Artery Vs. Vein: What's The Difference? - Healthline

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HealthlineSubscribeWhat’s the Difference Between and Artery and a Vein?

Medically reviewed by Daniel Jennings, PA-C — Written by Scott Frothingham — Updated on October 1, 2024

Types of arteries
Types of veins
Anatomy
FAQ
Takeaway

Arteries and veins are the major blood vessels in your body. Arteries carry blood from the heart, while veins carry blood to the heart.

Arteries and veins are two of the body’s main types of blood vessels. These vessels are channels that distribute blood to the body.

Arteries and veins are part of two closed systems of tubes that begin and end at the heart. These systems of tubes are either:

Pulmonary: Pulmonary arteries transport oxygen-poor blood from the heart’s right ventricle to the lungs, where blood “picks up” oxygen. Pulmonary veins transport oxygen-rich blood back to the heart’s left atrium.
Systemic: Systemic arteries carry oxygen-rich blood from the heart’s left ventricle to the tissues in all parts of the body. Systemic veins then return oxygen-poor blood back to the heart’s right atrium.

What are the different types of arteries?

There are two main types of arteries: elastic and muscular. A third type — arterioles — are smaller and branch off from arteries.

Elastic arteries, also called conducting arteries or conduit arteries, have a thick middle layer that allows them to stretch in response to each pulse of the heart. These include arteries near the heart, like the aorta and pulmonary arteries.

Muscular (distributing) arteries are medium-sized. They draw blood from elastic arteries and contain more smooth muscle in the middle layer. These include arteries further away from the heart, like the brachial and femoral arteries.

What are the different types of veins?

There are several ways of classifying systemic veins. For example, the veins in the legs can be grouped into three categories:

Deep veins are located within muscle tissue. They have a corresponding artery nearby.
Superficial veins are closer to the skin’s surface. They don’t have corresponding arteries.
Perforating veins connect deep and superficial veins.

Anatomy of veins and arteries

The walls of veins and arteries are both made up of three layers:

Outer: Tunica adventitia (tunica externa) is the outer layer of a blood vessel, including arteries and veins. It’s mostly composed of collagen and elastic fibers. These fibers enable the veins and arteries to stretch a limited amount. They stretch enough to be flexible while maintaining stability under the pressure of blood flow.
Middle: The middle layer of the walls of arteries and veins is called the tunica media. It’s made of smooth muscle and elastic fibers. This layer is thicker in arteries and thinner in veins.
Inner: The inner layer of the blood vessel wall is called tunica intima. This layer is made of elastic fiber and collagen. Its consistency varies based on the type of blood vessel.

Unlike arteries, veins contain valves. Veins need valves to keep the blood flowing toward the heart. These valves are particularly important in the legs and arms. They fight gravity to prevent the backflow of blood.

Valves in the veins can burst due to trauma, such as an injury, or increased blood pressure. This is known as venous insufficiency and can result in swelling that is difficult to treat.

Arteries don’t need valves because the pressure from the heart keeps the blood flowing through them in one direction.

Frequently asked questions

Why is blood taken from veins and not arteries?

Healthcare professionals prefer to draw blood from veins because they tend to be more superficial (closer to the skin), have thinner walls, and have fewer nerves, meaning they would cause less pain.

What happens if you stick an artery instead of a vein?

An accidental arterial puncture isn’t common but could cause bleeding and bruising. The National Health Service notes that the bruising could look severe and linger for weeks but will eventually go away.

Arteries also have different concentrations of certain electrolytes and oxygen. This can result in falsely abnormal test results, requiring retesting.

Why are veins blue?

Oxygen-poor blood in your veins isn’t actually blue. The blue appearance has to do with the scattering of light and which colors are absorbed by the blood and our skin. In the end, we mostly see reflected blue light.

Takeaway

The key difference between arteries and veins is that arteries carry blood away from your heart, while veins carry blood to your heart. In most cases, arteries carry oxygen-rich blood, and veins carry oxygen-poor blood, but that doesn’t apply during the pulmonary circuit between your heart and lungs.

Other differences exist in the anatomy of arteries and veins due to their different functions. Veins have thinner walls. They also have valves to prevent the backward flow of blood. The higher blood pressure in the arteries keeps the blood flowing in the right direction.

How we reviewed this article:

SourcesHistoryHealthline has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical journals and associations. We only use quality, credible sources to ensure content accuracy and integrity. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.

Arterial puncture. (n.d.).https://www.blood.co.uk/the-donation-process/further-information/arterial-puncture/
Classification & structure of blood vessels. (n.d.).https://training.seer.cancer.gov/anatomy/cardiovascular/blood/classification.html
DePopas E, et al. (2018). Varicose veins and lower extremity venous insufficiency.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5886767/
In brief: How does the blood circulatory system work? (2023).https://www.ncbi.nlm.nih.gov/books/NBK279250/
Patel SK, et al. (2024). Venous insufficiency.https://www.ncbi.nlm.nih.gov/books/NBK430975/
Srikanth KK, et al. (2023). Phlebotomy.https://www.ncbi.nlm.nih.gov/books/NBK574569/
Tucker WD, et al. (2023). Anatomy, blood vessels.https://www.ncbi.nlm.nih.gov/books/NBK470401/
Van Leeuwen SR, et al. (2018). Elucidating the contribution of Rayleigh scattering to the bluish appearance of veins.https://www.spiedigitallibrary.org/journals/journal-of-biomedical-optics/volume-23/issue-02/025001/Elucidating-the-contribution-of-Rayleigh-scattering-to-the-bluish-appearance/10.1117/1.JBO.23.2.025001.full

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Medically reviewed by Daniel Jennings, PA-C — Written by Scott Frothingham — Updated on October 1, 2024

Tag » What Artery Carries Deoxygenated Blood

Artery Vs. Vein: What's The Difference? - Healthline

What are the different types of arteries?

What are the different types of veins?

Anatomy of veins and arteries

Frequently asked questions

Why is blood taken from veins and not arteries?

What happens if you stick an artery instead of a vein?

Why are veins blue?

Takeaway

How we reviewed this article:

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