Identify receptors as cells or organs that detect stimuli and monitor internal or external changes.

Receptors are specialized cells or organs that play a crucial role in the process of homeostasis by detecting stimuli from both internal and external environments. They monitor changes, such as variations in temperature, light, or chemical levels, and send this information to coordination centres, like the brain or spinal cord. This detection is essential for the body to respond appropriately and maintain stable internal conditions, ensuring that physiological processes function optimally. Understanding the role of receptors is fundamental in grasping how organisms regulate their internal environments.