Illness enters by the mouth. This saying describes that most of the diseases enter the body through the mouth. It metaphorically means we should keep a close eye on food safety to avoid food poisoning. Food poisoning is caused by food contamination which refers to the contamination of the food and the raw materials during processing and production by pesticides, wastewater, sewage, and a variety of food additives; plant diseases and pests and livestock diseases; moldiness caused by the toxins produced by fungi or bacteria; and toxic substances and polychlorinated biphenyls, and benzopyrenes in transport or packaging materials. Food contamination can be divided into three categories: biological, chemical, and physical contamination.

Food contamination is hazardous to the human body and has profound effects. If consumed in large amounts, food contaminated by viruses, bacteria, pesticides, and fungi etc., will cause acute poisoning. Long-term consumption will lead to chronic poisoning, such as whole body fatigue and elevation of mercury in urine caused by intake of food containing residues of organic mercury pesticides. Consumption of food containing traces of aflatoxins will cause degeneration of liver cells, hepatic necrosis, fatty infiltration of the liver, and hyperplasia of the bile duct epithelium, or even trigger carcinogenesis. Moreover, chronic poisoning may result in fertility dysfunction, such as infertility, growth retardation, deformity, miscarriage, and stillbirth.

The environment is the main factor in contributing to the evolution and extinction of species. Confronted with the current Earth’s environment that is increasingly severely polluted, humans haven’t yet evolved a relatively defensive mechanism in the mouth and tongue, which serve as the first line of defense for the nutrient absorption of the human body, to block the entrance of toxic food into the body. For humans, this will be unfavorable for the survival of the human line.

The upper surface of the tongue in modern humans is composed of stratified squamous epithelium containing specialized keratin and semi-keratin. The dorsal surface of the tongue is covered by mucosal projections called papillae, the interior portion of which is specialized mucosal connective tissue. There are four types of papillae present on the tongue:

From the above anatomy and physiology of the tongue, we can see that the tongue of modern humans merely has the basic function of distinguishing the tastes of the food. It is incapable of identifying toxic food. The tongue thus cannot stop contaminated toxic food from going into the body, so food poisoning is totally unavoidable to modern humans.

The tongue of the New Human Line has the new physiological function of toxic reflex. The structure of the lingual papillae and the connection of the nerves differ from that of modern humans. The filiform papillae on the tongue of the New Human Line evolved from the original cone shape into the dome shape, from the smallest in size to the largest in size. The largest amount and most distribution of the filiform papillae evolved into an oval shape with it located at the center of the tongue. The fungiform papillae, dispersed among the filiform papillae as small red spots, evolved from red in color into semitranslucent white. The physiological function of the papillae also evolved from detection for the tastes into detection for the toxins, capable of identifying biological, chemical and physical contamination (See Picture 1).

The nerve transmission mode of the filiform papillae on the tongue of the New Human Line evolved from the original electrochemical collaborative transmission into resonance transmission. This transmission mode has no lapse in transmitting messages and thus enables the New Human Line to instantly detect toxic substances as soon as the toxic food enters the mouth and promptly block the entrance of the toxic substances into the body. Moreover, for the trace amount of toxins that have gone into the mouth, the toxic reaction will be relayed to the vomiting center, the area postrema, which in turns initiates nerve impulses that propagate along the vagus nerves, sympathetic nerves, phrenic nerves, and spinal nerves to the stomach, intestines, diaphragm, and the muscles of the abdominal wall to instantly vomit the trace amount of toxins.

The environment of the Earth is highly polluted, either by biological, chemical or physical contamination. They exist everywhere, involve everything, and appear to be even harder to prevent. The emergence of the toxic reflex of the tongue not only allows the New Human Line to accommodate to the highly contaminated environment on Earth but also makes the New Human Line no longer be a living organism by whose mouth illness enters.

References:

1. Lingual papillae (2017). Retrieved from https://en.wikipedia.org/wiki/Lingual_papillae
2. Tongue (2017). Retrieved from https://en.wikipedia.org/wiki/Tongue