1. What are the three main differences between arteries and veins?
Arteries carry blood away from the heart, and veins carry blood towards the heart. With the exception of pulmonary blood vessels, arteries carry oxygenated blood and veins carry deoxygenated blood. Arteries have thick walls with muscle tissue. Veins have thinner walls and use valves to keep your blood flowing.

2. How are arteries and veins similar?
Arteries and veins are similar in that they are both blood vessels that transport blood throughout the body and have three layers in their walls. Arteries carry blood away from the heart to the rest of the body. Veins push blood back to your heart. You have a complex system of connecting veins and arteries throughout your body.

3. Why are veins thinner than arteries?
Veins have much thinner walls than do arteries, largely because the pressure in veins is so much lower. veins carry blood at a lower pressure and don’t need to be as strong to handle the pressure. Veins can widen (dilate) as the amount of fluid in them increases.

4. Are veins bigger than arteries?
No, your arteries are thicker and stretchier to be able to handle the higher pressure of blood moving through them. Your veins are thinner and less stretchy. This structure helps veins move higher amounts of blood over a longer time than arteries.

5. What are the two types of veins?

Types of veins
* Pulmonary veins. The pulmonary circuit carries deoxygenated blood from your heart to your lungs. Pulmonary Veins transport oxygen-rich blood from your lungs to your heart. Each lung features two sets of pulmonary veins, a left and right one.
* Systemic veins. The systemic circuit carries deoxygenated blood from the rest of the body back to your heart, where it then enters the pulmonary circuit for oxygen. Systemic Veins are located all throughout the body from your arms to your legs and transport oxygen-depleted blood back to your heart.

Sources:

https://www.webmd.com/heart/difference-between-arteries-veins-capillaries#:~:text=Arteries%20carry%20blood%20away%20from,to%20keep%20your%20blood%20flowing.

https://www.healthline.com/health/artery-vs-vein#:~:text=reflected%20blue%20light.-,Takeaway,flowing%20in%20the%20right%20direction.

https://www.medicalnewstoday.com/articles/artery-vs-vein

https://my.clevelandclinic.org/health/body/23360-veins#:~:text=Veins%20and%20arteries%20share%20this,thick%20to%20handle%20the%20pressure.

https://www.healthline.com/health/venous-system

https://www.britannica.com/story/whats-the-difference-between-veins-and-arteries