Barstow is a city in San Bernardino County, California, United States. The population was 22,639 at the 2010 census, up from 21,119 at the 2000 census. Barstow is located 55 miles (89 km) north of San Bernardino. Barstow is a major transportation center for the Riverside-San Bernardino metropolitan area. Several major highways including Interstate 15 and Interstate 40 converge in the city. It is the site of a large rail classification yard, belonging to the BNSF Railway.
1 Capillaries are the smallest blood vessels. 2  They connect to the arteries and the veins. 3  Capillaries are extremely small tubes that average 6 to 8 micron in size; they are too small to see without a microscope.xygen rich blood is pumped out of the left ventricle of the heart into the aorta, which is the largest artery in the body. The oxygen rich blood travels through the aorta into smaller arteries. The capillaries sit between the arteries and the veins, connecting the two together and acting as an exchange stop.
Simply the heart, a big muscle, is connected to a series of tubes, the arteries and the veins, which carry blood to the various parts of the body. Arteries carry the blood away from the heart, while veins bring blood back to the heart. The arteries are connected to the veins via very small vessels called capillaries. Electrical and chemical signals to the heart cause it to pump the blood into the arteries. Further, a number factors can cause the blood vessels to expand (dilate) or contract. In doing so they can increase or decrease the amount of effort the heart needs to put forth to deliver the blood.