The Digestive System

The digestive system is responsible for collecting the nutrients essential for our survival. From ingestion, to digestion, to absorption and elimination, the digestive system integrates many organs. In the alimentary tract, we have the stomach, small intestines and colon; as accessory organs, we have the liver pancreas and gall bladder. This section focuses on methamphetamine’s adverse effects on the digestive system.

The Alimentary Canal (Gastrointestinal Tract):

Overview of the Digestive System

When foods or drinks are ingested, they enter through the mouth and once swallowed, travel through the esophagus into the stomach. Digestion begins in the mouth with salivary amylase, continues with pepsin in the stomach, and ends with lipases, proteases, nucleases and pancreatic amylase in the intestines. In the small intestines, previously digested and broken-down monomers diffuse into capillaries through microvilli while fats are absorbed into lacteals. The colon absorbs water as needed, and finally undigested wastes and unabsorbed nutrients are eliminated from the body through the anus.

When methamphetamine is ingested, it effects the entire digestive system. This begins in the mouth. Meth mouth is a term used to describe a meth user’s the rotten and decayed teeth. There are multiple reasons why methamphetamine causes meth mouth. One reason is that methamphetamine is such an intense psycho-stimulant (a drug that stimulates mental and physical activity) it causes users to neglect their dental hygiene. As referenced in the nervous system section, methamphetamine usage lowers cerebral function. Therefore, it correlates with an increase in impulsive and less logical behaviors because of decreased frontal cortex activity. Because of this, methamphetamine users feed all of their desires and addictions, and frequently binge eat sugary foods.

Meth Mouth Decay

In addition to this, chemicals used to synthesize methamphetamine such as anhydrous ammonia remain in the crystal meth after production. When ingested or smoked, they and can cause corrosion of tooth enamel (PBS 2008). The drug itself also causes major changes in the body by stimulating the sympathetic nervous system. Prolonged usage of methamphetamines and large doses of the drug can keep the sympathetic nervous system running too long. When the body is constantly strained, decreased blood flow to the mouth can cause gums to deteriorate and cause teeth to fall out.

Montana Meth Project Advertisement Against Meth

When the sympathetic nervous system is activated, the digestive system is mostly shut down and energy is diverted to power a fight or flight response (University of Georgia, 2010). This causes a severely decreased metabolism and a lack of absorbed nutrients due to decreased digestive functions. This in turn causes other negative health issues such as extreme loss in weight and malnutrition. Depending on what few foods are consumed, methamphetamine users commonly experience constipation or diarrhea. Decreased thirst can cause dry mouth and further the severity of meth mouth (MileHighMethProject 2012).

Emaciated Meth Users

The Accessory Organs of the Digestive System:

The Liver:

From storing glycogen to hormone production, the liver plays a major role in the human body. The liver is necessary for survival; there is currently no way to compensate for the absence of liver function long term (Medicine Plus). Thus, this section will explore methamphetamine’s adverse effects on the liver.

In Denver, home-cooked meth is only 10 to 20% crystalized methamphetamine, and the majority of the substance is saturated with toxins and byproducts of the dangerous and hazardous cooking process. If the drug is ingested, the substance will be absorbed in the gastrointestinal tract, mainly through the small intestines. As we have learned in class, these small molecules can passively diffuse through microvilli in the small intestines.

Microvilli in the Small Intestines

Once they are through the microvilli, they can passively diffuse through the simple squamal epithelial cells of capillaries and pass through the bloodstream. Their first stop in the blood stream, however, is the liver, through the Hepatic Portal veins. Here in the liver, the methamphetamine molecules as well as the toxins from the cooking process are absorbed into individual liver cells where the endoplasmic reticulum of each cell processes these chemicals.

The Liver and Hepatocytes

As shown in the diagram above, the hepatocytes (liver cells) are the functional units of the liver and process the detoxification of drugs and toxins. The liver is able to breakdown methamphetamines into smaller and simpler chemicals so that they can be filtered out by the kidneys and excreted. With each cycle of circulation through the bloodstream, more and more of the drug is broken down, filtered out and excreted.

Crystal meth carries many extremely toxic chemicals from the cooking process including: chloroform, ether, hydrochloric acid, lithium, and many more.
These chemicals are extremely harmful to the liver, and cause immense stress on the body because nutrients, vitamins, minerals and energy are expended during the process of detoxifying these toxins.

The Pancreas:

Although the liver and pancreas are classified as “accessory organs” of the digestive system, they are critical for the health and wellbeing of a person. The pancreas, although small in size when compared to many other organs, plays a vital role in the digestive system as well as the endocrine system. This section focuses on methamphetamine’s adverse effects on the pancreas.

The Pancreas

The pancreas secretes numerous fluids that aid the digestion of food in the intestines including the following: bicarbonate to neutralize the pH of chyme (digested food from the stomach), proteases to breakdown proteins into amino acids, lipases to breakdown complex fats into simpler fats and glycerol and fatty acids, pancreatic amylase to break down sugars into monosaccharides, and nucleases to break down DNA and RNA into nucleotides.
As discussed in Dr. Ferguson’s General Biology I Lecture, organs are composed of two or more tissues, and tissues are composed of two or more cells. But what happens when drugs such as methamphetamine disrupt and damage the tissues of the pancreas? According to a study by Ito in 1997, the chronic stimulus of methamphetamine in rats causes significant changes in pancreatic tissues and may cause deterioration of vessels supplying the pancreas with blood; therefore introducing a risk of hypoxia, or lack of oxygen. This study was conducted in 1997 at Saga Medical School in Japan. The abstract can be found at this link: A Histopathological Study of Pancreatic Legions After Chronic Administration of Methamphetamine to Rats.
If the pancreas ceases to function properly, digestion can slow down and become less efficient, thus causing a vicious cycle of malnutrition and weight loss for methamphetamine users.

Comments
  1. brooksaurora says:

    I like how you connected your topic to each biological system and provided well thought-out examples as well as photos and diagrams to go along with what you were explaining. You connected the complex topics we learned in class to an interesting topic.
    It would be interesting to hear more about different studies that have been done with this drug (maybe some more recent ones) and learn about what more modern research has found and see more examples of the detrimental effects of this drug.

    -Alea S.

  2. neta mills says:

    could the use of meth cause you to get hyperglucemia high blood sugar? and could quitting allow the pancreas to work again?

  3. DR noone says:

    well now, everything he said is true. but he left out one thing…. the long term effect of meth makes flesh eating zombies only thing is with the lack of teeth it just makes for extreame guming unless they have obama care and are provided with dentures then things can get hairy and punji sticks shoud be set in a circle, square or what ever other closed perimeter of your choosing. meth should be placed inside so that the user(zombie) is impelled.it is well known that a starving tweeker will choose meth even when starving this may be your only recourse to ward off tweekers/zombies.

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