overview of the digestive system and disorders (disease) of it.
King Saud University, college of applied medical sciences, CLS 224
Anatomy and physiology
Shatha Almahmoud
2. 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.
3. 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
PharynxEsophagus - 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.
4. 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
5. 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.
6. 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
8. 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
9. 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.
10. 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.
11. 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.
12. 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.
13. 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 gingivalis
B) Chronic inflammation of the gums (gingivitis) and tissues around the
roots of the teeth (periodontitis)
C) Primarily a disease of persons 35+
14. 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
