The Digestive System

The Digestive System

The Digestive System For we are all, really, just doughnuts J. Schwieger Alimentary Canal The alimentary canal is the mucous membrane-lined tube of the digestive system. This is the tube where digestion

takes place, and from which wastes are eliminated. It extends from the mouth to the anus and includes the pharynx (throat), esophagus (gullet), stomach, and intestines. It is also called digestive tract. . Mouth Teeth and saliva begin digestion process Tongue pushes

and helps to manipulate food so it can be masticated properly Uvula is an extension of the soft palate: it helps to cover the nasal passages Cougar Skull Cougars are also diphyodonts and heterodonts. Their molars (carnasial teeth) overlap each other to allow for a

scissors like cutting action. The incisors are for catching and holding. Wolf Skull - note the same carnasial molars. Wolves are diphodonts as well. Brown Bear Skull - note the crest on the skull for the mandible muscle. Sperm Whale This is the lower jaw of a Sperm Whale on display in a museum in Maine. One of the jaws on display is 18 feet long! The teeth can be 6 inches

long! Whales teeth are all the same. They get only one set. It is estimated that this individual was 75 feet long and weighed 60 tons (120,000 lbs.) Sperm Whale Juvenile Male This 33 foot individual was photographed near the Bonin islands in the Pacific. Their teeth are adapted for holding the squid and fish they catch during their deep, hour long dives. This male could grow as

long as 80-85 feet and weigh as much as 70 tons (140,000 lbs.) They are the largest carnivore on the planet and they have the largest brain of any creature ever known. Scrimshaw Scrimshaw is drawings done on Sperm Whale teeth. They have become rare and valuable collectors items. These two examples are from the JFK museum. The teeth are

approximately 5 inches long. Ivory Ivory is a hard, white, opaque substance that is the bulk of the teeth and tusks of animals such as the elephant, hippopotamus, walrus, mammoth and toothed whales. Prior to the introduction of plastics, it was used for billiard

balls, piano keys, buttons and ornamental items. The word "ivory" was traditionally applied to the tusks of elephants. The chemical structure of the teeth and tusks of mammals is the same regardless of the species. Elephants In contrast to humans, elephants get 6 sets of molars. Teeth are not, however, exchanged from the bottom to the top (vertically), as in humans and most mammals, but rather from the back to the front (horizontally).

Elephant calves are born with approximately 2 small molar teeth, about the size of a thumbnail, in both the upper and the lower jaw. In the course of time the molar tooth next in size slowly moves from the back to the front and thus replaces the old tooth. Elephant Graveyard When the last tooth is worn down, it becomes difficult for elephants to chew their food properly. Then they usually start to look around for softer

vegetation, which grows in the swamps. In the end old elephants succumb to their weakness and die at the water's edge. Old elephants' inclination to die in one and the same area has enabled the rise of the fairy tale and myth of the elephant's graveyard.

Elephants' tusks correspond to other mammals' incisor teeth. One of the tusk's unique characteristics is that it does not have a coat of dental enamel. Two thirds of a tusk is visible. The first third is lodged in the skull's tooth socket. Two thirds of the tusk are 'alive'. This means that they have pulp cavities which are filled with a tissue which has an abundance of blood vessels and branches of nerves. This is why tusks are sensitive to pressure and blows. A tusk breaking off can have disastrous consequences for the

elephant concerned. In the worst case if the odontic nerve and the pulp are exposed the animal dies of the enormous pain. What are tusks? Crocodile teeth Teeth grow in a socket.

If the tooth is lost a new one will grow from an adjacent socket. Once that tooth is lost it cannot be replaced. Crocodiles grow continuously throughout the lives. The largest ever recorded is a specimen of the Salt Water Crocodile. It was captured in a river in Northern Australia It was 26 feet long and weighed 4,000 lbs. The jaws measured 6 feet long. Teeth Enamel is composed

of CaPO4 and CaCO3 Dentin is hard and calcified, though not as hard as the enamel. Connective tissue called pulp fills the pulp cavity within the crown of the tooth. The joint between the teeth and the gums is a fibrous joint. Problems with teeth include, not having a 2nd set, not having a baby tooth, wisdom teeth problems, decay, cracking and breaking

and gum disease. Found in your mouth and throat. The main ones secrete

saliva into your mouth through ducts. About 1 to 1.5 L/day. 99% is water. Main enzyme is amylase to assist in the digestion of starch. Also mucins, lysosomes, urea and bicarbonates to control pH Parotid through ducts near upper teeth. Submandibular through ducts under your tongue Sublingual through many ducts in the floor of your mouth. Salivary Glands Diseases of Salivary Glands

Stones can collect and block the ducts. Most common salivary gland infection is mumps. (parotid glands)(virus) Infections can pass from lymph glands Cancer is rare, painful and treatable. Pharynx Common tube for food and air (nasopharynx,

oropharynx and laryngopharynx.) Epiglottis reflexively closes over the opening of the trachea so food and liquids do not go to lungs (aspiration) Spasm of diaphragm is hiccups. Uvula extension of soft palate. =Ww0YTjA1f0E Esophagus

Function; transport food to stomach. Soft palate (uvula) closes over nasal cavity. Laryngopharynx epiglottis - prevents food from getting into lungs. Cardiac sphincter prevents stomach material from backflowing into esophagus. Deglutition - swallowing Voluntary - tongue pushing food, Involuntary - esophagus contracting to push food to

stomach. Not well protected from harsh chemicals. Esophagus Muscular tube leading to stomach. Two layers of muscles longitudinal and circular Peristalsiswavelike motion of esophagus to push food to stomach Harmon Killebrew and Esophageal cancer He died of this disease last summer. According to the National Cancer Institute, there were

16,640 cases of esophageal cancer, and 14,500 deaths from the affliction in 2010. His symptoms included loss of weight and difficulty in swallowing. All the causes aren't known, but some of the leading risk factors for the disease include smoking, obesity and heavy alcohol consumption. This is a disease that commonly occurs after age 55. It is more common in men than women.

High acidity (pH = 2) allows enzyme pepsinogen to start protein digestion. Three layers of muscles to churn and mix the bolus. Does not absorb a lot of material (alcohol, aspirin) Destroys most harmful materials.

Specialized cells produce alkaline mucus to protect itself. Food remains in the stomach 3-4 hours. The chewed food (bolus) becomes chyme. Hiatal Hernia

A situation where part of the stomach extrudes above the diaghragm. This can cause the cardiac sphincter to leak stomach fluid into the sensitive esophagus. This leakage can cause burning, heartburn and even lesions or ulcers. Symptoms include belching, nausea, chest pains and difficulty taking a deep breath.

At any one time, about one in 25 adults will have an active stomach ulcer. During their lifetime one in 7 men and one in 12 women will have this potentially serious condition. Ulcers are areas of damage to the lining of the stomach, as in a

gastric ulcer, or the upper part of the intestine (duodenal ulcer). A number of factors cause ulcers. These include prolonged use of antiinflammatory drugs (often used to treat arthritis), smoking, alcohol, diet and stress. Ulcers Ulcers

The symptom of an ulcer is pain in the upper part of the abdomen just below the breast bone. The pain generally occurs when the stomach is empty. The pain is often relieved by food or antacid medication. More serious symptoms occur if the ulcer bleeds. On rare occasions an ulcer will perforate

through the stomach or duodenal wall. This is a major emergency requiring surgery. Most ulcers respond well to treatment with drugs which heal them.

This is a bacterial organism that is responsible for many stomach diseases. It enters the body through infected food and the bacterium hides in the mucus layer of the stomach protecting itself against the low pH of the stomach. With stomach ulcers, H. pylori infection is found in 60 to 80 percent of the cases. It is still uncertain how the infection acts to cause the ulcer. It probably weakens the protective mucous layer of the stomach. This allows acid to seep in and injure the underlying stomach cells.

There is still a great deal of research to be done to unravel this relationship. Heliobacter pylori A large fold of connective tissue that hangs down over the intestines and

interconnects the stomach, duodenum and the large intestine. It can have lots of adipose tissue (fatty apron) Contains lymph nodes which help fight infection and prevent its spread to the peritoneum. Falciform ligament, attaches the liver to the diaphragm. Lesser omentum suspends to stomach and the first part of the duodenum Greater Omentum

The diaphragm is a thin domeshaped muscle which separates the thoracic cavity (lungs and heart) from the abdominal cavity (intestines, stomach, liver, etc.). It is involved in respiration, drawing downward in the

chest on inhalation, and pushing upward in exhalation. Diaphragm Elongated organ containing exocrine (ducted) and endocrine glands.

Exocrine - digestive enzymes through pancreatic duct into the duodenum. Endocrine - insulin which is produced from cells in the pancreas called the islets of Langerhans Insulin helps the cells of the body absorb glucose from the blood. In the absence of insulin glucose levels in the blood increase to dangerous levels and the excess has to be removed via the kidneys. This disease is called diabetes. Pancreas

Endocrine cells which produce insulin. For some reason, which seems to have a genetic tendency, these cells stop producing insulin in some people. This usually occurs in young children and teens. This is called Juvenile

onset Diabetes.(Type 1 Diabetes) These people afflicted with this disease will need to take insulin the rest of their lives. Fortunately there is plenty of human insulin made available through genetic engineering. Islets of Langerhans

There are 18.2 million people in the United States have diabetes. An estimated 13 million have been diagnosed, Type 2 diabetes is the most common form of diabetes. In type 2 diabetes, either the body does not produce enough insulin or the cells ignore the insulin. New technology like the insulin pump pictured here allows the diabetic to do a better job of maintaining a constant

blood sugar level. The hope for the future may be in the success of transplanting islets of Langerhans cells. Diabetes Liver Largest gland of body (1500 g)

Removes excess nutrients from blood, transforms glucose to glycogen or fat. Synthesizes plasma proteins and blood clotting proteins Detoxifies alcohol and other poisons Destroys bacteria and old RBCs Helps to activate vitamin D. It stores iron, copper, and certain vitamins (A, D, E, K. B12) Hepatocyte stores glycogen, Vit. A, B12, and Fe. Makes plasma proteins, metabolizes fat soluble compounds (drugs, insecticides).

Secretes bile (1 L/day) Kupffer cells - specialized cells in the liver that destroy bacteria, foreign proteins, and worn-out blood cells. Stellate cells when activated produce collagen and scar tissue for an injured liver. A chronic liver disease which damages liver tissue. This includes scarring of the liver (fibrosis; nodular regeneration), progressive decrease in liver function,

excessive fluid in the abdomen (ascites), bleeding disorders (coagulopathy), increased pressure in the blood vessels (portal hypertension), and brain function disorders (hepatic encephalopathy). Excessive alcohol use is the leading cause of cirrhosis. Cirrhosis is a serious condition. Only 30 per cent of patients with this problem will survive five years after diagnosis and the outlook is worse if the cause is alcohol and the patient continues to drink. Cirrhosis of the Liver

Live donor liver transplantation (LDLT) is a procedure in which a living person donates a portion of his or her liver to another. LDLT was first demonstrated in the United States in 1989. The recipient was a child, who received a segment of his mother's liver.. Liver Recipients Patients being considered for LDLT are those who are candidates to receive a cadaveric liver. These patients are placed on the liver transplant waiting list and will not be denied a donor liver if it becomes available prior to LDLT. Thus, failure to find a suitable donor for LDLT will not jeopardize the

recipient's chances of receiving a cadaveric liver Basic Facts about the liver donor The donor could either be a relative or even unrelated. The blood type should be the same as the recipient's. The donor should be in good physical and mental health.

The decision to be a donor should be made after careful consideration of facts and knowledge of the procedures, the risks and complications. The donor must be relatively close in size (or larger) than the recipient. It is rare, but not unheard of for a donor to die during this process. A good donor is someone who is in good physical and mental health, older than the age of 18 and free from:

HIV infection Known viral hepatitis Active alcoholism with frequent and heavy alcohol intake Psychiatric illness under treatment History of malignancy Heart and lung disease requiring medications

Diabetes mellitus of greater than 7 years duration Liver donors Donor Recovery The donor is in the intensive care unit for about 24 hours and in the hospital for 5-7 days. Most patients are up and out of bed (with assistance) by the second or third postoperative day. It is necessary to stay off work and usual home activities for a month full time.

After that, 2 to 4 weeks part time, depending on the rapidity of the recovery. After 3 months donors are living a normal life. Two teams perform the donor and recipient operations simultaneously. As the diseased liver is removed from the recipient by one team, approximately half of the donor's normal liver is removed by the other team. Once the donor operation is completed, both teams complete the transplant by attaching the half-liver into the recipient.

The donor operation takes about 5 hours and the recipient operation about 10 hours. Both half-livers (of donor and recipient) grow to be full sized in 6-8 weeks. Performing the Operation Recipient Recovery After 2 days in intensive care the recipient stays in the hospital for another 10 days. For the first few weeks frequent checks are needed. Weekly lab work is done for the first 4 months. Liver transplantation requires a lifelong

commitment by the patient and family. This includes taking medications daily, visiting a physician regularly, eating a proper diet, maintaining an exercise program and trying to avoid infections. Holly Werlein, 25 liver recipient Hollys story part 1 I never thought in a million years that I would go through something like this. My story isn't like most peoples who unfortunately had to wait. I am one of the rare few that went through acute fulminate liver failure. I just happened to be in the right place at the right time. I was at the Cleveland Clinic for a totally unrelated appt. and my mom noticed my eyes were yellow. I hadn't been feeling all the best, upset

stomach, fatigue and just figured it was nothing. Well my doctor had my liver enzymes tested and they were in the thousands, so she immediately admitted me. I thought this was crazy! They tested me for everything possible and couldn't find anything wrong. Hollys story part 2 Our 2 day trip turned into an unexpected month long stay at the hospital. I remember 3-4 days in the hospital and the rest is vague memories, until I woke up! I had no idea I had a liver transplant! Apparently, my parents told me, I was telling docs I was in Florida. They thought my liver was going to regenerate since I was so young, but the toxins continued to build up and finally docs realized that after a liver biopsy. I was immediately put on the list 1st in the nation for a liver. Miraculously, they found one in 8 hours and I was transplanted with no time to spare. It's amazing how quickly this all happened and they never figured out the cause of my liver

failure, which is scary. They said it had shrunk to 1 lb and had brown spots on it, which is weird. Hollys story part 3 My recovery was quick at first, but I went through good old rejection about 2-3 weeks after. I had to be airlifted from Michigan back to Cleveland. They put me on high dose IV steroids for 2 weeks and by then I was ready to get out of there. Ever since that episode, I've been doing well and have participated in the US and world transplant games. My family has been my rock and I'm so thankful for them and each day that I am alive! However, the realization process for me has been hard at times. I feel like I'm dreaming. It was a completely unexpected change of life for me and it still feels surreal that it even happened. Hollys story - conclusion

The Gift of Life is so amazing and we are all true miracles! Im so happy to be alive and so thankful for my donor! I'm really into being a donor advocate and like to share my experience with others. I feel I'm alive to help do as much as I can to promote organ donation. Small Intestine - starts at the pyloric sphincter and ends at the ileocecal sphincter.

First part of small intestine is the duodenum (22 cm). Receives ducts from the liver and pancreas. (The common bile duct) This is where most of the digestion of foods takes place. pH is now above 7 thanks to the secretion of NaHCO3 secreted by the pancreas. Digestive enzymes come from the pancreas. The rest of the small intestine is involved in absorption of nutrients Small Intestine Parts include the

duodenum, jejunum ileum and ileocecal sphincter Duodenum completes digestion of fats,proteins, carbohydrates and nucleic acids The small intestine absorbs fatty acids, amino acids, glucose and minerals. Large Intestine Parts include the cecum (appendix), ascending colon, transverse colon, descending colon, sigmoid colon,

rectum,internal and external anal sphincters Large Intestine The large intestines main functions include the absorption of vitamins, water and minerals Material is moved through by peristalsis NaHCO3 reduces acidity Mucus helps to lubricate the waste Waste is passed at least every 24 hours Large Intestine

Bacteria in the large intestine help to digest certain carbohydrates that the body cannot. (I.e. raffinose) Bacteria will produce waste gases that are passed out as flatus Certain foods (beans, nuts have lots of raffinose

Flexible sigmoidoscopy is a procedure using a small, flexible tube with a fiberoptic camera and light attached to its tip to look into the rectum and the colon. The end of the scope can be bent to pass around corners. Using a sigmoidoscope, a doctor can look into the last two feet of the colon for signs of cancer, polyps, diverticulosis or colitis The American Cancer Society recommends that from age 40 on, individuals should receive an annual rectal exam.

After age 50 individuals should have their stool tested for blood annually and should have a flexible sigmoidoscopy every three to five years. Flexible Sigmoidoscopy Colonoscopy lets the doctor see the lining of your large intestine (rectum and colon).

Using a thin flexible telescope (colonoscope), the doctor can look inside your colon for problems such as swellings, tumors or growths (polyps). The doctor can remove some samples (biopsies) for laboratory analysis. Can treat some lesions (such as polyps) at the same time. Because of the more invasive nature of this procedure the patient is given a general anesthetic. The colon must be empty and clear before the procedure. Colonscopy

Colonscopy images A polyp* is extra tissue that grows inside your body. Colon polyps grow in the large intestine. Most colon polyps are not dangerous. Most are benign, which means they are not

cancer. But over time, some types of polyps can turn into cancer. Usually, polyps that are smaller than a pea aren't harmful. Larger polyps could someday become cancer or may already be cancer. To be safe, doctors remove all polyps and test them Colon polyps This is a small gland under your sternum that is actually a part of lymphatic system Helps to produce white blood cells

It is most active in teenagers and shrinks in adults. Thymus Appendix Blind ending of the large intestine. Has no known functions, perhaps an immune function Appendicitis is most common childhood abdominal operation. Morbid obesity

A disease that seems to have genetic links. Some people gain weight even when they eat a little. One strategy is to restrict the size of the stomach. The other strategy is to restrict the ability of the system to digest and absorb food. Lab-Band procedure In this procedure an inflatable silicone band is placed around the upper part of the stomach to create a small pouch. The outlet from the pouch is restricts the emptying of the food and

thus creates the feeling of fullness Lab-Band surgery before and after pictures Intestinal bypass 1954 - This was the first attempt at surgically induced weight loss. Also referred to as the "J-I bypass," this procedure excluded most of the small intestine from the flow of

food. It was intended to produce malabsorption and was associated with many complications such as severe diarrhea, electrolyte imbalances, kidney stones, and liver failure. This operation is no longer in use. Gastroplasty More commonly known as "stomach stapling." There were many different variations of stomach stapling. The most commonly performed was the "Horizontal Gastroplasty"

which was developed in 1979 at Ohio State University. These types of operations were plagued by failures of the staple lines and have mostly been abandoned. The upper part of the

stomach is divided using an automatic stapling device. This creates the small stomach pouch (approximately the size of a small egg). The small intestine is then divided and re-connected to the remaining small intestine about three feet below the point of division. This connection, called the Roux-en-Y anastamosis, is seen in the diagram to the right. The stomach, duodenum, and several feet of upper small intestine are bypassed.

Roux-en-Y Gastric Bypass

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