Toxins, Toxicity and Toxicology |

Earth is a planet which has all the necessary conditions for life and life activities; now as living organisms, we humans are not the only inhabitants of this place, we have other higher animals like the snakes, monkeys, crocodiles, flies, fishes, birds here, as well as smaller organisms which can only be seen with the aid of special instruments. The earth as we know it also contains substances which are harmful to life, these substances can be classified as poisonous. These poisonous substances exist naturally, some synthesized due to human activities and others produced by living organisms themselves. The poisonous substances produced by living organism are called toxins

What are Toxins?

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Toxins are poisons of organic sources, meaning they are produced or found in living organisms including plants and animals.Toxins are poisonous substances produced within an organism and its cells. They are harmful and often times regarded as biologically produced poisons. They are small molecules, polypeptides or proteins capable of disrupting normal physiological and metabolic functions of the cells. This interference leads to development and expression diseases and possibly death in most cases.

There is a word also common known as toxicants and this is the comparison between the two words. Toxins are endogenous substances produced within an organism's body while toxicants are toxic or poisonous substances that can either be endogenous, synthesized or natural component of the environment. So all toxins can be regarded as toxicants but not all toxicants are toxins. Example of toxins are the venomous compounds produced by animals in killing or paralyzing preys, these substances are toxic hence can also be referred to as toxicant. Toxicants that are not toxins are the common Carbon Monoxide from generator and combustion vehicles, Lead when breath in, industrial fumes etc.

Mode of action of Toxins

As explained above, toxins disrupt the normal physiological function or activities of a cell, this is how toxins actually do this which lead to diseases, death of cells and ultimately the whole organism dying. The cells of multicellular and unicellular organism are always in action to keep the internal environment stable; this is called homeostasis. It has a cell membrane which is semipermeable giving it selective absorption of substances. Not all substances can enter into the cell. The cell membrane also have receptors which hormones and drugs bind with to cause reactions such as growth, secretions, feeling etc. rotenone and cyaninde. These respiratory blockers act by interfering with the electron transport chain of mitochondria of the respiratory system. The electron transport chain is a series of biochemical reaction in mitochondria of cells to produce energy. When this is interfered by the repiratory blockers, the respiratory system wont be able to deliver oxygen needed for cellular respiration of the organism. This often result in death.

• Central Nervous system seizure agents affect the central nervous system. I would recommend yo u read my last post
  on the electrical system of the body. The central nervous system of the body include the brain and spinal cord and are the chief coordinating organs of the body responsible for motor movement, sensing external and internal stimulus as well as higher activities such as learning and memory. The CNS seizure agents prevent cellular signalling of the brain and spinal cord. This causes the brain to loose control of its own body. Major example of such agents is chlorides used in pesticides and insecticides.

• Uncoupler of oxidative phosphorilation are substances that uncouple oxidative phosporilation thereby preventing production of ATPs.

• Other modes of action include Acetylcholinesterase inhibitor which inhibit breakdown of neurotransmitter Acetylcholine and irritants which cause inflammation at site of contact.

Toxins, Venom and Poisons

The Box Jelly is one of the most venomous animals in the world causing more than 5,600 deaths since 1954. Its venom attack the skin, heart and nervous tissues.

Venom are forms of toxins secreted with the intention of causing harm to another organism. In 1990, venomous animals killed a total of 76, 000 people. There is however a difference between poisonous animals and venomous animals.; both poisonous and venomous animals produce poisons (toxins) or to be more specific, venom, the difference between these two animals are mode of delivery. Venomous animals inject the toxins into their victims while poisonous animals don't have any delivery method. Not all snakes are venomous, not all snakes are poisonous too. Example of animals that produce venom are spiders which uses fangs to deliver the venoms, scorpions, shark, sting rays, dragonet, salamandrid salamander etc.

Toxins and Micro-organism

Not all micro-organisms are dangerous, some are essential in fermentation of our food as well as nor physiological well being of our body. However, there lies a certain percentage of micro-organism population that their activities is harmful to human and animal's health. These micro-organisms are said to be toxic to life and human health. Their activities might release toxins into the host body, this toxins are known as microbial biotoxins. Other micro-organism do not produce toxins but deprive the body of the nutrients needed for it normal physiological functions.

Biotoxins

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Biotoxins is more specific than toxins. It is a term used to explicitly confirm the biological origin of the poisonous substance. There are four major classes of biotoxins:

• Fungal Biotoxins
• Microbial Biotoxins
• Plant Biotoxins
• Animal Biotoxins

Fungi are eukaryotic organisms which do not belong to the animal or plant kingdom. They are neither plant or animals, they are fungi. Example of fungi are mushroom. Fungi biotoxins are toxins produced by fungi. Microbial biotoxins are toxins of bacterial origin, they act by damaging host tissue as well as disabling the immune system. However, biotoxin has been carefully controlled and tend to be usefull in medicine especially in combating cancer,
Plant biotoxins are of plant origin while animal biotoxins are of animal origin.

The primary function or reason for biotoxin secretion is for predation as seen in spiders, scorpions, jellyfishes, wasp etc or for defense as seen in bees, termites, wasp, ants etc. Most toxins affect only specific cells and system rather than the whole body tissue; examples are Neurotoxins which affect the nervous system. Examples of other biotoxins include cyanotoxins, dinotoxins, necrotoxins etc.

Toxicity

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Toxicity is the degree at which a chemical substance can have a devastating effect on an organism. Toxicity is not limited to toxins or biotoxins, it studies degree of harmfulness of all toxicants. It can be studied on an organism or secluded to a particular cell such as a liver cell; in this case, toxicity is more specific and referred to as hepatotoxicity. One of the major terms used in toxicity is intoxication.

Intoxication is defined as an abnormal state that an individual, organism or cell is said to be poisoned. When a substance which is not normally harmful such as water reaches a degree of toxicity, it is referred to as toxification. Human get involved in a lot of activities that leads to them getting intoxified. Examples of intoxification or intoxication include:

• Alcohol Intoxication (Excess Alcohol Intake)
• Water Intoxication
• Drug Over use
• Cocaine Intoxication
• Carbon Monoxide Intoxication/ Poisoning

Toxicity studies the amount of dose of a substances needed to cause a detectable toxic effect. A snake venom when injected into a victim might not show any effect, this might be because the amount or dosage of the venom is very
little to cause an effect. Different substances have different toxicity level, some substances are more toxic than the other while some substances are only toxic in presence of other substances. Toxicity depends on age, sex, weight and species of organism.

Toxicology

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Toxicology is essential in Medicine, research as well as forensic science. It is a branch of science dealing with environmental pollution, biotoxins, drugs and activities of man which is toxic to lifeThis is a branch of science that deals with toxicants. It brings together the knowledge of biology, microbiology, chemistry, biochemistry, pharmacology and medicine. It studies the adverse effect of chemical substances of different origin on a living organism. It is an essential part of drug production. There are other sub-discipline of toxicology which include:

• Medical Toxicology
• Chemical Toxicology
• Computational Toxicology

Mechanism in Human against Toxins

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The major organ of the human body concerned with proper toxin management and excretion are the liver and the kidney. Other organs are the skin and lungs
Most animals have blood colored red due to the presence of hemoglobin, but there are some animals which differ in the color of the blood. Example is the green-blooded skink and as the name implies has green blood. The animal has a high level of biliverdin which is a green pigment molecule derived from the break-down of hemoglobin. Human blood also contain this substances but not in the quantity of this green-blooded skink. Biliverdin is a toxin as toxic to human health in the quantity present in the green-blooded skink.

To prevent toxins from accumulating in the body, it has developed processes and organs against accumulation of toxic substances. Organs involved in detoxifying in human are the kidney, lungs, skin, digestive tract and liver. Gaseous substances such as Carbon Monoxide exit the body from the lung. Urea is prevented from accumulating in the body by the action of the kidney. The liver deactivates toxic substances and convert them to less toxic compounds so as to be excreted by the kidney, skin, lungs and digestive tracts.

The most important organs involved in toxic management are the liver and kidneys. You can read my previous post on the liver, it is an bilobed organ of the body involved in a lot of life activities. Even when humans live a clean and hygienic life, the problem of toxins will evident in absence of the kidney and liver. This is because during metabolic activities, the body is constantly producing toxins.

Detoxification

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Detoxification is often practiced as a cosmetic measure. Removal of toxins from the body improves appearance of the skin muscles and the overall well being of an individual
This is the removal of toxic substance fro a living organism. In humans, this process is carried out majorly by the liver. There are different reasons for detoxification ranging from cosmetic reasons, bringing the body back to state of homeostasis to curing diseases and preventing death. The following are the different types of detoxification:

• Alcohol Detoxification
• Drug Detoxification
• Metabolic Detoxification
• Alternative medicine

The aim of the types of detoxification is different depending on the desired result.

Further Reading:

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• Wikipedia: Toxicants
• Wikipedia: Toxin
• Mode of Toxic Action
• Wikipedia: Toxicity
• Botulinum
• Merriam-Webster: Intoxication
• Detoxification

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