Arteries and their Function
Arteries are blood vessels that carry blood away from the heart to various parts of the body. They are responsible for transporting oxygenated blood, nutrients, and hormones to tissues and organs. However, not all arteries carry oxygenated blood.

Assertion and Reason Analysis

Assertion (a): Arteries always carry oxygenated blood.

Reason (r): Arteries transport blood from the heart to different parts of the body.

Explanation
- Arteries and Oxygenated Blood: While it is true that arteries carry oxygenated blood from the heart to the body, there is an exception. The pulmonary artery is an artery that carries deoxygenated blood from the heart to the lungs for oxygenation. Once the blood is oxygenated in the lungs, it returns to the heart through the pulmonary veins.
- Arterial Function: Arteries play a crucial role in the circulatory system by delivering oxygenated blood to tissues and organs. They have thick muscular walls that help maintain blood pressure as blood is pumped from the heart.
- Transportation of Nutrients: In addition to oxygen, arteries also transport nutrients such as glucose, amino acids, and fatty acids to cells throughout the body. This ensures proper nourishment and functioning of tissues.
- Reasoning: The reason provided is accurate in stating that arteries transport blood from the heart to different parts of the body. This function is essential for maintaining the overall health and vitality of the body's organs and systems.
In conclusion, while arteries primarily carry oxygenated blood away from the heart, the pulmonary artery is an exception as it carries deoxygenated blood to the lungs. Understanding the role of arteries in the circulatory system is crucial for comprehending their essential function in maintaining overall health.