1. WHAT ARE THE 3 MAIN DIFFERENCES OF ARTERIES AND VEINS.
Arteries and Veins are essential components in providing blood and oxygen throughout our body, however these components differ from one another in terms of structure and function.
Arteries carry blood away from the heart to the lungs, whereas the veins carry blood to the heart from other body organs.
Arteries carry oxygenated blood, while the veins carries deoxygenated blood.
Arteries have thick walls with muscle tissue as compared to the veins that are made up of thinner walls.

2. How are the arteries and veins similar
Arteries and veins are both found in the circulatory system. Both components are responsible for the transport of blood throughout the body. They are also composed of multiple layers including the tunica intima, tunica media, and tunica externa, that is vital for the strengthening of these messengers of blood transportation. Both are dependent on the heart’s ability to pump blood to the rest of the body organs, however they only differ on the pressure of the body itself. Arteries carry higher blood pressure due to the pumping ability of the heart, while the veins carry low blood pressure.

3. Are veins bigger than arteries?
In terms of diameter, veins are larger and bigger than arteries, due to the fact that the arteries have smaller lumen relative to their walls. These veins carry much more blood volume than the artery itself. Veins have smaller and thinner walls than arteries, making them less stretchy.

4. Two types of veins
– According to healthline.com, veins are characterized by two types; pulmonary and systemic veins. These types of veins are commonly found on circuits on our body. Pulmonary veins carries deoxygenated blood from the heart to the lungs, and once it already contains oxygenated blood, it transports the blood back to the heart making this type of vein unique as a result of it carrying oxygenated blood. In systemic veins, it carries deoxygenated blood from the body to the heart wherein it enters the pulmonary vein for oxygen supply. Most veins are composed of systemic veins.

5. Do veins have valves?
– Veins often have valves, especially in the legs and arms, to help prevent the backflow of blood and ensure that it moves toward the heart. These valves are necessary because veins are under much lower pressure and blood might otherwise flow backward due to gravity.

REFERENCES:
https://www.msdmanuals.com/home/heart-and-blood-vessel-disorders/venous-disorders/overview-of-the-venous-system
https://my.clevelandclinic.org/health/body/23360-veins
https://www.healthline.com/health/venous-system#vein-structure
Guyton, A. C., & Hall, J. E. (2015). Textbook of Medical Physiology (13th ed.). Elsevier Saunders.
Marieb, E. N., & Hoehn, K. (2019). Human Anatomy & Physiology (11th ed.). Pearson.
https://www.osmosis.org/learn/Artery_and_vein_histology
https://www.webmd.com/heart/difference-between-arteries-veins-capillaries
https://www2.victoriacollege.edu/dept/bio/belltutorials/histology%20tutorial/blood%20vessels/histology_of_blood_vessels.html#:~:text=The%20vessel%20walls%20of%20veins,floppy%22%20and%20irregular%20in%20shape.