Estrogen receptors are special proteins found in various tissues throughout the body that bind to the hormone estrogen. When estrogen attaches to these receptors, it triggers a series of biological responses that influence many functions, including growth, reproduction, and mood regulation. There are two main types of estrogen receptors: ERα and ERβ, each playing different roles in the body. These receptors are crucial for the development of female characteristics and the menstrual cycle. They also play a role in bone health and cardiovascular function. Understanding how estrogen receptors work helps researchers develop treatments for conditions like breast cancer and osteoporosis.