which it is carried to the umbilical vein.
  • Blood from the placenta is carried to the fetus by the umbilical vein.
  • The branch of the umbilical vein that supplies the right lobe of the liver first joins with the portal vein.
  • Some of the blood entering the right atrium does not pass directly to the left atrium through the foramen ovale, but enters the right ventricle and is pumped into the pulmonary artery.
  • These closures prevent blood from bypassing pulmonary circulation, and therefore allow the neonate's blood to become oxygenated in the newly operational lungs.