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.
The walls of veins have the same three layers as the arteries. Although all the layers are present, there is less smooth muscle and connective tissue. This makes the walls of veins thinner than those of arteries, which is related to the fact that blood in the veins has less pressure than in the arteries.Because the walls of the veins are thinner and less rigid than arteries, veins can hold more blood.apillaries. Capillaries, the smallest and most numerous of the blood vessels, form the connection between the vessels that carry blood away from the heart (arteries) and the vessels that return blood to the heart (veins).