The document discusses the senses and nervous system. It explains that sensory organs like the eyes and ears detect information from the environment and send it to the brain or spinal cord for interpretation. The brain or spinal cord then sends signals to motor nerves which transmit impulses to muscles, allowing for both voluntary and involuntary movement in response to sensory information. It provides details on how each sense organ like the eye, ear, and skin works to detect stimuli and relay that information through nerves to be processed.