Why arteries thicker than veins

The Circulatory System has, at the centre of it, the Heart. It pumps blood out at high pressure so that it can reach all the parts of the body quickly. To withstand the pressure of the blood coming out from the heart, arteries need thick walls. The returning blood in the veins is under low er pressure. Because of the lower pressure, vein walls are thinner. However, veins also have one-way stop valves to keep blood from flowing backwards.

The link below has, aside from a wealth of additional information, a 30 second animation on how this works. Why are arteries thicker than veins? Sep 28, To withstand the high pressure of the outflow of blood from the Heart. Explanation: The Circulatory System has, at the centre of it, the Heart.

People who smoke often have cold hands and feet. What might explain this condition in terms of During this, the blood is released or pumped from the blood at high pressure so that the blood flows through to different organs and reaches the extreme points of the body. To withstand this high pressure and maintain a significant pressure within themselves, the arteries have thick walls.

This is not true for the veins as the pressure in the veins is less as there is no pumping of blood into the veins, unlike the arteries. The structure of the arterial walls is explained in detail below. This explanation also provides the answer to the question - Why do arteries have thick walls? Arteries, as it is very well known, carry oxygenated blood from the heart to the different parts of the body.

The arteries that actually carry the blood from the heart to different organs is known as the systemic artery. In exception, there are two arteries: the pulmonary artery and umbilical artery which carry the blood to the organs that oxygenate the blood.

The walls of the arteries can be divided into three layers. Those are from outside to inside: i Tunica externa, ii Tunica media and, iii Tunica intima. The first layer Tunica externa or also known as tunica adventitia is composed of collagen fibres and elastic tissue. This layer does not have a well-defined boundary as we go towards the lumen of the artery that carries the blood.

Normally, it is considered when it reaches or touches the connective tissue layer or the Tunica media. Tunica media or only media is made up of smooth muscle cells , elastic connective tissue and collagen fibres. Following, the Tunica media is the Tunica intima or commonly known as intima is the last layer and the layer which is directly in contact with the blood. This layer is completely made up of the endothelial cells.

The sectioning of the arteries is shown below in the given schematic diagram. The elastic layer aids the arteries in providing flexibility for bending and fitting through the places. It is this portion of the Tunica media that creates the difference of the thickness between arteries and veins, arteries and other blood vessels.

The presence of more elastic cells and smooth muscle cells in the media of arteries than the veins or any other blood vessels. The main reason is that arteries have a higher blood pressure than observed by other parts of the circulatory system. So, the answer to the question as to why are arteries thicker than veins is that because arteries have higher blood pressure.