Digestive System

Lecture Goals

• Name the organs of the digesve system and describe their locaons and funcons. • Deﬁne combining forms for organs and know the meaning of related terminology. • Describe signs, symptoms, and disease condions aﬀecng the digesve system.

Lecture Goals

• Deﬁne new suﬃxes and use them with digesve system combining forms. • List and explain laboratory tests, clinical procedures, and abbreviaons common to the digesve system. • Apply your new knowledge to understanding medical terms in their proper context, such as medical reports and records.

1 Introducon

The digesve or gastrointesnal system performs four main funcons: • ingeson • digeson • absorpon • eliminaon

Introducon: Ingeson and Digeson • Ingeson—food material taken into mouth

• Digeson—food is broken down, mechanically and chemically, as it travels through the gastrointesnal tract. Ø Digesve enzymes aid the breakdown of complex nutrients. • Proteins → amino acids • Sugars → glucose • Fats → fay acids or triglycerides

Introducon: Absorpon

• Digested food passes into the bloodstream through lining cells of the small intesne. • Nutrients travel to all cells of the body. • Cells burn nutrients to release the energy stored in food.

2 Introducon: Eliminaon

• The body eliminates solid waste materials that cannot be absorbed into bloodstream. • The large intesne concentrates feces. • The wastes pass out of the body through the anus.

Organs of the Digesve System

• The gastrointesnal tract begins with the oral cavity.

Oral Cavity

Major parts of the oral cavity

3 Oral Cavity (cont’d)

Major parts of the oral cavity

Oral Cavity (cont’d)

Upper permanent teeth within the dental arch

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Oral Cavity (cont’d)

Upper permanent teeth within the dental arch

4 Oral Cavity (cont’d)

Anatomy of a tooth

Oral Cavity (cont’d)

Anatomy of a tooth

Oral Cavity (cont’d)

Salivary glands

5 Pharynx

Degluon

Pharynx (cont’d)

Degluon

The Digesve Tract

6 The Digesve Tract (cont’d)

Esophagus/Stomach

Parts of the stomach

Esophagus/Stomach (cont’d)

Parts of the stomach

7 Small Intesne

Villi in the lining of the small intesne

Large Intesne

Parts of the large intesne

Large Intesne (cont’d)

Parts of the large intesne

8 Liver, Gallbladder, and Pancreas

Parts of the liver, gallbladder, and pancreas

Liver, Gallbladder, and Pancreas (cont’d) Parts of the liver, gallbladder, and pancreas

Liver, Gallbladder, and Pancreas (cont’d)

Besides producing bile, the liver: • Helps maintain normal blood glucose levels • Manufactures blood proteins necessary for clong • Releases bilirubin, a pigment in bile • Removes toxins and poisons from the blood

9 Liver, Gallbladder, and Pancreas

The pancreas and its funcons

Food Pathway through the GI Tract

Food enters through the oral cavity and exits through the anus

Food Pathway through the GI Tract (cont’d) Food enters through the oral cavity and exits through the anus

10 QUICK QUIZ:

1. What happens if bilirubin cannot leave the body and remains in the bloodstream? A. Gluconeogenesis B. Emulsiﬁcaon C. Hyperbilirubinemia D. Glycogenolysis

QUICK QUIZ:

2. Which term is the ﬁrst part of the large intesne? A. Cecum B. Duodenum C. Jejunum D. Pylorus

QUICK QUIZ: (cont’d)

3. Which term means swallowing? A. Mascaon B. Degluon C. Emulsiﬁcaon D. Peristalsis

11 QUICK QUIZ:

4. Which term means inﬂammaon of the lip? A. Cholecyss B. Celiac C. Appendicis D. Cheilis

Pathology of the Digesve System Signs and symptoms • Anorexia – lack of appete • Ascites – abnormal accumulaon of fluid in the abdomen • Borborygmus (plural: borborygmi) – rumbling or gurgling noise produced by the movement of gas, fluid, or both in the GI tract • Conspaon – difficulty in passing stools • Diarrhea – frequent passage of loose, watery stools

Pathology of the Digesve System (cont’d) • Dysphagia – diﬃculty in swallowing • Eructaon – gas expelled from the stomach through the mouth • Flatus – gas expelled through the anus • Hematochezia – passage of fresh, bright red blood from the rectum • Jaundice (icterus) – yellow-orange coloraon of the skin and whites of the eyes caused by high levels of bilirubin in the blood

12 Pathology of the Digesve System (cont’d) • Melena – black, tarry stools; feces containing digested blood • Nausea – unpleasant sensaon in the stomach associated with a tendency to vomit • Steatorrhea – fat in the feces; frothy, foul- smelling fecal maer

Pathologic Condions Oral Cavity and Teeth

• Aphthous stomas – inﬂammaon of the mouth with small, painful ulcers

• Dental caries – tooth decay • Herpec stomas – inﬂammaon of the mouth by infecon with the herpes virus

• Oral leukoplakia – white plaques or patches

• Periodontal disease – inﬂammaon and degeneraon of the gums, teeth and surrounding bone

Pathologic Condions Oral Cavity and Teeth

13 Pathologic Condions Upper Gastrointesnal Tract

• Achalasia – failure of the lower esophagus sphincter (LES) muscle to relax

Pathologic Condions Upper Gastrointesnal Tract • Esophageal cancer – malignant tumor of the esophagus

• Esophageal varices – swollen, varicose veins at the lower end of the esophagus

• Gastric carcinoma – malignant tumor of the stomach

Pathologic Condions Upper Gastrointesnal Tract

14 Pathologic Condions Upper Gastrointesnal Tract (cont’d)

• Gastroesophageal reﬂux disease (GERD) – solids and ﬂuids return to the mouth from the stomach

• Pepc ulcer – open sore or lesion of the mucous membrane of the stomach or duodenum

Pathologic Condions Upper Gastrointesnal Tract (cont’d) • Hernia – protrusion of an organ or part through the muscle normally containing it

Pathologic Condions Lower Gastrointesnal Tract Small and Large Intesnes

• Anal ﬁstula – abnormal tube-like passageway near the anus

• Colonic polyposis – polyps protrude from the mucous membrane of the colon

15 Pathologic Condions Lower Gastrointesnal Tract Small and Large Intesnes

• Anal ﬁstula – abnormal tube-like passageway near the anus

• Colonic polyposis – polyps protrude from the mucous membrane of the colon

Pathologic Condions Lower Gastrointesnal Tract Small and Large Intesnes (cont’d)

• Colorectal cancer – adenocarcinoma of the colon or rectum or both

Pathologic Condions Lower Gastrointesnal Tract Small and Large Intesnes (cont’d)

• Crohn disease – chronic inﬂammaon of the intesnal tract • Diverculosis – abnormal side pockets (outpouchings) in the intesnal wall

16 Pathologic Condions Lower Gastrointesnal Tract Small and Large Intesnes (cont’d)

• Dysentery – painful, inflamed intesnes • Hemorrhoids – swollen, twisted, varicose veins in the rectal region • Ileus – failure of peristalsis with resulng obstrucon of the intesnes • Inflammatory bowel disease (IBD) – inflammaon of the colon and small intesne

Pathologic Condions Lower Gastrointesnal Tract Small and Large Intesnes (cont’d) • Intussuscepon – telescoping of the intesnes

• Volvulus – twisng of the intesnes on

Pathologic Condions Lower Gastrointesnal Tract Small and Large Intesnes (cont’d) • Intussuscepon – telescoping of the intesnes • IBS – irritable bowel syndrome – group of gastrointesnal symptoms associated with stress and tension • Ulcerave colis – chronic inﬂammaon of the colon with the presence of ulcers • Volvulus – twisng of the intesnes on itself

17 Pathologic Condions Liver, Gallbladder, and Pancreas • Cholelithiasis – gallstones in the gallbladder • Cirrhosis – chronic degenerave disease of the liver • Pancreac cancer – malignant tumor of the pancreas • Pancreas – inﬂammaon of the pancreas • Viral hepas – inﬂammaon of the liver caused by a virus

Pathologic Condions Liver Gallbladder, and Pancreas (cont’d)

• Cholelithiasis – gallstones in the gallbladder

Laboratory Tests and Clinical Procedures • Laboratory tests Ø Liver funcon tests (LFTs): tests for enzymes and bilirubin in blood Ø Stool culture: test for microorganisms in stool Ø Stool guaiac test or Hemoccult test: test to detect blood in feces

18 Laboratory Tests and Clinical Procedures • Clinical procedures Ø X-rays • Lower gastrointesnal series (barium enema) • Upper gastrointesnal series • Cholangiography • Computed tomography (CT scan)

19 Laboratory Tests and Clinical Procedures (cont’d) • Clinical procedures

Ø Ultrasound examinaon • Abdominal ultrasonography • Endoscopic ultrasonography (EUS)

Ø Magnec resonance techniques • Magnec resonance imaging (MRI)

Ø Nuclear medicine test • Hepatobiliary iminodiacec acid scan (HIDA scan)

Laboratory Tests and Clinical Procedures (cont’d) • Other procedures Ø Gastric bypass or bariatric surgery: reduces stomach size Ø Gastrointesnal endoscopy: visual examinaon of the GI tract Ø Laparoscopy: visual examinaon of the abdomen Ø Liver biopsy: removal of liver ssue for microscopic examinaon Ø Nasogastric intubaon: inseron of a tube through the nose into the stomach Ø Paracentesis (abdominocentesis): puncture to remove ﬂuid from abdomen

QUICK QUIZ:

1. Which term means diﬃculty in swallowing? A. Dysphasia B. Dysphagia C. Dysplasia D. Polyphagia

21 QUICK QUIZ: (cont’d)

2. Which term means to control or stop bleeding? A. Hemostasis B. Hematoma C. Hemoptysis D. Cholestasis

QUICK QUIZ:

3. Which term means enlarged liver? A. Acromegaly B. Cardiomegaly C. Hepatomegaly D. Hepas

QUICK QUIZ:

4. Which of the following tests for the clear ﬂuid that remains aer blood has cloed (serum)? A. Stool guaiac B. Hemoccult C. Stool culture D. LFTs

22 QUICK QUIZ:

5. Which procedure is a surgical puncture to remove ﬂuid from the abdomen? A. Laparoscopy B. Laparotomy C. Abdominectomy D. Abdominocentesis

Cauon!

• Pay aenon to spelling! – Ileum vs ilium – Chol/e vs col/o – Cholescyst/o vs cyst/o • Don’t confuse IBS and IBD