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Digestive System

The digestive system is a group of organs working together to convert food into energy and basic nutrients to feed body cells. Food passes through a long tube inside the body known as the alimentary canal or the gastrointestinal tract (GI tract). The alimentary canal is made up of the oral cavity, pharynx, esophagus, stomach, small intestines, and large intestines. In addition to the alimentary canal, there are several important accessory organs that help your body to digest food, but do not have food pass through them. Accessory organs of the digestive system include the teeth, tongue, salivary glands, liver, gallbladder, and pancreas.

Digestive System Parts:

Mouth - Teeth chop food into small pieces, which are moistened by saliva before the tongue and other muscles push the food into the pharynx

Pharynx\Esophagus - The pharynx is responsible for the passing of masses of chewed food from the mouth to the esophagus. The esophagus continuous to carry chewed food along to the stomach.

Stomach – The stomach acts as a storage tank for food. It also contains hydrochloric acid and digestive enzymes that continue the digestion of food that began in the mouth.

Digestive System Parts:

Small Intestine - Made up of the duodenum, jejunum, and ileum. The duodenum is largely responsible for the continuous breaking-down process, with the jejunum and ileum mainly responsible for absorption of nutrients into the bloodstream. The small intestine absorbs about 90% of the nutrients from the food.

Large Intestine - The large intestine absorbs water and contains many symbiotic bacteria that aid in the breaking down of wastes to extract some small amounts of nutrients.

Rectum

Accessory Organs:

Chemical digestion in the small intestine relies on the activities of three accessory digestive organs: the liver, pancreas, and gallbladder The digestive role of the liver is to produce bile and export it to the duodenum. The gallbladder primarily stores, concentrates, and releases bile. The pancreas produces pancreatic juice, which contains digestive enzymes and bicarbonate ions, and delivers it to the duodenum.

Major Functions:

Ingestion of food Secretion of fluids and digestive enzymes Mixing and movement of food and wastes through the

body Digestion of food into smaller pieces Absorption of nutrients Excretion of wastes

Diseases and Disorders of the Digestive System

Diseases and Disorders of the Digestive System

Appendicitis - an inflammation of the appendix Signs and symptoms – lack of appetite, pain in and around the navel

area or in the abdomen, nausea, slight fever, pain in the right leg, and increased white blood cell content

Causes – Blockage in the lining of the appendix with feces or tumor that results in an infection

treatments – Surgery to remove the appendix, Antibiotics to prevent infection

Diseases and Disorders of the Digestive System

cirrhosis - a long lasting liver disease in which normal liver tissue is replaced with nonfunctional scar tissue

Causes – Excessive alcohol consumption, Hepatitis C&B infection and fatty liver

treatments – Liver transplant, Lifestyle changes to stop medications or use of alcohol

According to the National Institutes of Health, cirrhosis is the 12th leading cause of death by disease.

Diseases and Disorders of the Digestive System

Colitis - defined as inflammation of the large intestine (colon).

Causes – caused by viral or bacterial infection or the use of antibiotics. Ulcers in the large intestine, Crohn’s disease, various other diseases, and stress may contribute

Symptoms – Belly pain or cramps, diarrhea, bleeding from the rectum

treatments – Treating underlying causes, changing antibiotics, repair of ulcers

Some people find that certain foods make their symptoms worse.

Diseases and Disorders of the Digestive System

Heartburn - called gastroesophageal reflux disease (GERD) - occurs when stomach acids are pushed into the esophagus this create a burning discomfort in the upper abdomen or below the breast bone.

Causes – alcohol, some foods high in fat and oils, defective esophageal sphincter, pregnancy, obesity, hiatal hernia, and repeated vomiting.

treatments – Not lying down after meal Reducing weight Diet changes Reduce alcohol consumption Medications

Heartburn is a weekly occurrence for up to 20% of a population and is very common in pregnant women.

Diseases and Disorders of the Digestive System

Hepatitis - inflammation of the liver. Causes –it may be caused by drugs, alcohol use, or

certain medical conditions. But in most cases, it’s caused by a virus this is known as viral hepatitis, A, B, and C.

treatments – Bed rest, abstaining from alcohol, and taking medication to help relieve symptoms. Most people who have hepatitis A and E get well on their own after a few weeks.

Hepatitis B is treated with drugs, such as lamivudine and adefovir dipivoxil. Hepatitis C is treated with a combination of peginterferon and ribovarin.

Liver transplant of hepatitis B or C, or D-caused liver failure.

Bacterial Diseases of the Upper Digestive Tract (Mouth & Stomach)

Tooth Decay (dental caries): Causative agent – Streptococcus mutans and sucrose

A) Most common infectious disease of humans B) Young are more susceptible than old

Periodontal Disease: A) Hundreds of bacterial species are involved but the most likely cause is Porphyromonas gingivalisB) Chronic inflammation of the gums (gingivitis) and tissues around the roots of the teeth (periodontitis)C) Primarily a disease of persons 35+

Quiz! 1.Stores the liver's digestive juices until they are needed by the intestines? Pancreas

2.The job of the digestive system? To take in and break down food for use by the body

3.An organ that produces a bodily juice called bile? Gallbladder

4.A long tube that carries food from the mouth to the stomach? Esophagus

5.This part of the digestive system removes solid wastes such as feces from the body? Large Intestine

‘’A healthy outside starts from the inside’’

Shatha Al-MahmoudShaima Alhaidary