Human senses are divided into five categories, namely, touch, smell, taste, hearing and vision. However, with the in-depth study of biology and human brain science, researchers have discovered several other senses of human beings. In addition to the "five senses", there are actually many sensory receptors everywhere in the human body, which play a very important role, such as keeping the body balanced and sending out hunger signals.

Sense of balance. When you stand or walk, you won't fall down, thanks to a sense of balance. The sense of balance is controlled by lymph in the inner ear, and people can walk safely with vision. If it keeps turning, the system will not work normally, leading to dizziness and loss of balance.

Proprioception. When we close our eyes and raise our hands, we know where our hands are without looking. This is the proprioception at work, which allows us to know where the body parts are without looking. It doesn't sound very useful, but without this feeling, people need to keep looking down at their feet before they can walk. When checking drunk driving, the police will also test proprioception.

Thermal sensation. Sitting by the campfire, people can feel the heat. Take out a piece of ice from the refrigerator and people can feel the cold. Temperature sensors on the skin can sense temperature changes. Previously, the ability to detect hot and cold was classified under the sense of touch. However, people don't need to touch something to feel its heat (for example, sitting by a campfire, we can feel the heat without touching it), so the heat feeling is a separate feeling. The thermal system in the brain can detect and control the core body temperature.

Pain. This feeling can sense pain. Paul fuchs, deputy director of the Center for Sensory Biology at Johns Hopkins University, said that nociceptive feelings and thermal feelings are often mixed together because, to some extent, they both use the same skin neurons. Injury sensors are not only distributed in skin, but also in bones, joints and internal organs.

Inner feelings. This is the general term for controlling the internal sensation of organs in the body. Fuchs said that there are various receptors in the human body that trigger the subconscious and make conditioned reflex, which is of great significance to health. Most unconscious behaviors of human body are controlled and managed by such receptors, such as causing cough, controlling respiratory rate, giving reminders when hungry or thirsty, etc.