2.08 Understand the functions and disorders of the digestive system Essential questions What are the functions of the digestive system? How do the functions

2.08 Understand the functions and disorders of the digestive system

2.08 Understand the functions and disorders of the digestive

systemEssential questions

What are the functions of the digestive system? How do the functions of chemical and physical digestion

interrelate? What are the common disorders of the digestive system? How are disorders of the digestive system treated? How do you relate the body’s use of nutrients to the

digestive system?

2.08 Understand the functions and disorders of the digestive system 2

Understand the functions of the

digestive system


Functions of the digestive system

Mouth (buccal cavity) What digestive system functions occur in the

mouth?



TongueWhat is the digestive system function of the tongue?

The tongue consists of four types of taste buds and is a very maneuverable and pliable muscle. It shifts food around in the mouth in order to assist with swallowing.

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TeethWhat is the digestive system function of the teeth?

mastication -chewing, tearing, or grinding food with the teeth while it becomes mixed with saliva.



How is the tooth’s shape related to its function? Incisors- 8 teeth in the front and center of your

mouth. You use these teeth to take bites of your food.

Cupids- The 4 canine teeth are very strong, pointed corner teeth for tearing and shredding. They are larger and stronger than the incisors.

Bicuspids - The 8 premolars are used for chewing and grinding food

Molars - The 12 molars are the back human teeth, also used for chewing and grinding food.


Salivary glands What is the digestive

system function of the salivary glands?

The function of the salivary glands is to make saliva and help the bolus (soft mass of chewed food) go down the esophagus easily.

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What are the functions of these oral cavity structures?

Palate- the roof of the mouth separating the mouth from the nasal cavity

Uvula -is a conic projection from the posterior edge of the middle of the soft palate.

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PharynxWhat is the function of the pharynx?

The pharynx is the part of the throat that lies between the mouth and the larynx.

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Esophagus What does the esophagus do?

The esophagus is the tube that carries food, liquids and saliva from your mouth to the stomach.

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Stomach What are the

functions of the stomach?

What chemicals are released there?

How long does it take for the stomach to empty?


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What are the are the functions of the stomach? What are the What are the functions of the stomach?functions of the stomach?What are the functions of the stomach?

ns of the stomach?

The stomach is a muscular organ located on the left side of the upper abdomen. The stomach receives food from the esophagus.


The stomach secretes acid and enzymes that digest food. Ridges of muscle tissue called rugae line the stomach.




The stomach is famous for its secretion of acid, but acid is only one of four major products secreted by the gastric epithelium. Chemicals in the stomach like pepsin, rennin, and lipase interact to break down the food.

Digestion time varies depending on the individual. For most healthy adults, it's usually between 24 and 72 hours. After you eat, it takes about six to eight hours for food to pass through your stomach and small intestine. Food then enters your large intestine (colon) for further digestion and absorption of water. Elimination of undigested food residue through the large intestine usually begins after a total of 24 hours. Complete elimination from the body may take several days.



Small IntestineYour small intestine is the longest part of your

digestive system - about twenty feet long! It connects your stomach to your large intestine (or colon) and folds many times to fit inside your abdomen. Your small intestine does most of the digesting of the foods you eat. It has three areas called the duodenum, the ileum, and the jejunum.


Mechanical digestion - mixes the chyme with enzymes from the small intestine and pancreas. Peristalsis moves the chyme through the small intestine.

Chemical digestion. Enzymes from the small intestine and pancreas break down all four groups of molecules found in food; polysaccharides, proteins, fats, and nucleic acids.

Absorption. The small intestine is the primary location in the GI tract for absorption of nutrients.


The duodenum, 10 inches long, receives chyme from the stomach through the pyloric sphincter. Ducts that empty into the duodenum deliver pancreatic juice and bile from the pancreas and liver.

The jejunum, about 8 feet long, is the middle section of the small intestine.

The ileum, about 12 feet long, is the last section of the small intestine. It ends with the ileocecal valve (sphincter), which regulates the movement of chyme into the large intestine and prevents backward movement of material from the large intestine.


Pancreas What digestive enzymes

are secreted by the pancreas?

What is there function?


Which other system

does the pancreas function?

The pancreas is an organ in the digestive and endocrine system. It is both an endocrine gland producing several important hormones, including insulin. It also functions as an exocrine gland, secreting pancreatic juice containing digestive enzymes that pass to the small intestine. These enzymes help in the further breakdown of carbohydrates, protein, and fat in the chyme.


Liver What are the functions of

the liver?

What is the function of bile glycogen?

What vitamin is produced by the liver? Why is it important?


The liver is located in the upper right-hand portion of the abdominal cavity, beneath the diaphragm, and on top of the stomach, right kidney, and intestines. Shaped like a cone, the liver is a dark reddish-brown organ that weighs about 3 pounds.

The liver regulates most chemical levels in the blood and excretes a product called bile, which helps carry away waste products from the liver. All the blood leaving the stomach and intestines passes through the liver. More than 500 vital functions have been identified with the liver.

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A few functions of the liver: Conversion of excess glucose into glycogen for

storage (glycogen can later be converted back to glucose for energy)

Processing of hemoglobin for use of its iron content (the liver stores iron)

Clearing the blood of drugs and other poisonous substances

Regulating blood clotting Resisting infections by producing immune

factors and removing bacteria from the bloodstream


GallbladderLocated just below the liver.

What is the function of the gallbladder?

the gallbladder's main function is to store bile, which helps the body break down and digest fats. In response to signals, the gallbladder squeezes stored bile into the small intestine through a series of tubes called ducts. Bile helps digest fats, but the gallbladder itself is not essential. Removing the gallbladder in an otherwise healthy individual typically causes no observable problems with health or digestion yet there may be a small risk of diarrhea and fat malabsorption.


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Large intestine What are the functions of the

large intestines?

What is its relevance to health?

What type of diet promotes colon health?


What is the semi-solid liquid secreted

from the ileum through the ileoceccal valve

called that enters the large intestine?

The large intestine is the portion of the digestive system most responsible for absorption of water from the indigestible residue of food. Material passes through the ascending, transverse, descending and sigmoid portions of the colon, and finally into the rectum. From the rectum, the waste is expelled from the body.


Fecal transplant Allows the bacteria from the healthy stool to repopulate the

gut of the patient who has lost healthy bacteria in their gut


Used to treat Clostridium difficile that grows in human intestines Symptoms range from

persistent diarrhea to life-threatening inflammation of the colon to death


What can healthcare professionals learn from observing stool specimens?

On average, how much flatus does a person produce per day?


Act of Digestion

Define these terms:

Ingestion

Mastication

Digestion

Secretion

Absorption

Excretion


Disorders of the digestive system

Anorexia Decreased or poor

appetite

Symptom

Anorexia nervosa Eating disorder

characterized by refusal to eat

Psychiatric disorder

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VS

http://www.anairhoads.org/graphics/anorexia.jpg


Caries What is another name for

caries? Dental caries, otherwise

known as tooth decay, is one of the most prevalent chronic diseases of people worldwide; individuals are susceptible to this disease throughout their lifetime.

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Can you identify

preventive measures?

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Cholecystitis What is cholecystitis?

What are the symptoms?

How is it treated?

Cholelithiasis


Acute cholecystitis is a sudden inflammation of the gallbladder that causes severe abdominal pain. In 90% of cases, acute cholecystitis is caused by gallstones in the gallbladder.

The main symptom is pain in the upper right side or upper middle of the abdomen. The pain may:

Be sharp, cramping, or dull Be steady Spread to the back or below the right

shoulder blade2.08 Understand the functions and disorders of the digestive system 35

In the emergency room, patients with acute cholecystitis are given fluids through a vein and antibiotics to fight infection.

Although cholecystitis may clear up on its own, surgery to remove the gallbladder cholecystectomy is usually needed when gallstones are present.

Nonsurgical treatment includes: Antibiotics to fight infection Low-fat diet (when food can be tolerated) Pain medicines



Cleft palate What is cleft palate? What is its impact on

health? Who have this

condition?


What specialist(s) should be

consulted to correct a cleft palates?

Cleft lip and cleft palate are birth defects that affect the upper lip and roof of the mouth. They happen when the tissue that forms the roof of the mouth and upper lip don't join before birth.

The problem can range from a small notch in the lip to a groove that runs into the roof of the mouth and nose


Treatment - surgery to close the lip and palate. Doctors often do this surgery in several stages.

Usually the first surgery is during the baby's first year. With treatment, most children with cleft lip or palate do well.



Cirrhosis What is cirrhosis? Cirrhosis (sih-ROW-sis) is

scarring of the liver.

What are the symptoms?

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Cirrhosis can be caused by a number of conditions, including long-standing inflammation, poisons, infections, and heart disease, as well as chronic alcoholism and chronic hepatitis.

Treatment for cirrhosis cannot reverse liver damage, but it can stop or slow progression of the disease and reduce complications. Treatment depends on what is causing the cirrhosis and which particular complications, if any, have appeared.



Constipation What is constipation? Constipation is infrequent bowel

movements or difficult passage of stools. What's considered normal frequency for bowel movements varies widely.

In general, however, you're probably experiencing constipation if you pass fewer than three stools a week, and your stools are hard and dry.

How can constipation

be prevented?

What is obstipation?

Severe constipation- the colon is never truly emptied.


Disorders of the digestive disorders

Diarrhea Diarrhea describes

bowel movements (stools) that are loose and watery. It is very common and usually not serious. Many people will have diarrhea once or twice each year.

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The most common cause of diarrhea is a virus that infects the gut. The infection usually lasts for two days and is sometimes called "intestinal flu" or "stomach flu." Diarrhea may also be caused by:

Infection by bacteria Eating foods that upset the digestive system Allergies to certain foods Medications Diseases of the intestines -Crohn's disease, and

ulcerative colitis Diabetes

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Disorders of the digestive disorders

Gastroenteritis Gastroenteritis is an inflammation of your

stomach and intestines. Common causes are: Viruses. Food or water contaminated by bacteria or

parasites. Reaction to a new food. Side effect from medications.2.08 Understand the functions and

disorders of the digestive system


Gastroesophageal reflux disease (GERD)

What are some common causes of GERD?


Gastroesophageal reflux disease (GERD) is a condition in which the stomach contents leak backwards from the stomach into the esophagus. This action can irritate the esophagus, causing heartburn and other symptoms.

The risk factors for reflux include:

Alcohol Hiatal hernia (a

condition in which part of the stomach moves above the diaphragm

Obesity Pregnancy Scleroderma Smoking



Hepatitis Acute Chronic

Hepatitis A, B, C, D, E

What are some common symptoms of hepatitis?


The word hepatitis means an inflammation of the liver. It can be caused by one of many things — including a bacterial infection, liver injury caused by a toxin (poison), and even an attack on the liver by the body's own immune system. However, the condition is usually caused by a virus. The three most common hepatitis viruses are hepatitis A, hepatitis B, or hepatitis C. Two other types of hepatitis virus, D and E, are rare in the United States


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Some people who have hepatitis have no symptoms. Others may have:

Loss of appetiteNausea and vomitingDiarrheaDark-colored urine and pale bowel movementsStomach painJaundice, yellowing of skin and eyes

Treatments for hepatitis Hepatitis A - There is no treatment specifically

for hepatitis A. The vast majority of patients with Hepatitis A will recover spontaneously.

Hepatitis B - needs to rest. He will require a diet that is high in protein and carbohydrate - this is to repair damaged liver cells, as well as to protect the liver.

Hepatitis C - A patient with Hepatitis C will be prescribed interferon

Hepatitis D or E - So far, there is no effective treatment for either Hepatitis D or E.



Irritable bowel syndrome

Define irritable bowel syndrome.

Discuss how will treatments relate to: Lifestyle Diet Medication


Irritable bowel syndrome (IBS) is a disorder that leads to abdominal pain and cramping, changes in bowel movements, and other symptoms.

IBS is not the same as inflammatory bowel disease (IBD), which includes Crohn‘s disease and ulcerative colitis. In IBS, the structure of the bowel is not abnormal.


http://www.ncbi.nlm.nih.gov/pubmedhealth/n/pmh_adam/A000249/



The intestine is connected to the brain. Signals go back and forth between the bowel and brain. These signals affect bowel function and symptoms. The nerves can become more active during stress, causing the intestines to be more sensitive and squeeze (contract) more.

IBS can occur at any age, but it often begins in the teen years or early adulthood. It is twice as common in women as in men.

About 1 in 6 people in the U.S. have symptoms of IBS. It is the most common intestinal problem that causes patients to be referred to a bowel specialist (gastroenterologist).


The goal of treatment is to relieve symptoms. Lifestyle changes can help in some cases of

IBS. Regular exercise and improved sleep habits may reduce anxiety and help relieve bowel symptoms.

No specific diet can be recommended for IBS, because the condition differs from one person to another.

Avoid foods and drinks that stimulate the intestines (such as caffeine, tea, or colas)

Avoid large meals Increase fiber in the diet (this may improve

constipation but make bloating worse) 56


Peptic ulcer What is a peptic ulcer?

What causes it?

How is it treated?


An ulcer is a sore, which means it's an open, painful wound. Peptic ulcers are ulcers that form in the stomach or the upper part of the small intestine, called the duodenum. An ulcer in the stomach is called a gastric ulcer and an ulcer in the duodenum is called a duodenal ulcer.

Ulcer result when H. pylori or a drug weakens the protective mucous coating of the stomach and duodenum, allowing acid to get through to the sensitive lining beneath. Both the acid and the bacteria can irritate the lining and cause an ulcer to form.


H. pylori infection is usually contracted in childhood, perhaps through food, water, or close contact with an infected individual. Infections are more common in adults older than age 60 and in developing countries.

And most people with H. pylori don't display any symptoms until they're older. In fact, they may go through life unaware that they're infected.


An ulcer may or may not have symptoms. When symptoms occur, they may include:

A gnawing or burning pain in the middle or upper stomach between meals or at night

Bloating Heartburn Nausea or vomiting


Relevance of nutrition to the

digestive system

Healthy dietary habits help maintain homeostasis of body systems


To treat an ulcer, first eliminate substances that can be causing the ulcers. If you smoke or drink alcohol, stop. If the ulcer is believed to be caused by the use of NSAIDs, they need to be stopped.


Antibiotics. If you have H. pylori infection, then antibiotics are used. There are multiple combinations of antibiotics that are taken for one to two weeks along with a PPI. Pepto-Bismol is also part of some treatment regimens.

Upper endoscopy . Some bleeding ulcers can be treated through an endoscope.

Surgery. Sometimes an operation is needed if the ulcer has created a hole in the wall of the stomach or if there is serious bleeding that can't be controlled


Relevance of nutrition to the digestive system

Vitamins Fat soluble

Vitamins A, D, E, K Water soluble

Vitamins C, B

Electrolytes Calcium Chloride Magnesium Phosphorus Potassium Sodium


2.08 Understand the functions and disorders of the digestive

systemEssential questions

What are the functions of the digestive system? How do the functions of chemical and physical digestion

interrelate? What are the common disorders of the digestive system? How are disorders of the digestive system treated? How do you relate the body’s use of nutrients to the

digestive system?


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2.08 Understand the functions and disorders of the digestive system Essential questions What are the functions of the digestive system? How do the functions