A vein is a blood vessel that carries blood toward the heart. There are four main types of veins: pulmonary and systemic, and superficial and deep.Know More
About.com Biology states that each of the four types of veins is unique. Pulmonary veins are responsible for transporting oxygen-rich blood from the lungs to the left atrium of the heart. Systemic veins collect oxygen-poor blood from all parts of the body and return it to the right atrium of the heart. Superficial veins are close to the surface of the skin whereas deep veins are located inside muscle tissue. Deep veins are usually located near a corresponding artery with the same name, but superficial veins are not.
Veins can be as small as 1 millimeter or as large as 1.5 centimeters in diameter. About.com Biology explains that part of the body's system of veins is comprised of small venules that receive oxygen-poor blood from capillaries. The venules transport blood to systems of larger veins, which eventually lead to the superior vena cava or the inferior vena cava. The venae cavae lead to the right atrium of the heart, where the blood is returned to flow through the cardiac cycle.Learn more about Blood
The dorsal blood vessel is part of the circulatory system of the earthworm that carries blood to the front of its body. It is a single structure that runs along the back of the worm's body.Full Answer >
The capillaries are responsible for the interchange of oxygen, carbon dioxide, water, nutrients and waste products between blood and surrounding tissues. The capillaries are the smallest of the blood vessels.Full Answer >
A blood vessel may pop due to injury, bruising, allergic reaction, blood infection or an autoimmune disorder, according to Healthline. A tiny amount of blood flows from the vessel into the surrounding areas when a blood vessel bursts. The blood usually appears close to the skin’s surface.Full Answer >
Blood enters the heart through two major veins at the right atrium before going to the right ventricle and to the lungs. When blood returns from the lungs, it goes into the left atrium and the left ventricle before leaving the heart to go to the rest of the body through the aorta, according to Cleveland Clinic.Full Answer >