DIGESTIVE SYSTEM

THE MOUTH The initial place of digestion, teeth begin to break down food into small pieces so the digestive enzymes can break food up more efficiently Teeth –Incisors Bite food with sharp edge Bite into softer foods –Canines Tears dense food Punctures food –Bicuspids and Molars Crush and grind food before swallowed –Tongue Brings food into contact with teeth Helps to swallow food –Parotid Secretes ptyalin Breaks carbohydrates down into simple sugars –Submandibular Provides moisture and taste buds Aids in the sensation of salty, sweet, bitter, and sour –Sublingual Secretes ptyalin Breaks carbohydrates down into simple sugars

THE ESOPHAGUS Second step in digestion, where food is moved from mouth to stomach to be broken down into simple form so body can absorb and use it –Bolus Mashed up food that is swallowed The soft palate closes nasal cavity and the epiglottis cover the larynx –Inner Layer Forms circles around epiglottis –Outer Layer Run longitudinally Approximately 10 inches in length

THE STOMACH The place where the food is broken up into the simplest form Cardiac sphincter –Opening into the stomach from esophagus Dilates as the peristaltic approaches –One way gate into the stomach Closes after the entry of food so nothing escapes 3 layers –Inner Thick and full of rugaes (folds) Capable of expanding to hold up to a half gallon of food or liquid –Circular Works with the oblique layer to break down food into tiny particles The process will take longer if the good is poorly chewed –Oblique Works with the circular layer to break down food into tiny particles The process will take longer if food is poorly chewed

THE SMALL INTESTINE The narrow, winding, upper part of the intestine where digestion is completed and nutrients are absorbed by the blood. It extends from the pylorus to the cecum and consists of the duodenum, the jejunum, and the ileum. Liver –Bile Aid in the digestion of fats Secretes a pint a day Gallbladder is the concentration and storage area Glycogen –Stored in liver –Form of glucose from a carbohydrate Pancreas –Secretion method Exocrine, through ducts Endocrine, directly into blood stream –Secreted chemicals Pancreatic juice, reacts with all three nutrients (carbohydrates, proteins, glucose) Insulin- allows sugar to enter the body’s cells

THE LARGE INTESTINE The waste products, any indigestible material, and the excess water is sent to the large intestine through the ileocecal valve The large intestine is 5 feet long, and 2 inches in diameter It is also known as the colon –Cecum Small pouch- like section of the colon, with the appendix attached to it. –Rectum The collecting area for the remains of digestion. When enough material is accumulated, sensors are activated and the urge to defecate is felt. It’s 6 – 8 inches long –Anal canal A narrow passageway about 1 inch long, extending for the rectum to the anus. The large intestine is divided into 4 sections –Ascending section of colon- joins cecum at ileocecal valve and continues upward. –Transverse section of colon- begins at the hepatic flexure and extends in a loop across the abdominal cavity to a point below the spleen, the splenic flexure. –Descending section of colon- begins at the splenic flexure and extends downward along the left side of the abdomen until it reaches the edge of the pelvic cavity –Sigmoid section of colon- S-shaped section of the long intestine within the pelvic cavity. It extends from the left iliac crest, over and back, to join the rectum

DIAGNOSTIC EXAMS Cholecystography –X-Ray exam of the gallbladder following oral administration of a contrast medium Gastrointestinal Series (X-Rays) –Radiological studies of the GI tract Colonoscopy –Exam to view the entire large intestine using a flexible fiberoptic scope Gastroscopy –Viewing of the esophagus, stomach and upper duodenum through a flexible scope that is lighted by fiberoptics Nuclear Medicine Study –Scanning of structures such as the spleen or liver, made visible by radioactive materials Occult Blood Test –A stool sample is examined to look for blood. This diagnosis bleeding within the intestinal tract Proctoscopy –Exam of the lower rectum and anal canal through a 3 inch long protoscope Sigmoidoscopy –An exam to view the lower portion of the sigmoid and rectum through a inch long protoscope Ultrasound –Uses high frequency sound waves in order to view the liver, gallbladder, or pancreas

DISEASES OR DISORDERS Anorectal abscess and Fistula- localized infection due to a collection of exudated in the soft tissue adjacent to the anus or rectum Appendicitis- an acute inflammation of the appendix, usually caused by an obstruction to the intestinal lumen Cirrhosis- chronic disease of the liver, which causes destruction of liver cells. This leads to impaired blood and lymph and interferes with the life preserving functions of the liver Colitis- inflammation of the colon Colorectal Cancer- malignancy of the colon of rectum. The 3 rd most common cancer in men and women Colostomy- artificial opening of the colon, allows fecal material to be excreted from the body through the abdominal wall Constipation- sluggish bowel action characterized by dry and infrequent bowel movements Chron’s- inflammation of any portion of the GI tract, most common terminal ileum Diarrhea- condition of repeated passage of unformed wastes Diverticulosis- presence of bulging pouches in the wall of the GI tract where the lining has been pushed into the surrounding muscle Esophageal Varices- dilated, tortuous veins in the lower section of the esophagus Fissure of the anus- where there is a crack or tear in the lining of the anus

FOUR PHASES OF THE DIGESTIVE PROCESS Ingestion : is the consumption of a substance by an organism. In animals, it normally is accomplished by taking in the substance through the mouth into the gastrointestinal tract, such as through eating or drinking. Digestion : is the process by which the body breaks down food into smaller components that can be absorbed by the blood stream. Absorption : the process of absorbing or of being absorbed Elimination : the act of discharging or excreting waste products or foreign substances from the body, bodily discharges including urine, feces, and vomit