Efferent nerves are responsible for sending messages to which of the following?

Efferent nerves play a crucial role in the nervous system by transmitting signals away from the central nervous system to various parts of the body. Specifically, they are responsible for sending messages to muscles and glands, enabling motor functions and the regulation of bodily processes such as hormone release and other glandular activities.

When the brain or spinal cord processes information and decides on a response, efferent nerves carry that response to the target muscles, initiating movement, or to the glands, prompting secretion. This pathway is essential for reflexes, voluntary movements, and various functions that require organ and muscle coordination.

In contrast, sensory organs are connected to afferent nerves, which transmit signals towards the central nervous system. The brain receives input from both afferent and efferent pathways but is not the direct target of efferent nerves. The spinal cord also plays a role in the nervous system but primarily acts as a conduit for signals rather than a target for the messages sent by efferent nerves. Therefore, muscles and glands are the correct answer, highlighting their function as recipients of the signals conveyed by efferent nerves.