Vol. 7, Issue 2, Part D (2025)

Receptors in the body constantly monitor changes both inside and outside the body. From the external environment, they detect stimuli such as temperature, light, and sound, while within the internal environment, they sense variations in pressure, pH levels, carbon dioxide concentration, and electrolyte balance. All this gathered information is known as sensory input. The sensory input is then converted into electrical signals called nerve impulses, which are transmitted to the brain. In the brain, these signals are processed and combined to create sensations, produce thoughts, or store memories. The process of interpreting and organizing this information to make decisions is called integration. Based on the sensory input and the integration process, the nervous system generates a response by sending signals through motor neurons to effectors such as muscles and glands. Muscles respond by contracting, leading to movement, while glands respond by secreting hormones or other substances. These actions are collectively known as motor output or motor function. Effectors are so named because they bring about an effect in response to the nervous system’s directions, allowing the body to react to changes and maintain proper function and balance.