THE GASTROINTESTINAL SYSTEM

Rita Daniela Dávila MD

Adapted from Drs. Melvin Braimen, Raymond Lee, CCSF

The Gastrointestinal System

Group of organs involved in the process of digestion

 Extends from the lips of the mouth to the anal canal

 Accessory structures and glands

Gastrointestinal system

Mouth and Salivary Glands

Salivary secretion

 Alpha-amylase begins starch digestion

 Neutralizes oral bacteria acids

 Mucins lubricate food

Diseases of the mouth and salivary glands

 Cavities Aphtous ulcers (canker sores) Herpes simplex Oral Candidiasis (thrush) Oral Cancer Mumps Sjogren’s syndrome Salivary gland tumors

Herpes simplex

Oral candidiasis

PHARYNX

Muscular tube involved in deglutition

Diseases of the pharynx

 Viral pharyngitis

 Streptococcal pharyngitis

 Epiglotitis (croup)

 Peritonsillar abcess

Streptococcal pharyngitis

ESOPHAGUS Muscular tube (10”) that passes food from pharynx into stomach

FUNCTIONS:

 Connects pharynx to stomach

 Peristalsis(contraction of muscles)

Signs and symptoms of esophageal disease

 Heartburn- Due to gastroesophageal reflux

disease

 Dysphagia- Difficulty swallowing

Diseases of the esophagus

 Gastroesophageal Reflux Disease (GERD)

 Achalasia

 Esophageal Cancer (5th most common cause of cancer in adult males)

GERD

Achalasia

Abdomen

STOMACH Located between the esophagus and small intestine

FUNCTIONS:

 Secretes enzymes and acids to aid in food digestion

 Muscular contractions

STOMACH SECRETIONS

Mucus Lubricant, protects surface from acid

Mucous Cells

Intrinsic factor

Vit. B12 absorption Parietal Cells

HCl (Hydrocloric acid)

Kills bacteria, breaks down food, activates pepsinogen

Parietal Cells

Pepsinogen Precursor of pepsin Chief Cells

Gastrin Stimulates acid secretion

G Cells

Signs and symptoms of stomach disease

 Hematemesis (vomiting blood)

-  Commonly due to Peptic ulcer disease

 Melena (dark stools)

- Bleeding proximal to duodenojejunal junction.

Diseases of the stomach

 Hiatal Hernia

 Gastritis

 Peptic Ulcer Disease

 Stomach Cancer

Hiatal hernia

Peptic ulcer disease

Small Intestine

 Small Intestine: 30 feet

 Absorption of most of the nutrients

Large intestine

 Large Intestine: 5 feet Absorbs water from wastes creating stools Stool enters the rectum where nerves create the urge to defecate.

Defecation

-  Rectum fills with fecal material, contracts and internal anal sphincter relaxes.

-  Rectum filled with 25% of capacity, there is urge to defecate.

- When is convenient to defecate, external anal sphincter is relaxed voluntarily.

- Smooth muscle contracts, forcing the feces out of the body.

Signs and symptoms of bowel disease

SMALL BOWEL Colicky pain:

- Pain followed by a pain -free interval

- Symptom of bowel obstruction Diarrhea:

- Infection,malabsorption- If bloody: infarction, volvulus, dysentery  Anemia:

- Malabsorption of iron, folate, vit. B12

LARGE BOWEL Pain:

- Appendicitis, inflammatory bowel disease (IBD), diverticulitis, peritonitis. Diarrhea:

- Infection, laxative abuse. Tenesmus Hematochezia

Small and large bowel disorders

 Inflammatory bowel disease Intestinal Obstruction Appendicitis Diverticulosis/Diverticulitis Irritable Bowel Syndrome Colon Cancer Parasites

Bowel disorders

Diseases of the rectum and anus

 Hemorrhoids

 Anal Fissures

 Perianal abcesses

Liver

 Largest glandular tissue and internal organ of the body. Receives substances via portal vein: metabolites, nutrients, and toxins.  Degrades toxins.  Exocrine and endocrine functions

Gallblader

 Pear-shaped sac (50mL)  Attached to the visceral surface of the liver  Stores the diluted bile, concentrates it and discharges the concentrated bile

Pancreas  Wedge shaped organ.

 Exocrine and endocrine gland

 Exocrine, synthesizes and secretes digestive enzyme precursors

 Endocrine component, dispersed throughout the organ as islets of Langerhans synthesizes insulin and glucagon.

Pancreatic secretion

Alpha Amylase Starch digestion

Lipase Fat digestion

Proteases Protein Digestion

Liver disorders

 Viral Hepatitis Liver abscess Alcoholic hepatitis Cirrhosis Liver tumors

Hepatitis A

 Oral Transmission

 Many patients are asymptomatic.  Disease is very acute. Never chronic.

Hepatitis B

  Infected blood and body fluids (sexual transmission).

  Completely preventable with vaccination

1. Acute disease. Total recovery, and protected from HBV for life.2. Patient unable to develop antibodies.

Chronic hepatitis that can lead to cirrhosis & Liver cancer.

Hepatitis C

 Affects 2% of the population.

 25% develop acute hepatitis, 85% develop chronic hepatitis.

 After 20 years 20% will have cirrhosis

 After 25 years, liver failure and liver cancer

Alcoholic liver disease Alcoholic fatty liver

 Liver fibrosis

 Alcoholic cirrhosis

Liver Cancer

 Malignant cells from cancers elsewhere in the body can lodge in the liver and start a secondary growth (metastatic cancers).  Primary cancers can arise from the

malignant transformation of normal liver cells or from chronic hepatitis.

 The first sign of liver cancer may be jaundice, since the tumor often obstructs the flow of bile.  Liver tumors are evident on ultrasound examination.

Gallblader disorders

 Cholelithiasis

 Cholecystitis

 Gallblader adenocarcinoma

Pancreatic disorders

 Pancreatitis

 Pancreatic cancer

 Diabetes:- Type 1: insulin

dependent- Type 2: non-insulin

dependent

Diagnostic Procedures  Endoscopy

- Colonoscopy and polyp removal- Endoscopy for peptic ulcers  X-Ray contrast studies  Intestinal Biopsy  Liver biopsy  Ultrasound  Stool examination  Lab tests (Bilirrubin, coagulation factors, enzimes, glucose, protein electrophoresis, immune markers)

Signs and Symptoms Abdominal distention Abdominal pain Acholic stools Ascites Bilious vomitus Bloating Bloody stool Bowel sounds Constipation Cramps Eructation

 Fecal impactation Feces Fever Gastrointestinal bleeding Ileus Incontinence Jaundice Malabsorption Nausea Nutrition Tenesmus Vomiting

THANK YOU