From the vena cava (superior and inferior), the blood enters the heart (right atrium), is pumped into the right ventricle, and then pumped into the lungs (through the Pulmonary Arteries), where carbon dioxide is exchanged for oxygen.
Harlan, Iowa. Harlan is a city in Shelby County, Iowa, United States, along the West Nishnabotna River. The population was 5,106 at the 2010 census. It is the county seat of Shelby County.
The most populous city in Iowa is Des Moines, with over 210,000 residents, followed by Cedar Rapids (130,405) and Davenport (102,582). Iowa now has a predominantly urban population concentrated in these areas, with 61% of the total population living in urban areas by 2000.