Gas exchange occurs in which type of tissue?

Gas exchange primarily occurs in capillaries, which are the smallest blood vessels in the body. These thin-walled vessels are ideally suited for the exchange of gases because of their structure. The walls of capillaries are composed of a single layer of endothelial cells, allowing for easy diffusion of oxygen and carbon dioxide between the blood and surrounding tissues.

In the lungs, for example, oxygen from the inhaled air diffuses into the blood through the capillary walls, while carbon dioxide, a waste product of metabolism, diffuses from the blood into the alveoli to be exhaled. This process is vital for maintaining the body's oxygen supply and removing carbon dioxide, a byproduct of cellular respiration.

The other types of tissues listed do not perform gas exchange. Arteries and veins are designed to transport blood throughout the body but are not structured for direct gas exchange. Nerves are involved in transmitting electrical signals and have no role in the movement of gases. Thus, capillaries are specifically adapted for the efficient exchange of gases at the cellular level.