Your entire digestive system.

Your stomach is located at the end of your esophagus and is the terminus for swallowed food and drink. The stomach receives chewed food and continues to mechanically and chemically break it down into smaller pieces, creating more surface area for your small intestine to absorb nutrients.

Your stomach is an acidic environment with a low pH of between 1 and 3. Parietal cells in the wall of the stomach secrete hydrochloric acid (HCl). If your esophageal sphincter; basically the lid to your stomach; isn’t closed properly, HCl will creep into your esophagus resulting in heartburn. HCl has a few different jobs. One, is to kill bacteria or other potentially dangerous pathogens you may have unknowingly ingested with your food. Another is to convert pepsinogen into pepsin. Pepsinogen is released from chief cells in your stomach wall. HCl, chemically changes pepsinogen into pepsin and is essential because pepsin doesn’t function in an environment with a pH greater than 5. Pepsin begins protein digestion by breaking it down into peptide chains. Peptide chains are made up of amino acids. Your small intestine absorbs amino acids into your circulatory system for distribution to the rest of your body. It is important to note there is a layer of mucus protecting your stomach from being chemically broken down by pepsin and HCl.

Parietal cells of stomach wall

Parietal cells in your stomach wall also secrete intrinsic factor; a substance whose only job – as far as scientists know – is to facilitate the absorption of  vitamin B-12.  Intrinsic factor cannot do its job in the acidic environment of your stomach; it works best in a pH of 7 – close to water – but is used later in your ileum to absorb vitamin B-12 into your circulatory system after bile from your gallbladder has neutralized the acidic chyme (what your partially digested food is called when it enters your small intestine). B-12 is vital for your red blood cells to carry oxygen. People who lack intrinsic factor, cannot absorb vitamin B-12 and suffer from pernicious anemia.

Chymosin, or rennin, is secreted by the chief cells in your stomach wall and is responsible for the breakdown of a specific peptide bond: phenylalanine and methionine, through a complicated chemical process that I won’t detail here. Interestingly, rennin is the active ingredient in rennet which is used the cheese production; compelling some vegetarians into eating cheese without rennet.

Gastric lipase (“lip” means fat and “ase” means breakdown) is secreted by the chief cells to begin fat digestion in your stomach by hydrolyzing (“hydro” means water and “lyzing” means breaking apart; so the breaking apart of a molecule using water) fat molecules into fatty acid chains. Further fat digestion happens in the small intestine with the addition of pancreatic lipase.

G-cells in the wall of your stomach secrete gastrin, a hormone responsible for stimulating the release of HCl from the parietal cells. Gastrin is a chemical messenger that travels in your bloodstream and is released when your stomach is distended from having recently eaten, or when directed to be released by your brain in response to the sight or smell of food. Gastrin stimulates the release of HCl and pepsinogen. It enhances the strength of your stomach contractions to aid in mechanical digestion and causes the pyloric sphincter to relax or contract, controlling movement of chyme that moves into duodenum, the first segment of the small intestine. Your duodenum can only process a certain amount of chyme at a time, so your pyloric sphincter opens and closes to allow small packets of chyme to enter at regular intervals.

In summary, your stomach breaks your food into smaller pieces and mixes it with all of the above secretions in mechanical digestion. Parietal cells secrete hydrochloric acid and intrinsic factor. Chief cells secrete pepsinogen, chymosin and gastric lipase. Mucus cells secrete mucus to protect the stomach wall from the acidic chyme. Gastrin is the hormone responsible for mobilizing the whole process.

The cecum is the small sac that connects to the ileum of the small intestine to the ascending colon. Chyme is the mostly digested food matter that enters the cecum from the small intestine. 90% of digestion has already taken place. The colon has no digestive enzymes, but positive intestinal bacteria called gut flora and mucus are added to the chyme to form feces. At this point, your body will reclaim water and vitamins; essentially concentrating the feces before it exits the body. Note; when you have watery poop, your colon is not reabsorbing water and vitamins from the feces; the last step in digestion is being skipped. This is one of the reasons why it is so important to stay hydrated when you have diarrhea.

One type of gut flora - Candida albicans

Now, a word about dietary fiber. We are constantly reminded to eat lots of fiber for colon health. But why? The bacteria in your large intestine consume the largely undigested fiber for their own sustenance, and give off acetate, propionate and butyrate as waste products which the cell lining of the large intestine uses as nutrients. It really is amazing how efficient our bodies are; the 3 R’s to the extreme.

What can go wrong?

Colitis (“col” is colon and “itis” means inflammation), not matter what the cause is a swelling of the large intestinal wall. It can caused by autoimmune processes, idiopathic (of unknown cause), vascular (an interruption of blood flow to a portion of the intestine), infectious (as is the case with clostridium difficile and e coli), or caused by parasites.

Hereditary or other causes of colorectal cancer affect approximately 7% of U.S. citizens.

Crohn’s disease is an autoimmune disorder where the body attacks the colon wall, causing colitis.

Major elements of the urinary system

The urinary bladder, as it is referred to anatomically to distinguish it from meaning “pouch or flexible enclosure”, sits atop your pelvic floor: protective layers of muscles and connective tissues designed to hold you internal organs in place. The bladder is the final internal destination for urine that has been collected and concentrated by the kidney and transported via the ureters – one for each kidney.

The urinary bladder; like the design of many other internal surfaces of your body, like the small intestine and the stomach is lined with folds of tissue. In the stomach and bladder, these folds are called rugae and they stretch and flatten in response to increased pressure – if you have just eaten a big meal or haven’t urinated in a long time. Our wonderful bodies follow this design because internal bladder expansion takes the pressure off the surrounding pelvic and abdominal organs. In contrast, if the bladder filled outwards like a balloon, our pelvic and abdominal muscles would be continually squashed.

We start feeling the urge to pee when our bladder is about 25% full. For most people; this pretty easy to ignore. Nerves on and near our bladder, when stretched, trigger the parasympathetic nervous system (the rest and digest part of our nervous system as opposed to the sympathetic fight or flight part of our nervous system) to signal us to go pee. As the bladder stretches, the PNS becomes more insistent that we go pee. If the bladder reaches 100% capacity you will expel urine involuntarily. The flow of urine is controlled by two muscles; an internal involuntary muscle called the detrusor muscle and an external voluntary Kegel muscle.

OK, a brief aside to explain involuntary and voluntary muscle: involuntary muscles are controlled directly by our nervous system without conscious input from us. They are made up of smooth muscle fibres. Skeletal muscle, under our voluntary control is also regulated by our nervous system, but we are the ones sending the signals to the brain to move or not move. Skeletal muscle is striated. Microscopically, they look very different from each other. Smooth muscles are working away in your body all the time; like for example, in your small intestine as the smooth muscles push food along the digestive tract towards the large intestine (or colon) and out the anus.

Kegel muscle a.k.a. the Pubococcygeus muscle

It is our voluntary muscle we contract to “hold pee in” You can strengthen this muscle by doing Kegel exercises – for women, flexing the little ring of muscles, inside your vaginal opening. Doing about 25 flexes of this muscle every day well help to prevent urinary incontinence problems when you are older. Men also have a Kegel muscle that allows their penis to stay erect, and controls their ejaculation and of course, help with incontinence. Men can isolate and strengthen this muscle by stopping and starting the flow when urinating. This is the same for women.

What can go wrong? Well it all boils down to incontinence, but for many different reasons. If you have damaged nerves, you may not be able to receive the PNS’s signals urging you to urinate as is the case with some Parkinson’s and Multiple Sclerosis patients. Your detrusor muscle (involuntary) is controlled by the PNS. If your PNS is damaged, this muscle may not function properly, and the only protection you have is your external muscle; which is likely not strong enough to hold back small outputs of urine. Prostate cancer can damage pelvic nerves resulting in incontinence.

Sometimes (mostly in women), if you laugh, sneeze or cough, the pressure it creates overcomes both sets of muscles resulting in little spurts of urine coming out. This is called Stress Incontinence and happens mostly in older women – over the age of 60, but can happen younger; say if you have a genetic predisposition to urinary incontinence.

Overactive bladder is diagnosed when you have to pee 8 or more times a day, and are up 1 or 2 times a night. Based on this definition approximately 1 in 6 people in the U.S. have this problem. OAB can be treated with antimuscarinic drugs or through a really cool sounding procedure whereby physicians insert an electrode near the tibial nerve in your leg. An electrical impulse travels to your sacral plexus via your tibial nerve. Recall, that your tibia is a bone in your lower leg. Your sacral plexus is a bundle of nerve fibers responsible for controlling parts of your pelvis and lower extremities. The treatment takes place once a week for 12 weeks. Some patients need more or ongoing treatment. I myself have an overactive bladder, but it doesn’t badly interfere with my life – excepting 11 hour long bus rides in Central Turkey with only one bathroom stop; I have just lived with it without treatment. Please understand, I am not a medical professional and I am not advocating any procedure or treatment, but just seek to educate people about our bodies and how they work. Peace out.

The thyroid produces T3 and T4; triiodothyronine and thyroxine for those of you who like wordy words as well as calcitonin. As their name suggests, both T3 and T4 use iodine, and their numbers refer to how many iodine molecules are attached to the structure. Detailed and easy to understand information about the thyroid is hard elusive and I find myself having to refer to my anatomy and physiology textbooks to provide the best answer. Your thyroid has two different kinds of follicle cells – cells that secrete hormones: follicular cells and parafollicular cells. Your follicular cells produce T3 and T4.

Your pituitary gland is located in your brain and secretes, among other things Thyroid Stimulating Hormone (if it is a stimulating hormone, it comes from your pituitary gland). TSH tells your thyroid to make T3 and T4 which travel to every cell in your body and stimulate those cells to produce protein or increase oxygen usage.

The thyroid’s parafollicular cells produce calcitonin which decreases the amount of circulating calcium in your blood. To help you remember this, think “calcitonin tones down the body’s calcium.” Your body does this by storing the excess calcium in your bones, and interestingly, calcitonin contributes to us no longer feeling hungry. There are times also, when you need to increase the amount of circulating calcium. The parathyroid glands that sit atop the thyroid secrete parathyroid hormone to stimulate our bone cells to release calcium, by stimulating our kidney to reabsorb calcium in the process of urine concentration, and stimulates our small intestine to absorb more calcium from the food we eat via Vitamin D. Essentially, the small intestine asks the kidney for a usable form of Vitamin D which enhances the absorption of calcium by the microvilli in your small intestine. The production of parathyroid hormone is not dependent upon a feedback loop with the pituitary gland in your brain. Sensors on the parathyroid gland themselves can measure the amount of circulating calcium in the blood.

There are lots of different disorders associated with the thyroid, but almost all of them break down into too little or too much thyroid hormone. The cause can be linked to a problem with the thyroid itself, or a problem with the hypothalamus or pituitary gland in your brain. Whatever the case, symptoms are similar.

Hypothyroidism is a deficiency of thyroid hormone. Although, as I stated, there are many causes, the most common cause is iodine insufficiency  (the introduction of iodized table salt into our collective diet has helped with this problem). Since T3 and T4 are responsible for cellular metabolism, our body doesn’t metabolize our food properly, nor does it get the boost in energy that increased oxygen production supplies; leading to weight gain, tiredness, cold intolerance, muscle cramps, joint pain, carpal tunnel syndrome,decreased sweating, brittle hair and nails , constipation and a low heart rate. Hashimoto’s thyroiditis is an autoimmune disorder that causes hypothyroidism, and ironically, the drug treatment for hypER thyroidism can cause hypothyroidism.

Hyperthyroidism in an excess of thyroid hormone that lead increases metabolism beyond a healthy level. This results in stimulating the body’s sympathetic nervous system (the getting ready for fight system fueled by adrenaline). This exhibits as fast heart beat, palpitations, tremor, anxiety, diarrhea and weight loss – not a good diet plan. Grave’s disease is the most common presentation of hyperthyroidism.

Red blood cells; the cells responsible for carrying oxygen to the body’s tissues, have a life span of about 4 months before the wear out. The monocytes in the spleen collect dying rbc’s and to recycle their constituents for use in the body. What can’t be recycled, is excreted by the kidneys and large intestine. Both urine and feces get their trademark colors, in part, from the waste products of red blood cells bilirubin and biliverdin. Monocytes are white blood cells that can either directly destroy dead red blood cells though a series of surface membrane chemical reactions or can differentiate into macrophages which resemble gobbling Pac-Men. Half of the body’s monocytes are stored in the spleen. Monocytes also travel through your body and migrate to damaged tissues when needed. Monocytes differentiate (mature) into macrophages to “eat up” dead cells, bacteria, or other waste products from damaged tissues.

Human Monocyte surrounded by red blood cells

The spleen’s monocytes are also responsible for eating up antibody coated bacteria and cells. Think of antibodies as little “please kill me” signs attached to the outside of cells. The body’s immune system has marked these antibody complexes for destruction. Monocytes will either ingest these complexes directly, or cause them to self destruct.

You can live without your spleen, but its absence will leave you more susceptible to infection. Splenectomy patients have a higher than average rate of death from pneumonia and a higher concentration of circulating monocytes – since their storage unit has been removed. Splenectomy patients also show a decreased response to some vaccinations. Without your spleen, you need to work harder to stay healthy to prevent disease.

The small intestine receives partially digested food from your stomach. At the point when food reaches the duodenum of the small intestine, it has been mixed with stomach acid and manually broken up by the contraction of the stomach walls. The smaller the pieces of food, the better able your body is to absorb the nutrients because many small pieces of food have much greater surface area than fewer large pieces of food. This surface area allows for greater exposure to the microvilli of the small intestine to absorb the maximum possible number of nutrients. Let’s examine how the body deals with carbohydrates, fats and proteins in the small intestine. Microvilli are small, finger like appendages attached to the larger villi that line the walls of your small intestine. Combined, the microvilli and villi increase the surface area inside your small intestine to 500 meters squared, whereas, if the intestinal walls were smooth with no ridges, the surface area would only be 1/2 a meter squared. Think of your microvilli as little nutrient vacuums inside your small intestine.

Fats

Lipid molecules (lipid means fat) must be broken down into very small globules in order to be taken up by the microvilli in your small intestine. Pancreatic lipase (“lip” refers to fat and “ase” means the “breaking down of”) is made in the pancreas and secreted through the pancreatic duct into the duodenum, the first portion of the small intestine after the stomach. Lipase is aided by bile from the gallbladder. Bile orients the fatty acids so that their hydrophobic (“water fearing”) heads point towards each other in the center, away from the watery intestinal walls, to allow the pancreatic lipase to break down triglycerides (fancy name for fat molecule) into glycerol and free fatty acids which can be absorbed by the microvilli.

Carbohydrates

Starchy and sugary foods consist mostly of carbohydrates. Carbohydrates are long strings of sugar molecules. Pancreatic amylase breaks down starch molecules into oligosaccharides. Then, sucrase, lactase and maltase (remember “ase” means the “breaking down of” and sucrose, lactose and maltose are different types of sugar molecules), break down the smaller components into molecules that can be absorbed and used in the body. It is interesting to note that lactase is absent in many adults; thus rendering them “lactose intolerant”. Lactose is the sugar in milk. Without lactase, our intestines are unable to digest milk products, resulting in a gaseous, upset, sick feeling, with diarrhea, and flatulence.

Protein

Protein digestion begins in the stomach with chemical and mechanical breakdown into smaller protein pieces and polypeptide chains. A protein is a long peptide chain (poly means “many”). Polypeptides are long chains of amino acids. Amino acids are absorbed by the microvilli of the small intestine. The pancreas secretes trypsin and chymotrypsin into the duodenum of the small intestine to break down proteins into amino acids.

How Does Absorption Happen?

Within the microvilli of the small intestine are networks of capillaries and lymph vessels called lacteals. Capillaries are the smallest components of your blood vessels, the site at which your blood exchanges nutrients, oxygen and waste products with your body’s tissues. Simply put, nutrients diffuse into your blood vessels through chemical and electrical gradients: in a very short, very oversimplified summary, substances will move from an area of high concentration to an area of low concentration and the cells in our tissues facilitate this by changing their chemical concentrations and electrical charges. Fat molecules are taken up by lacteals; little balloons of lymph tissue that merge with other lacteals to form lymphatic vessels responsible for circulating lymph fluid. Lacteals make it into our bloodstream for distribution to our tissues via the subclavian vein (sub = under and clavian = clavicle). Fats in the bloodstream are called chylomicrons.

Not all digested matter from our food makes it to the bloodstream. Whatever is left after our small intestine sucks out all of the nutrients passes onto our large intestine. Here, water and salt are reclaimed for the body, the waste is concentrated and comes out our anus as stool. What I find really interesting is that between the mouth and the anus is one, long continuous, open ended tube. What goes in, must come out. At risk of being too gross, I will mention that the color of your stool can be indicative of a number of illnesses of the pancreas, the liver, the gallbladder and more; since the color of stool is dependent both upon what we eat and what we use to digest food. for example, grey or whitish stool can indicate a problem with your liver or gallbladder. What can your poo tell you?

There are many different types of T-cells, but one of the best known to us are memory T-cells; as their name suggests, they are responsible for our immunity to certain diseases through vaccinations. B-cells make the antibodies that fight  antigens (foreign cells). In short, T-cells have the recipe and B-cells are the cooks. Natural killer cells attack viruses and tumor cells.

Although, current knowledge of the role of our appendix is based on well educated guesses, here is what we know:: our appendix may have played a role in helping our distant relatives digest plant matter; a mainstay of their ancient diet; by storing additional digestive enzymes. Scientists base this knowledge on the comparison between the human appendix and the koala bear appendix. The appendix is rich in lymphocytes as stated above. Finally, the appendix may play an important role in repopulating natural bacteria to our large intestine that are wiped out by diarrhea and other similar illnesses.

Why do so many people undergo an appendectomy?

Partially digested food and foreign antigens can become stuck in the appendix because of its remote location. Your appendix is a closed tube, making it difficult for your body to clear away debris, should any infection causing bacteria or other matter become stuck. It used to be routine practice to remove the appendix during any abdominal surgery due to its propensity for becoming infected and the deadly consequences that could result from this infection. If an infection continues without treatment, your appendix could rupture, spewing out bacteria laden materials into your peritoneum and abdominal cavity, possibly resulting in sepsis and death. Rather than take this risk, doctors used to routinely remove the appendix, but current medical practices include giving IV antibiotics to treat appendicitis (“citis” means inflammed), that can lead to a full recovery. It is worth noting, however, that most people don’t notice any difference in their body’s immune functioning after having their appendix removed.

This article is for Mike

We all know the simple answer; it pumps blood, but how exactly does it work. Let’s piggy back on a red blood cell and follow its journey as it leaves the lungs with a fresh supply of oxygen. But first, understand there are many components that make up our blood including plasma, red and white blood cells, platelets and nutrients from our food.

Freshly rejuvenated with a  supply of oxygen from the alveoli in our lungs, the rbc enters the left atrium of the heart via the pulmonary veins. Although undetectable when checking your own pulse; your heart actually has two sets of contractions; atrial and ventricular systole. The left atrium contracts to force the newly oxygenated blood into the left ventricle via the mitral valve; while at the same time, the right atrium contracts to force deoxygenated blood into the right ventricle en route to the lungs. During ventricular systole, the left ventricle contracts, forcing the oxygen saturated rbc into the superior (upper) and inferior (lower) aorta for distribution through your body. There are special valves that close to prevent back flow into the atrium during the powerful ventricular systole. Some people have a disorder called a heart murmur, where their mitral valve doesn’t close properly and blood from the ventricle flows back into the atrium. In aortic stenosis, the aortic valve doesn’t close completely and blood doesn’t properly leave the ventricle forcing the heart into a number of compensatory mechanisms, some of which cause ventricular hypertrophy; an enlargement of heart muscle. Simply put, a muscle working hard will get bigger, much like weight lifters building body muscle mass.

The aorta immediately branches into the ascending and descending aortas; to distribute blood to the upper and lower body.  At rest, the blood flow percentages to the body are as follows: 4-5% is used by the heart muscle itself, 21-22% is used by the kidneys, 18% is used by the skeletal muscles (during exercise, the skeletal muscles use 71-72% of our total blood flow), 7% by our skin, 25% by our viscera, 13% by our brain (consider that the brain only makes up 1/50th the total mass of our bodies), 11-12% by the rest of our bodies.

Our red blood cells exchange oxygen for carbon dioxide; a waste product of cellular respiration. This carbon dioxide needs to be transported back to our lungs via our veins for us to breath out. The easiest way to remember which vessel carries which type of blood is to associate our arteries with “away”; in that arteries take blood away from the heart. Veins transport blood back to the right atrium of the heart via the superior and inferior vena cava. Veins always bring blood to the heart. Our red blood cell has exchanged its oxygen for carbon dioxide and now needs to return to the lungs for refueling.  From the right atrium, into the right ventricle and back to the lungs via the pulmonary arteries, the indispensable red blood cell has completed one full circuit through our bodies.

Interestingly, the “lub dub” sounds heard through the doctor’s stethoscope are the closing of the valves of the heart; the bicuspid (a.k.a mitral) and tricuspid valves that separate the right and left atrium from the right and left ventricle, and the semilunar valves that prevent back flow into the ventricles once the blood has been forced out into the aorta and pulmonary arteries.

What is an Electrocardiogram or ECG?

The ECG measures electrical impulses traveling through the heart. The heart contracts based on a signal generated by the sinoatrial node (SA), and continued by the atrioventricular node (AV). The SA node is our pacemaker; it sets the normal sinus rhythm of our heart. The electrical impulse travels to the AV node which conducts this impulse from the atria to the ventricles. This sinus rhythm is what causes the contraction of the heart muscle. While, the cells that generate the electrical impulse are heart muscle cells, they, themselves do not contract. To me, this is the beauty of the body at work; real magic.

The normal sinus rhythm is represented by a series of peaks and depressions on graph. The P-wave is the current traveling between the SA and the AV Nodes. It is worth noting that the spikes on an ECG reading don’t represent the physical contraction of the heart muscle, but rather the flow of electrical impulse through the myocardium (“myo” means muscle and “cardium” means heart). The QRS segment is the depolarization of the ventricles and the T-wave is the repolarization of the ventricles – allowing them a brief state of rest before the next impulse occurs. Doctors can diagnose potential heart problems and their approximate location based on disruptions in these waves.

Whenever I think about how people abuse their bodies with substances, I marvel at the heart’s marvelous capacity for being both an incredibly precise and terribly complicated machine and one of incredible power. If you live to be 80, your heart will beat between 2 and 3 billion times. There is no machine I can think of more efficient than that!

Exocrine Functions

An exocrine organ secretes substances that leave your body – think “exit” and “exocrine”.  Your digestive tract is one long tube, open at both ends that receives enzymes and other materials to enable nutrient absorption. Mammary glands produce milk and mucus glands secrete mucus; all of which are destined to leave the body. In contrast, endocrine organs secrete chemicals into the bloodstream for use by the body. The adrenal glands release adrenaline into the blood to physically prepare us for danger.  The hypothalamus produces a myriad of hormones to regulate bodily functions.

The liver produces bile that is stored in the gallbladder to be secreted into the small intestine before eventually leaving the body; making bile production an exocrine function. Bile emulsifies fats – breaks the large lipid molecules into smaller pieces, creating more surface area to ease digestion. This is why people without gallbladders can’t have a lot of fatty foods at one time. The liver is able to produce enough bile for immediate use, but can’t stockpile enough bile to digest a Big Mac and large fries.

Your liver also manufactures some very important hormones (endocrine function). It produces Insulin-Like Growth Factor (IGF 1); a hormone responsible for stimulating body growth in children. Thrombopoietin is a hormone produced by the liver that regulates platelet production in your bone marrow. “Thrombo” refers to blood clotting and “poietin” refers to stimulating cell multiplication. I am a big believer in breaking down words into their roots. The body becomes much easier to understand if you know anything “hepatic” is pertaining to the liver, “angio” to the heart, “renal” to the kidneys and so on.

Your liver, along with your kidneys, are an important organ in glucose metabolism. The liver converts glucose into glycogen. Glycogen provides the body with short term energy storage. Long term energy storage is contained in fat cells. Muscle cells can also convert glucose to glycogen. “Gluco” refers to sugar. The liver converts glycogen back to glucose for immediate use. Gluconeogenesis is the process of making glucose (genesis) from “new” products. Specifically, this refers to making glucose from amino acids, lactate and other non-sugar substances. Gluconeogenesis occurs in times of fasting and exercise – generally after all easily available reserves have been used up. To summarize, glycogenesis is the opposite of glycogenolysis (lysis means to break apart).

The liver makes cholesterol and tryglycerides; important components of hormone production. Thank your liver for those elevated cholesterol levels. Through a relatively complicated chemical synthesis, the liver converts glucose into triglycerides by attaching a glycerol to every three glucose. Cells in the body use triglycerides in their endoplasmic reticulum; the site of protein and hormone production (endo means inside and plasma refers to the cytoplasm inside a cell). Fatty liver is a disease in which the liver enlarges with excess triglycerides. Since the liver is the site of triglyceride manufacture, a vicious cycle occurs when the body has too much glucose, the liver busily makes the glucose into triglycerides at an increased rate to match those higher levels. The body uses as much triglycerides as it can, and the rest builds up in the liver; having no where else to go. Alcoholism and obesity are common causes of fatty liver disease. Do you eat fois gras? You are eating the diseased liver of obese birds. Farmers force feed geese and ducks corn boiled in fat to create fatty liver disease. It is the excess fat that gives their liver the rich and buttery taste. There are major ethical debates world wide about this practice, but I digress..

The liver is where old red blood cells go to die.  Bilirubin and biliverdin are waste products from red blood cell metabolism. Some is added to bile to aid in fat digestion and some is filtered through the kidneys to give  urine its trademark yellow color. The bile portion makes its way through the small and large intestine to give feces its trademark brown color. Jaundice, the disease in which the skin and eyes become  yellow results from a blood excess of bilirubin. The liver normally collects and secretes bilirubin into bile, but if it is not functioning properly, bilirubin builds up in your blood and becomes toxic.

The liver is the site of drug metabolism and in some cases drugs can become temporarily more toxic to the body during the digestion process as their constituents become more concentrated. Some drug metabolites are secreted into bile and others into urine. In addition to drug metabolism, the liver has cells that filter antigens out of the blood. Anti in this case refers to antibody and gen refers to generating; so antigen literally means “antibody generating”. The liver is one of the many immunological organs in the human body.

The liver stores vitamins and minerals for short and long term use including Vitamin A, Vitamin D, Vitamin B12, iron and copper and in case I haven’t already made a case for taking care of your liver, be aware that it is responsible for making albumin, the plasma protein responsible for maintaining blood osmolarity – the concentration of dissolved solutes for a given amount of liquid. If your blood osmolarity is out of whack, you risk bleeding internally. The cells in your body will either shrink up and die from losing water or swell up and burst from taking in too much water.

One more major function; the liver makes angiotensinogen, a precursor to angiotensin, the hormone responsible for increasing blood pressure in times of fluid loss, or elevated blood cortisol levels.

With all of these major functions, it is a wonder that we don’t get sick with liver related problems even more than we already do. Take  heart (or liver – tee hee); the liver is the only human organ capable of regeneration. You can grow a new liver from only 25% of a full liver! Someone doesn’t have to die for you to receive a transplant!

The pancreas is both an exocrine and endocrine organ. Endocrine glands release hormones into the blood in order to cause an effect in some part of the body. For example, the pancreas releases insulin in response to high blood sugar and the adrenal glands that sit atop the kidney secrete adrenalin, the “fight or flight” hormone. Exocrine glands release enzymes through ducts and include mammary glands, salivary glands, sweat glands, and glands that secrete digestive enzymes into your stomach and intestine. A main difference is that the exocrine glands release fluids that will exit the body, either through the digestive tract, the skin, the nipple or the mouth, whereas endocrine glands are an internal messaging system.

Where is the pancreas? It is located behind the liver and mostly on the right hand side of your body.

What hormones and enzymes do the pancreas secrete and what roles do they play in the human body? The pancreas make two competing endocrine hormones that play an important role in diabetes, hypo and hyperglycemia. Hypo refers to a low level, “glyc” refers to glucose and “emia” always refers to blood. So hypoglycemia literally means low sugar in the blood. Hyperglycemia is high blood sugar. I think of hyper kids to remember an excess of something. Both hypo and hyper can be used to describe the state of many organs in the body. Hypo and hyperthyroidism, hypo and hypercalcemia (low or high blood calcium), hyperhidrosis (excess sweating).

The pancreas makes insulin, the hormone responsible for controlling the amount of glucose in the blood. If you eat a caramel apple, your blood will temporarily be high in glucose until the insulin facilitates metabolism. The pancreas also make glucagon (I think of glucose being gone from the blood to remember this). Glucagon is released when your blood sugar drops too low and stimulates your liver to convert stored glycogen to glucose for the blood to take to cells in your body. Remember that the glycogen was stored by the liver when our body produced insulin in response to eating a food high in sugar. Both of these hormones come from the endocrine part of the pancreas known as the islets of Langerhans. These islets are made up of alpha and beta cells. Alpha cells secrete glucagon and beta cells secrete insulin.

The exocrine structures in the pancreas are called Pancreatic acini. There are four digestive enzymes that are secreted from these acini into the digestive tract: pancreatic lipase helps in the digestion of fats (lipase stems from lipid and anything with “ase” at the end will be some sort of enzyme – that goes for the whole body). Specifically, pancreatic lipase emulsifies fat (a fancy word to describe making the fat globules smaller so that the fat can be taken up by the blood). Pancreatic amylase breaks down starch into sugar; starches are simply long chains of sugars. Trypsin breaks down proteins into peptide chains and Chymotrypsin breaks down peptide chains into amino acids.

Knowing all of this, you can see why having a problem with you pancreas can quickly become deadly. What can go wrong? Diabetes is a condition where insulin is either non existant or inadequate in supply. Type 1 diabetes, the beta cells in the pancreas have been destroyed and you are no longer able to make insulin. Daily injections of insulin are necessary to digest sugar and sugar intake must be monitored closely. Type 2 diabetes is a condition that usually develops later in life and is characterized by low insulin levels and high blood sugar. This disease develops as a result of both a genetic predisposition, and lifestyle factors that contribute to the body building up a tolerance to insulin so that higher and higher levels are needed to maintain a normal blood sugar. Eventually the pancreas can’t keep up with demand and unless a significant change in lifestyle is made. Sometimes Type 2 diabetics will need to manage the disease with insulin injections.

Pancreatitis is literally an inflammation of the pancreas; the term “itis” refers to something that is inflammed. It can either be acute or chronic. Acute pancreatitis has a sudden onset and needs immediate medical intervention. It is most often caused by alcoholism and gallstones. Chronic pancreatitis is usually caused by long term alcohol abuse. A quarter of cases have no known cause.

Adenocarcinomas are the most common form of pancreatic cancer. They are neoplasms of the glandular tissue; the tissue responsible for secreting digestive enzymes. This is a particularly deadly form of cancer. Less than 5% of individuals are alive after 5 years and remission is extremely rare.

Cystic fibrosis, in addition to all of the other nasty effects it has on the body, causes cysts to form in the pancreas, resulting in permanent damage and painful, chronic inflammation.

There are other things that can go wrong with your pancreas; I have just touched on the main problems. I don’t want to contribute to hyperchondria!