You’ve heard all of the statistics and the horror stories. You have been told of the effects of alcohol use and abuse for years. Since coming to college, you may have observed or experienced these effects first-hand. But, do you know the biological effects of drinking?

Alcohol is not digested like other foods. Alcohol avoids the normal digestive process of being converted and transported to cells and tissues and goes directly to the blood stream. Approximately 20% of the alcohol is absorbed directly into the blood through the stomach walls and 80% is absorbed into the bloodstream through the small intestine.

Alcohol dilutes itself with the water volume of the body in order to travel through the system. Vital organs that contain a lot of water and an ample blood supply (like the brain) are very vulnerable to the effects of alcohol. The dilution that occurs in the body does somewhat cut the effect of the alcohol. The one major biological difference between men and women comes into play here – muscle tissue contains more water than fat tissue. Men tend to have more muscle and less fat on average than women. This means that if a man and a woman of equal weight consume the same number of drinks, the woman will be more adversely affected.

The brain, heart, liver, lungs, pancreas, lungs, kidneys, and every other organ and tissue system are infiltrated by alcohol within minutes after it passes into the blood stream. The drink’s strength will have a significant effect on absorption rates. Higher concentrations of alcohol result in more rapid absorption. Pure alcohol is generally absorbed faster than diluted alcohols, which are, absorbed faster than beer or wine.

Alcohol taken in concentrated amounts irritates the stomach lining, causing it to produce a sticky mucous which delays absorption. The pylorus valve which connects the stomach and small intestine can go into spasms with the introduction of concentrated alcohol. This traps the alcohol in the stomach instead of passing it on to the small intestine where it would be more rapidly absorbed into the blood stream. The drinker who downs drinks in quick procession (like at pre-parties) in an effort to get a quick buzz may actually experience a delayed effect. Finally, warm alcohol is absorbed more rapidly by the body than cold alcohol. The actual blood alcohol content (BAC) of a drinker is influenced by the amount of alcohol consumed, body size and proportion of body fat, the amount of food in the stomach, and what is mixed with the alcohol. BAC rises more rapidly in those who drink on an empty stomach. Water and fruit juices slow the absorption process, while carbon dioxide speeds it up. The carbon dioxide in champagne and carbonated mixers rushes through the stomach and intestinal walls into the blood stream. This creates a rapid rise in BAC. If you drink faster than your body can eliminate, alcohol accumulates in the blood stream and the BAC rises.

Alcohol elimination from a healthy adult body occurs at an average rate of approximately ½ to ¾ ounce per hour. This is equivalent to 1 ounce of 100-proof whiskey, one large beer, or about 3 to 4 ounces of wine. A .30 BAC is the minimum level at which death can occur. At .40 the drinker may lapse into a coma. At .50 BAC, respiratory functions and heartbeat slow drastically. At .60 most drinkers are dead.

The liver is the body’s largest glandular organ. Its functions are associated with numerous body chemistry processes and metabolism. It produces the bile that helps digest fatty foods. It manufactures heparin, an anticoagulant. It stores and releases sugar. The liver also produces antibodies that help ward off disease and it cleanses the body of poisons. With small amounts of alcohol, this cleansing can happen effectively. When the amount of alcohol is high, imbalances are created. This can lead to hypoglycemia (low blood sugar), hyperuricemia (as in arthritis or gout), fatty liver (which may lead to hepatitis or cirrhosis), and hyperlipemia (build-up of fats sent to the bloodstream which can lead to heart problems).

The central nervous system (CNS) includes the brain, the spinal cord, and the nerves originating from it. Sensory impulses are transmitted to the CNS and motor impulses pass from it. When alcohol acts on the CNS, intoxication occurs. This affects emotional and sensory function, judgment, and memory and learning ability. The senses of smell and taste are dulled. The ability to withstand pain increases as the BAC rises.

Different parts of the brain seem to be affected by alcohol at different rates. This can create alternate periods of restlessness and stupor. The long-term effects of alcohol on the central nervous system include tolerance, dependency, and irreversible damage. Changes in tolerance and dependency demonstrate that physical changes do occur in the brain. With each episode of drinking, central nervous system functions deteriorate in a predictable sequence. It starts with intellectual functioning. This is followed by disturbances in sensory and motor control. Affected last are the automatic biological functions, such as breathing and the beating of your heart.

The brain is the organ that is most affected by alcohol. Three of the most noticeable effects of alcohol injury to the brain include: memory loss, confusion, and augmentation. Augmentation results in hyper-alertness to normal situations, perceiving light as brighter or sounds as louder than usual, or the drinker’s becoming extremely sad or angry for no apparent reason. The drinker’s rapid mood swings and instability can be brought under control by drinking cessation.

Blackouts or memory loss are a physical effect of alcohol on the brain. They occur because alcohol cuts off the supply of oxygen to the brain. Lack of oxygen to the brain can kill thousands of brain cells every time a person becomes intoxicated. One effect of drinking alcohol is known as "blood-sludging.” This is where the red blood cells clump together causing the small blood vessels to plug up. This starves the tissues of oxygen and cause cell death. This cell death is extremely serious and often unrecognized. This increased pressure in the brain can cause capillaries to break, create red eyes in the morning, and contribute to red, blotchy skin seen on the faces of many heavy drinkers. Blood vessels can break in the stomach and esophagus. This can lead to a hemorrhage, even death.

Other effects of alcohol on the blood include: anemia; sedation of the bone marrow (which reduces the red and white blood count and weakens the bone structure); lowered resistance to infection; and a decrease in the ability to fight off infections.

The stomach, the small and large intestines, and the pancreas are each affected by alcohol. Alcohol increases acid in the stomach. Increased acid production can result in gastritis or ulcers. The pancreas produces insulin which is necessary to regulate the amount of sugar in the blood. Drinking causes a steep rise in blood sugar. The pancreas responds by producing insulin, which causes a fast drop in blood sugar and the symptoms of low blood sugar or hypoglycemia. 70-90% of alcoholics suffer from hypoglycemia (chronic low blood sugar) as a long term effect of drinking. Symptoms of hypoglycemia can include dizziness, headaches, lack of concentration, depression, anxiety, light-headedness, tremors, cold sweats, heart palpitations, loss of coordination, and upset stomach. The drinker’s overworked pancreas may stop producing insulin altogether and diabetes can result. A person with a family history of diabetes may be more vulnerable to problems with alcohol.

Alcohol reduces blood flow to the muscles (including the heart) causing muscle weakness and deterioration. One outcome is cardiomyopathy (sluggish heart) which is common in alcoholics. Another outcome, arrhythmia (irregular heartbeat) is commonly treated in emergency rooms after a drinking binge. Muscle aches are also a common symptom of excessive-drinking.

The endocrine system controls the body’s hormones. This system includes the pineal, pituitary, thyroid, and adrenal glands, and the ovaries or testes. Alcohol sedates these glands, resulting in under-production of hormones. This can produce an increased susceptibility to allergies.

Alcohol can effect sexual functioning in various ways. In low doses, it lowers inhibitions and may make a person feel desirable and alluring. In higher doses, it can decrease sexual functioning. In men, this may mean a decrease in the frequency of erections, decreasing the maintenance of erections, decreasing penile size during erection, and increasing time between erections. For women, this may mean an interference with the normal processes of sexual stimulation, and blocking orgasmic response. With chronic and prolonged use of alcohol men may experience shrinkage of sex glands and an increase of the hormone estrogen. This can produce secondary sexual characteristics, such as enlarged breasts and a decrease in body hair. Prolonged use of alcohol can cause infertility in both men and women.

There are a few additional concerns for females that drink. Female drinkers reach higher BAC’s faster because of less water in the body, more fat, and because of differences in digestive enzymes. The menstrual cycle affects alcohol metabolism in women. Women have been shown to develop their highest BAC’s immediately before menstruating and their lowest on the first day of menstruation. This is related to shifts in hormone levels. There is evidence that premenstrual syndrome (PMS) can trigger excessive drinking by some women.

While most of the physical effects of alcohol use are temporary, they can result in death. Alcohol depresses nerves that control involuntary actions such as breathing and the gag reflex (which prevents choking). A fatal dose of alcohol will eventually stop these functions.

It is common for someone who drank excessively to vomit since alcohol is irritating to the stomach lining. There is then the added danger of choking on vomit. It could very well cause death by asphyxiation in a person who is not conscious because they are intoxicated.

A person’s BAC can continue to rise even while they are passed out. Even if the person has stopped drinking for the night, alcohol in the stomach and intestines continues to enter the bloodstream and circulate throughout the body. Some signs of alcohol poisoning include:

• Mental confusion, stupor, coma, or person cannot be roused.
• Vomiting.
• Seizures.
• Slow breathing (fewer than eight breaths per minute).
• Irregular breathing (10 seconds or more between breaths).
• Hypothermia (low body temperature), bluish skin color, paleness.

If someone with alcohol poisoning is not immediately treated, the following can occur:

• Victim chokes on his or her own vomit.
• Breathing slows, becomes irregular, or stops.
• Heart beats irregularly or stops.
• Hypothermia (low body temperature).
• Hypoglycemia (too little blood sugar) leads to seizures.
• Untreated severe dehydration from vomiting can cause seizures, permanent brain damage, or death.

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