1.1 pathway of poison entering human body
poison can enter human body through respiratory tract, digestive tract and skin. 1n industrial production, poison mainly enters human body through respiratory tract and skin, and also enters human body through digestive tract, but it is relatively minor
1.1.1 respiratory tract
is the most important way for industrial poisoning to enter the body. All poisons in the form of gas, vapor, fog, smoke and dust can invade the body through respiratory tract. The human lung is composed of hundreds of millions of alveoli. The walls of alveoli are very thin, and there are abundant capillaries on the walls. Once poison enters the lung, it will soon enter the blood circulation through the walls of alveoli and be transported to the whole body. The most important factor affecting the absorption through respiratory tract is its concentration in the air. The higher the concentration, the faster the absorption
1.1.2 skin
in industrial production, toxicosis caused by skin absorption is also common. After the fat soluble poison is absorbed by the epidermis, it needs to be water-soluble for further diffusion and absorption. Therefore, the water-soluble and fat soluble substances (such as aniline) are easy to be absorbed by the skin
1.1.3 digestive tract
in industrial production, the absorption of poisons through the digestive tract is mostly due to poor personal hygiene habits, and the poisons contaminated by hands enter the digestive tract with eating, drinking or smoking. After the insoluble toxicants entering the respiratory tract are cleared, they can be swallowed through the pharynx and enter the digestive tract
1.2 the process of poison in the body
1.2.1 distribution
after the poison is absorbed, it is distributed to the whole body with blood circulation (part of it is with lymph). When reaching a certain concentration at the point of action, poisoning can occur. The distribution of poisons in different parts of the body is uneven, and the distribution of the same poison in different tissues and organs is more or less. Some poisons are relatively concentrated in a certain tissue or organ, which we call target organ. For example, lead and fluorine are mainly concentrated in bone, while benzene is mainly distributed in bone marrow and lipid
1.2.2 biotransformation
the chemical structure of toxicants is changed by biochemical process after absorption, which is called biotransformation of toxicants. As a result, the toxicity can be reduced (detoxification) or increased (enhancement). Biotransformation of poisons can be attributed to oxidation, reduction, hydrolysis and combination. The metabolites of toxicant formed by transformation are discharged from the body
1.2.3 excretion
toxicants can be excreted in the body after or without transformation. Poison can be excreted through the kidney, respiratory tract and digestive tract, and excretion through the kidney with urine is the most important way. The concentration of poisons in urine is closely related to that in blood. Poisons and their metabolites in urine are often determined to monitor and diagnose the absorption and poisoning of poisons
1.2.4 accumulation
when the total amount of poison entering the body exceeds the total amount of transformation and excretion, the poison in the body will gradually increase, which is called poison accumulation. At this time, most poisons are relatively concentrated in some parts, and poisons can produce toxic effects on these accumulated parts. The accumulation of poison in the body is the basis of chronic poisoning
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