Inductive definition of CW complexes. If the largest dimension of any of the cells is n, then the CW complex is said to have dimension n. If there is no bound to the cell dimensions then it is said to be infinite-dimensional. The n-skeleton of a CW complex is the union of the cells whose dimension is at most n.
Deoxygenated blood enters the right atrium through three major veins: the superior and inferior vena cava and the coronary sinus. The superior vena cava returns all of the blood to the heart from tissues superior to the heart in the head, neck, arms and upper thorax.
The aorta carries oxygenated blood to the body. The pulmonary artery carries deoxygenated blood to the lungs and it is the only artery to carry deoxygenated blood. There are two veins associated with the heart. The vena cava, or great vein, carries deoxygenated blood back to the heart from the body. The pulmonary vein is the only vein to carry oxygenated blood which is on its way to the heart from the lungs.The right atrium and ventricle only has deoxygenated blood while the left atrium and ventricle contains oxygenated blood.