Which internal conditions can interoceptors detect?

Interoceptors are specialized sensory receptors that sample the internal environment of the body. They play a vital role in maintaining homeostasis by monitoring various physiological states.1

Specifically, interoceptors detect the following internal conditions:

• Digestive and Excretory States: They report the status of the bladder and the alimentary canal, mediating experiences such as hunger and thirst.12
• Circulatory and Blood Chemistry: They monitor blood pressure, heart rate, and the osmotic pressure of the blood plasma. Additionally, receptors sensitive to carbon dioxide levels in the blood are present within the circulatory system.12
• Metabolic and Thermal Regulation: Certain cells, particularly in the hypothalamus, act as receptors sensitive to changes in blood chemistry—such as water and digestion products—as well as fluctuations in temperature within the brain itself. Some chemoreceptors also detect glucose levels or the acid-base balance in the blood.21