©
  University of Idaho
  All rights reserved.
  Psychology Dept.
  University of Idaho
  Design - P&D

Hello everyone and welcome back. In our past sections we discussed how society has been impacted by alcohol. In this section we are going to talk about how ethanol impacts a variety of different structures. The best way to look about how alcohol impacts body structures is to follow it as it goes through the system.

So let's begin by going to slide two. As we can see here, trace amounts of alcohol are absorbed in the mouth. Ultimately this can cause irritation and if the consumption continues can cause lesions, oral ulcers and can even perforate through the palate, and even oral cancers.

Now, once alcohol goes into the mouth it then goes down the esophagus  As we can see in slide three, all the esophagus is is a tube. It is surrounded by a variety of muscles and blood vessels. It also has a mucosal lining. Now what happens when alcohol goes down this tube? First of all it damages the mucosal lining and can result in ulcers and esophageal cancers. Another aspect that can occur are what we call esophageal varices. Basically the alcohol begins to form irritations on blood vessels (which are enlarged due to increased blood pressure) and these blood vessels rupture and the person drowns in their own blood. This is a bad way to go and is usually fatal when it occurs.

Once ethanol gets through the esophagus it enters the stomach. As we can see in slide four, approximately fifteen to twenty percent of the ethanol is absorbed here. When alcohol does enter the stomach it stimulates the production of hydrochloric acid (HCl) which is used to break down food products in the normal process. However, since there is no food, usually what the HCl will irritate and damage the mucosal lining. The ethanol also changes the electrical properties of the stomach lining. As a consequence of all these things and others, you will get an irritation of the mucosal lining which results in gastritis; and if it continues these can result in ulcers. Finally, as the consumption continues over time, HCl production may actually decrease and you get what we call Achlorhydria. Now, all of these things I have just described here can be modified somewhat if one consumes food. And often when we consume food we have a little wine as our beverage to stimulate the production of HCl. So in some ways alcoholic beverages can be beneficial. However, when one is drinking distilled beverages on an empty stomach you basically can get lots of irritation and lots of damage.

Well, now as alcohol has gone through the stomach it then goes through a valve at the end of the stomach (see slide five) and  is called the pyloric valve. The pyloric valve basically prevents material coming from the small intestine back into the stomach. When a person consumes a large amount of alcohol this valve will actually spasm ,and what it does is prevent the amount of alcohol from going into the small intestine. In essence what it is trying to do is save your life. When it does spasm this causes all sorts of irritation in the stomach area and on the stomach lining. When you get lots and lots of irritation in your stomach what do you do? You puke. In essence, you remove all the alcohol that is sitting in the stomach. Ultimately, this will protect you and prevent you from dying.

Once alcohol does get through this pyloric valve it then moves into the next structure which we see in slide six. This is the small intestine. Here is where the vast majority of ethanol is absorbed. What it does is cross the mucosal lining in the small intestine and then goes into the blood stream which we are going to talk about in a few minutes. Basically, ethanol will damage the mucosal walls of the small intestine. It also damages villi and microvilli.

A picture of the small intestine is shown in slide seven. So let's go there for a minute and then we will come back. As you can see here in slide seven, there is an intestinal passage and the intestinal passage is basically a big tube. But off the wall of this intestinal passage are smaller and smaller tubes. These are what we call the villi and microvilli. The microvilli are connected to blood vessels. What happens when you have some kind of food going down the tube, some of these particles go to the villi, and then the microvilli.  Those nutrients are then picked up by the blood stream and go throughout your body. So, what happens with alcohol?

As we can see in slide eight the same thing happens. When alcohol is in the system, it is going to go down into the villi, then into the microvilli, and finally into the blood vessels and out into the system. You notice here that alcohol is going to go in much quicker than food will. In fact it can prevent food from going into the system which can result in poor nutrition, etc.

So, let's go back to slide six for a second. So what happens when this alcohol in the system? It will decrease the absorption of nutrients and vitamins. It also stimulates the production Triglycerides and Cholesterol.

There are also a variety of other substances that dump into the small intestine.  The first of these comes from the pancreas and this is shown on slide nine. As ethanol comes into the system it will ultimately increase the concentration of pancreatic enzymes.  With damage, this change will then decrease the volume of the enzyme secretion.  Ultimately, the result is pancreatitis. You also get a reduction of insulin production as well.

So let's show how this works on slide ten. We have a pancreatic duct and this is going to go into the small intestine. The pancreatic duct receives pancreatic enzymes from cells (the grey round things at the top). The enzymes then go down into tubes. Those tubes then go down into larger tubes and ultimately dump into the pancreatic duct then on to the small intestine.

So what happens with alcohol in all of this? The first thing alcohol does is inflame the cells and the tubes. The consequence of all this is that fewer amounts of the enzyme material are able to travel down the tubes.  This causes inflammation in the cell linings and the structures making the enzymes.  The results is pancreatitis which can be extremely painful. In addition when damaging the pancreas you are also damaging another structure that makes insulin. This can result in secondary diabetes as well.

Another structure that is impacted and dumps into the small intestine is the Gall Bladder. What alcohol will basically do (as we see in slide twelve) is decrease the amount of Bile that is secreted by the Gall Bladder. In essence it is a very similar process that one sees with the pancreas.

Now as ethanol continues on through the small intestine, if there is enough of it, it will eventually dump into the large intestine.  Here a couple of things happen (shown in slide thirteen). The first thing that will happen is that there is a decrease of water absorption. If there is a decrease of water absorption by the body what do you get? You get diarrhea. In addition, ethanol will also inhibit vitamin absorption by the large intestine. This is really important because you get a lot of your B vitamins and other types of nutrients.

So now we have kind of walked alcohol through the variety of different tracts in relation to the gastrointestinal system. What happens when ethanol is absorbed by the gastrointestinal system into the blood stream then on into other structures?  The first thing that happens (as we can see in slide fourteen) is that it begins to impact blood cells. The first cells it will begin to impact are the red blood cells. What alcohol ultimately does is decrease the production of red blood cells which results in anemia.

Another thing that happens with blood cells (as we can see in slide sixteen) is that it impacts white blood cells. Here again you get decreased production. You also get decreased response time for they immune system. As a result of both of these changes, you get more infections. Further, if you have a decreased immune system and are engaging in high risk behavior there is an increased risk for getting STDs, HIV, and a variety of other diseases.

In addition to the impact of alcohol on the red and white blood cells, alcohol will also impact platelets (slide seventeen). The result of this impact is you get a decreased production of platelets and decreased clotting times. As a consequence you get a lot of bumps and bruises.  These show up as massive black marks on your arms and legs or whatever you hit. You commonly see this in individuals who have been drinking alcohol for a prolonged period. They are basically black and blue all over the place. Any time you have a bump you will get some kind of mark on your arm or other places.

 Now, after alcohol enters the blood stream it then goes to a variety of different structures in the body. So let's talk about these structures and how alcohol impacts them. The first of these is shown in slide eighteen and that is the nervous system.

The nervous system as you remember is made up of a variety of things. The most important thing for us is the neurons which are shown in slide nineteen. The first thing that alcohol does is alters the neuronal membrane or what we call the lipid bilayer of the neuron. This causes a decreased amount of sodium to enter to the axon and results in lower action potential heights. This as we talked about last time alters calcium influx and ultimately decreases the amount of neurotransmitters that is utilized. In addition, ethanol will decrease the transmission speed which the speed of the action potential goes from one end of the axon to the other. Both of these will result in increased tolerance as the cell tries to adapt to the impact of the alcohol in the system. Finally, ethanol will cause demyelization over time. Once the myelin is gone it never comes back.

Ethanol also has some specific impacts on specific types of receptors and some of these are shown in slide twenty. First it inhibits the function of the NMDA receptor which is a subtype of a glutamate receptor. Basically, this decreases responsiveness to glutamate which is a stimulatory neurotransmitter. It also binds on the benzodiazepine unit which is a subunit of GABA receptor. This receptor normally functions to inhibit other neurons. However, when the alcohol is on this receptor it causes this receptor to work even more so shuts down the system. Finally, alcohol also impacts serotonin receptors and this is connected to the reward pathways we often see within the nucleus accumbens.

Now, alcohol does not only impact the neurons it also impacts the entire brain system.  As we see in slide twenty-two it will impact newer evolutionary structures first, then it impacts other older evolutionary structures. For example, it will shut down the frontal cortex or frontal lobes first,  then it shuts down deeper structures (eg., midbrain structures like the Thalamus).  Finally, if you consume too much it will shut down structures such as your Medulla, Pons, etc. When your medulla shuts down you die. In addition, as one consumes alcohol over time alcohol will attack and damage a variety of different lobes including the frontal and temporal lobes which are involved with memory processing and coordination of information. It will also shut down the hippocampus which is basically related to memory. Ultimately, with prolonged consumption you will get decreases in the number of dendrites and axons within the brain.  Consequently, you get an increase in ventricle size (which are the holes in your brain).  You also get decreased blood flow causing a wide variety of problems.

In addition to these problems other problems may also occur due to alcohol consumption. Some of these are shown in slide twenty-three. The first of these are called blackouts. Blackouts are basically amnesia periods that occur while a person is consuming alcohol. That is, you consume alcohol but you do not have any idea of what you did while you were consuming after you sober up.

Another problem that also occurs when one consumes alcohol is sleep changes. And here a person can have restless sleep and/or not have a lot of dream sleep as well. A third major problem that can occur is what we call Wernicke-Korsakoff's Syndrome. Wernicke-Korsakoff's Syndrome as we will talk about in the next slide is characterized by memory loss and confabulation. Finally, there is a wide variety of other psychological problems that can occur including depression and bi-polar disorder, etc.

So what is Wernicke-Korsakoffs Syndrome? Well, as we can see in slide twenty-four, Wernicke-Korsakoff's Syndrome occurs due to a lack of B vitamins. This ultimately occurs because the vitamins are not absorbed from the large intestine due to the alcohol consumption. The ultimate result of Wernicke-Korsakoff's Syndrome and lack of B vitamins is that there is damage to the cortex and peripheral nerve cells. The key symptom of Wernicke-Korsakoff's Syndrome is what we call confabulation. That is, the person has memory loss and so fills it in with other memories to fill in the holes. Usually, your short term memory is the most affected and it has a poor prognosis even after diagnosis. This is one reason why a lot of hospitals will give vitamins to skid row bums who come into the emergency room for a variety of different problems.

Another major system that is impacted by ethanol is the visual system (shown in slide twenty-five). First of all, alcohol does a wide variety of things to the visual system and it begins at very, very low dosage levels. First of all there is a decreased accommodation time. That is, it takes longer for you to accommodate to a wide variety of visual stimuli including light and other things. There is also a decrease in tracking ability. That is, you do not see something moving across time and space. As a person consumes large amounts of alcohol a person may experience double vision. And finally, a person may have a decreased recovery time when bright lights are shown in their eyes. A classic example of this is driving your car at night. When you drive your car and there are oncoming lights coming toward you, after the car passes your system takes a little bit of time to recover. With alcohol this time is reduced (takes longer) even more than it was before and as a result you may wind up in the ditch.

Another system that is impacted by alcohol is the Endocrine System (shown in slide twenty-six). Alcohol impacts a wide variety of different hormones that ultimately have all sorts of effects. A related system is the reproductive system. In males alcohol impacts a wide variety of systems and causes all sorts of effects including Leydig cells which are related to sperm production. It also increases feminine characteristics, causes a decreased sexual drive, causes reproductive failure, and even impotence. In females, alcohol can cause early menopause, premenstrual discomfort, increased menstrual flows because you are decreasing the platelet levels and even infertility.

Alcohol also impacts muscle tissue. The first type of these tissues is the skeletal tissue shown in slide thirty. Generally, ethanol interrupts the internal structure of the muscle tissue. As a consequence you get muscle cramps, pain, weakness and what we call alcoholic myopathy.

Alcohol also impacts the cardiac tissue (shown in slide thirty-one). It will result in an increased heart weight, cause a dilation of the heart chambers, cause scar tissue on the heart itself, and like other types of myopathy, cardiomyopathy, will also occur as well. So, in general, alcohol impacts a wide variety of different systems in the body and has major impacts on each of these as one consumes large amounts over time.