What is arteries

Key Takeaways Key Points Elastic arteries include the largest arteries in the body, those closest to the heart. They give rise to medium-sized vessels known as muscular, or distributing, arteries. Elastic arteries differ from muscular arteries both in size and in the relative amount of elastic tissue contained within the tunica media.

Arterial elasticity gives rise to the Windkessel effect, which helps to maintain a relatively constant pressure in the arteries despite the pulsating nature of blood flow.

Key Terms elastic arteries : An artery with a large number of collagen and elastin filaments, giving it the ability to stretch in response to each pulse. The Aorta Due to position as the first part of the systemic circulatory system closest to the heart and the resultant high pressures it will experience, the aorta is perhaps the most elastic artery, featuring an incredibly thick tunica media rich in elastic filaments.

Muscular Arteries Distributing arteries are medium-sized arteries that draw blood from an elastic artery and branch into resistance vessels. Learning Objectives Distinguish muscular arteries from elastic arteries. Key Terms muscular arteries : Medium-sized arteries that draw blood from an elastic artery and branch into resistance vessels, including small arteries and arterioles.

It is readily visualized with light microscropy in sections of muscular arteries. Anastomoses A circulatory anastomosis is a connection or looped interaction between two blood vessels. Learning Objectives Explain the function of arterial anastomoses. Key Takeaways Key Points Anastomoses occur normally in the body in the circulatory system, serving as backup routes for blood flow if one link is blocked or otherwise compromised.

Anastomoses between arteries and between veins result in a multitude of arteries and veins, respectively, serving the same volume of tissue. Pathological anastomoses result from trauma or disease and are referred to as fistulae. Key Terms circulatory anastomosis : A connection between two blood vessels, such as between arteries arterio-arterial anastomosis , between veins veno-venous anastomosis , or between an artery and a vein arterio-venous anastomosis.

Arterioles An arteriole is a small diameter blood vessel in the microcirculation system that branches out from an artery and leads to capillaries.

Learning Objectives Explain the function of arterioles. Key Takeaways Key Points Arterioles have muscular walls and are the primary site of vascular resistance, which reduces the pressure and velocity of flow for gas and nutrient exchange to occur within the capillaries. Arterioles are innervated and can also respond to other circulating factors to regulate their caliber.

Key Terms microcirculation : The flow of blood through the smallest vessels: arterioles, capillaries, and venules. Capillaries Capillaries, the smallest blood vessels in the body, are part of the microcirculation.

Learning Objectives Describe the structure and function of capillaries. Capillaries connect arterioles and venules and enable the exchange of water, oxygen, carbon dioxide, and many other nutrients and waste substances between blood and surrounding tissues. There are three main types of capillaries: continuous, fenestrated, and sinusoidal. Key Terms capillary : Any of the small blood vessels that connect arteries to veins.

Licenses and Attributions. Select personalised content. Create a personalised content profile. Measure ad performance. Select basic ads. Create a personalised ads profile. Select personalised ads. Apply market research to generate audience insights. Measure content performance. Develop and improve products. List of Partners vendors. Arteries are blood vessels that carry blood away from the heart to the rest of the body.

They are shaped like tubes and branch into arterioles to reach the organs and tissues. The pumping contractions of the heart propel the blood through the arteries. The main artery of the systemic circulation is the aorta.

It is attached to the left ventricle of the heart and carries oxygenated blood. The aorta branches into arteries that go to different organs and parts of the body. You can feel your pulse in an artery such as the carotid artery in the neck or the radial artery in the wrist.

The pulmonary artery differs from the others in that it is attached to the heart's right ventricle and carries blood that is poor in oxygen to the lungs.

Damaged or narrowed arteries can lead to the body not getting an adequate blood supply, which can put you at risk for things such as heart attack or stroke. But what does that mean? Checking your blood pressure at home with a manual or automated device can help you monitor your health between doctor visits.

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Blood clotting is a good thing, because it can stop you from bleeding. The middle layer, the tunica media , is primarily smooth muscle and is usually the thickest layer. It not only provides support for the vessel but also changes vessel diameter to regulate blood flow and blood pressure. The outermost layer, which attaches the vessel to the surrounding tissue, is the tunica externa or tunica adventitia.

This layer is connective tissue with varying amounts of elastic and collagenous fibers. The connective tissue in this layer is quite dense where it is adjacent to the tunic media, but it changes to loose connective tissue near the periphery of the vessel. 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.

The primary function of capillaries is the exchange of materials between the blood and tissue cells. Capillary distribution varies with the metabolic activity of body tissues. Tissues such as skeletal muscle , liver , and kidney have extensive capillary networks because they are metabolically active and require an abundant supply of oxygen and nutrients. Other tissues, such as connective tissue, have a less abundant supply of capillaries.