Pulmonary vein
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The pulmonary veins are the veins that transfer oxygenated blood from the lungs to the heart. The largest pulmonary veins are the four main pulmonary veins, two from each lung that drain into the left
Computed tomography of a normal lung, with different levels of pulmonary veins.
Bronchial anatomy
Cardiac cycle
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The cardiac cycle is the performance of the human heart from the beginning of one heartbeat to the beginning of the next. It consists of two periods: one during which the heart muscle relaxes and refi
The cycle diagram depicts one heartbeat of the continuously repeating cardiac cycle, namely: ventricular diastole followed by ventricular systole, etc.—while coordinating with atrial systole followed by atrial diastole, etc. The cycle also correlates to key electrocardiogram tracings: the T wave (which indicates ventricular diastole); the P wave (atrial systole); and the QRS 'spikes' complex (ventricular systole)—all shown as color purple-in-black segments.
