Pulmonary circulation

Or less than the pulmonary circulation circuit of the part of the circulatory system is referred to, which takes the blood from the heart to the lungs and returns again.

The deoxygenated blood is drained from the right ventricle ( ventricle ) on the pulmonary trunk ( pulmonary trunk ). This tribe is divided into the right and left pulmonary artery ( pulmonary artery ), which branch out in the respective lung. There, the gas exchange, the blood is carbon dioxide ( CO2), and increases oxygen ( O2) to ( by diffusion ).

The now oxygen-rich blood flows across multiple pulmonary veins ( pulmonary veins ) back to the heart, more to the left atrium.

In addition to the pulmonary arteries, the lung is supplied by bronchial arteries that supply the lungs with oxygen-rich blood from the disposal of the aorta.

When the fetus is from the pulmonary trunk a connection to the aorta, the ductus arteriosus. Likewise, an opening between the right and left atrium, the foramen ovale exists. These two formations include the pulmonary circulation largely short, the lung is not ventilated so the fetus.

Pulmonary circulation at a glance

  • Transport of " oxygen-poor " blood
  • Transport of " oxygenated " blood

Right atrium → tricuspid valve → right ventricle → pulmonary valve → left / right pulmonary artery → pulmonary artery → capillary bed of the alveoli → pulmonary veins → left / right pulmonary vein → left atrium → mitral valve → left ventricle

Pulmonary Vascular resistance

Pulmonary vascular resistance (PVR) of the pulmonary circulation is as large as the total peripheral resistance of the systemic circulation only about 1/10. Therefore, the blood pressure in the pulmonary circulation ( 20/8 mm Hg) is significantly lower than in the blood circuit ( 120/80 mmHg). A decrease of the O2 concentration in the alveoli ( = hypoxia) leads to vasoconstriction of pulmonary vessels in the lung sections, and thus corresponding to an increase in PVR. This mechanism is referred to as hypoxic pulmonary vasoconstriction or Euler Liljestrand mechanism. It is used to reduce the blood flow to poorly ventilated lung areas and so divert the pulmonary blood flow to better ventilated lung areas. This decreases the proportion of the blood, which, although it flows through the lungs there but not loaded with oxygen ( oxygenated ) is (reduction of shunt flow ). The neural regulation of the pulmonary circulation is only of minor importance. The PVR thus undergoes little sympathetic ( = vasoconstriction ) and parasympathetic regulation.

Sources and links

  • Information to the bloodstream ( with lung and systemic circulation )
  • Information on the cardiovascular system ( small and large circulation)
  • Circulatory system
  • Cardiology
Bronchial artery Foramen ovale (heart) Euler–Liljestrand mechanism
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