It is also very common to mistake veins with arteries, which are in fact the two main types of blood vessels in our bodies, along with capillaries. In order to define the differences, it is important to know that veins are blood vessels that return the less oxygenated blood, full with waste products from all the different process in the body, back to the heart where toxins and harmful elements can be excreted.
Veins can vary in type and size depending on their functions, but they mainly divide into four categories. They can be:
Deep: Located into the muscle tissue. They have an artery counterpart that carries the oxygenated blood.
Superficial: Smaller and closer to the skin with no complementary artery.
Pulmonary: Connect both right and left lungs back to the heart.
Systemic: Transport deoxygenated blood from the different organs in the body. They spread from the neck to the bottom of the legs.