No valves exist between the anterior vena cava and the heart, and the heartbeat tends to cause movement within this blood vessel. Another vessel, the posterior vena cava, carries blood from the lower half of the body to the heart.
The 2016 Hereford, Texas, population is 15,021. There are 2,447 people per square mile (population density).
Harris County is one of 10 counties in the Houston region, which is located on the upper Gulf coastal plain of Texas. Harris County's population as of July 1, 2013 was 4,336,853, the largest county in Texas by population. Houston is the county seat. Other towns include Pasadena, Baytown and Bellaire.