What organ is associated with nervous tissue?

The brain is the organ most closely associated with nervous tissue because it is the central hub of the nervous system. Nervous tissue is composed primarily of neurons, which are specialized cells that transmit electrical signals throughout the body. The brain not only contains a vast number of neurons but also glial cells, which support and protect the neurons.

Other organs listed, such as the liver, heart, and kidneys, primarily consist of other types of tissues—like epithelial, connective, and muscle tissues. While the heart does contain some nerve cells that help control its rhythm and rate, it does not serve as a central processing unit for the nervous system like the brain does. Therefore, when considering which organ is fundamentally linked to nervous tissue, the brain is the clear answer due to its role in processing information, coordinating responses, and facilitating communication within the body.