Final answer:
Arteries function to distribute oxygenated blood from the heart to the body, with major systemic arteries including the aorta and carotid arteries. Veins, with the largest being the superior and inferior vena cava, return deoxygenated blood to the heart and have valves to prevent backflow. Capillaries allow for the exchange of gases and nutrients between blood and tissues.
Step-by-step explanation:
Functions of Arteries and Structure of Veins
Arteries are blood vessels that carry oxygenated blood away from the heart to the body's tissues. The function of arteries is to distribute oxygen and nutrients carried in the blood to cells throughout the body. They have thick walls composed of three layers: an inner layer known as the intima, a middle layer of smooth muscle called the media, and an outer layer of connective tissue called the adventitia. These layers allow arteries to withstand and regulate the high pressure of blood pumped from the heart.
Major Systemic Arteries
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- Aorta
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- Carotid arteries
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- Subclavian arteries
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- Common iliac arteries
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- Renal arteries
Structure and Function of Veins
Veins are vessels that carry deoxygenated blood back to the heart. Their walls are thinner and less elastic than those of arteries. They are equipped with venous valves that prevent the backflow of blood, aiding its return to the heart, especially from the extremities. The two largest veins in the body are the superior and inferior vena cava.
Role of Capillaries in Circulation
Capillaries are the smallest blood vessels where the exchange of gases, nutrients, and waste products occurs between blood and tissues. Their walls are only one cell thick, allowing for this exchange through the process of diffusion. Capillaries connect arterioles and venules, completing the circuit of circulation.