Friends who like to eat chili must feel the same as the old saying "chili is hot at both ends", because when eating chili, the mouth will feel spicy first, and then when it is convenient to go to the toilet, the "chrysanthemum" will feel hot again. It feels hot and painful, but when you eat spicy food such as green onion, ginger, garlic, etc., you won’t have the "spicy" feeling like chili. What's the matter?
The reason why we feel hot when we eat hot peppers is mainly due to two objective reasons. Firstly, there are two objective reasons for the hot pepper. Then there are taste buds on our tongues. Capsaicin is an alkaloid. When people eat hot pepper, this alkaloid can bind to vanilla receptor subtype 1 in the sensory neurons of the taste buds on the tongue. This will give the human nerves a spicy sensation, similar to A kind of burning sensation. In fact, capsaicin will not only act on the nerves on the human tongue, it will also cause a burning sensation on the skin. When you break the pepper with your hand, if your hand is wet, then the pepper When the element acts on the superficial nerves under the skin, it will also cause a burning sensation.
is also because of this reason, when we eat chili, there are fewer nerves in the esophagus and digestive tract, so you can hardly feel the spicy or burning sensation, but sometimes there will be some slight stomach It feels like, when capsaicin passes through the human digestive system, most of it still exists, and the nerve endings inside and outside of the human anus. The door is richer. This is also the soft membrane tissue. Capsaicin is easier to penetrate, so the "chrysanthemum" is also I can feel a burning sensation.
These reasons are actually relatively easy to understand. What is really not easy to understand is the signal transduction mechanism of human nerves. We know all the sensations of the human body, including hot or cold, hard or soft, squeezing or pain, pleasant touch and even certain aspects of pleasure, etc.They are all distinguished by the somatosensory system, which transmits these stimulus signals to the brain, and then the brain responds. Among them, smell and taste are first caused by chemical reactions, and then are physically transmitted by biological electrical signals, while vision, hearing, and touch are mainly signal transmission stimulated by physical phenomena.
From the neural level, the transmission of stimulus signals can be simply understood as "receiving stimuli-transmitting signals"-the brain first receives and responds The stimulation activates the ion channel receptors on the sensory nerve membrane to generate electrical impulses. The pulse signal is transmitted to the sensory area of the brain through the dorsal root ganglia. In this process, a structure called sensor is required to play a key role. It is like a lock or a door, which is usually closed, but under certain circumstances, it will be activated by bioelectric pulses. It's like a lock or door is opened.
When we taste different tastes, different "locks" or "doors" will be opened. For example, when we taste the sour taste, there will be a lock or door specifically responsible for the sour taste When the lock or door responsible for other tastes is opened, there is no response. When the bitter taste is tasted, only the lock or door responsible for the bitter taste is opened. When the taste is sweet, salty, spicy, mint, etc. Similarly, every taste has the nerve signal transmission that is specifically responsible for this taste, but no matter which taste it is, the sensor responsible for this taste will only be encountered when it encounters a molecule whose shape and chemical composition meet its requirements. Turn on, so this is an electrical impulse signal generated by a chemical reaction. After this signal is generated, it transmits a signal to the brain through a neural pathway , and then we can produce sour, bitter, sweet and other taste information.
among them,The spiciness is special because scientists have discovered that it is not a taste, but a feeling of temperature, which is manifested as a hot burning sensation, which is more obvious when it is discharged after eating hot peppers. It does not feel as hot as the mouth, but usually only feels the hot burning sensation. The scientist who discovered this physiological mechanism won the Nobel Prize in Physiology or Medicine this year (2021). The two scientists named David Julius and Adem Pataptian, both Americans, independently discovered the temperature and tactile receptors in the human nerves, and discovered that the spiciness is emitted by this receptor Signal.
The Nobel Prize jury claimed that the two pioneers discovered how cold, heat and mechanical forces activate neural signals, allowing us to perceive and adapt to the world around us. Now the two people's research results are widely used in the medical field, and also help to turn virtual reality (VR) into a more realistic tactile experience.
References:
"Beijing Daily" October 5 article "Two scientists share the Nobel Prize in Physiology or Medicine, They Solve the Mystery of Human Perception"
.
