Untitled Quiz

Learning Outcomes

• Students will be able to describe the structure and function of the gastrointestinal (GI) tract organs.
• Students will be able to explain mechanical and chemical processes involved in digesting and absorbing nutrients and eliminating waste products.
• Students will be able to distinguish between normal and abnormal GI system assessment findings.
• Students will be able to recognize and evaluate major gastrointestinal dysfunction symptoms using health history and physical assessment findings.
• Students will be able to identify diagnostic tests used to assess GI tract function and related nursing implications.

Anatomic and Physiologic Overview

• The GI tract extends from the mouth to the anus.
• Organs include: oral cavity, pharynx, esophagus, stomach, liver, gallbladder, duodenum, pancreas, small intestine, large intestine, rectum, and anus.
• The esophagus is located in the mediastinum, anterior to the spine.

Anatomy of the Gastrointestinal System: Stomach

• The stomach is located in the left upper abdomen, under the left lobe of the liver, and over the pancreas.
• Its capacity is roughly 1500 mL.
• Functions include storing food, secreting digestive fluids, and propelling partially digested food into the small intestine.
• The stomach has four anatomic regions: cardia, fundus, body, and pylorus.
• The gastroesophageal junction is the inlet to the stomach.

Anatomy of the Gastrointestinal System: Small Intestine

• The small intestine is the longest part of the GI tract, measuring approximately 70 meters.
• Its surface area is important for secretion and absorption.
• Three sections: duodenum (proximal), jejunum (middle), and ileum (distal).
• The ileum terminates at the ileocecal valve.
• The vermiform appendix is attached to the cecum.

Anatomy of the Gastrointestinal System: Large Intestine

• The large intestine consists of an ascending, transverse, and descending segment.
• It includes the sigmoid colon, rectum, and anus.
• The anus has both internal and external anal sphincters, regulating the anal outlet.
• The portal venous system is composed of five large veins (superior mesenteric, inferior mesenteric, gastric, splenic, and cystic) that eventually form the vena portae, which enters the liver.
• Blood flow to the GI tract is approximately 20% of the total cardiac output and increases significantly after eating.

Function of the Digestive System

• Major functions include breaking down food into molecules for digestion, absorbing nutrients into the bloodstream, and eliminating undigested waste products.
• The parasympathetic and sympathetic nervous systems innervate the GI tract.

Process of Digestion: Chewing

• Food is broken into smaller pieces for enzyme mixing and easier swallowing.
• Approximately 1.5 liters of saliva are secreted daily by parotid, submaxillary, and sublingual glands.
• Saliva contains ptyalin (salivary amylase) which starts digesting starches.

Process of Digestion: Swallowing

• The voluntary act is regulated by the swallowing center in the medulla oblongata of the central nervous system (CNS).
• The lower esophageal sphincter prevents stomach contents from refluxing into the esophagus.

Process of Digestion: Gastric Function

• Gastric secretions (totaling 2.4 liters/day) can have a pH as low as 1. Hydrochloric acid (HCl) contributes to the acidity.
• Gastric secretion is important for breaking down food into absorbable components, and for destroying bacteria.
• Pepsin (a protein-digesting enzyme) is produced by chief cells.
• Intrinsic factor assists with vitamin B12 absorption in the ileum.

Process of Digestion: Large Intestine Function

• Within 4 hours of eating, waste material enters the large intestine, with bacteria assisting in waste breakdown.
• Key function: absorbing water and electrolytes.
• Waste products are 75% fluid, 25% solids, and include undigested food, inorganic material, water, and bacteria.
• Stool color results from bile breakdown by intestinal bacteria.

Process of Digestion: Small Intestine Function

• Duodenal secretions come from accessory glands (pancreas, liver, and gallbladder) as well as glands in the intestine wall itself.
• Secretions include digestive enzymes (amylase, lipase, and bile).
• Pancreatic secretions are alkaline due to high bicarbonate content.
• Enzymes like trypsin, amylase, and lipase aid in digesting proteins, starches, and fats respectively.

Process of Digestion: Small Intestine Contractions

• Two main types:
  • Segmentation contractions mix intestinal contents.
  • Peristalsis propels contents towards the colon.

Process of Digestion: Ingestion of Food

• Carbohydrates are broken down into disaccharides and monosaccharides (glucose).
• Glucose is used by body cells for energy.
• Proteins are broken down into amino acids and peptides.
• Fats are emulsified, becoming monoglycerides and fatty acids.
• Chyme, partially digested food mixed with gastric secretions, remains in the small intestine for 3 to 6 hours.

Assessment of the Gastrointestinal System: Pain

• Important symptom of GI disease, especially abdominal pain.
• Characterization is crucial: duration, pattern, frequency, location, and referred pain distribution.

Assessment of the Gastrointestinal System: Dyspepsia

• Commonly described as upper abdominal discomfort after eating.
• Also called indigestion.
• Affects 25% to 40% of the population.
• Fatty foods often cause more discomfort.

Assessment of the Gastrointestinal System: Intestinal Gas

• Accumulation of gas can cause belching or flatulence.
• Symptoms relate to bloating and distention.
• Can be a symptom of food intolerance or gallbladder disease.

Assessment of the Gastrointestinal System: Nausea and Vomiting

• Nausea is a vague discomfort; vomiting may or may not follow.
• Causes are numerous, including side effects of medications, side effects of medical procedures, inner ear disorders, torsion or trauma in certain organs, and anxiety.

Assessment of the Gastrointestinal System: Bowel Habits and Stool Characteristics

• Changes in bowel habits may indicate colonic dysfunction or disease.
• Diarrhea is characterized by increased frequency and liquidity of stool.
• Constipation is a decrease in stool frequency, with hard, dry stool.
• Stool color, consistency, and presence of blood can be important diagnostic clues.

Physical Assessment: Oral Cavity

• Inspection and palpation of the oral cavity, including lips, gums, and tongue is important for assessment of GI health

Physical Assessment: Abdominal Inspection, Auscultation, Percussion and Palpation

• Auscultation precedes percussion and palpation.
• Percussion evaluates organ size and density; while palpation identifies tenderness or masses.

Physical Assessment: Rectal Inspection and Palpation

• Postions for rectal exams include knee-chest, left lateral, or standing positions.
• Examinations can identify rectal abnormalities.

Diagnostic Evaluation/Laboratory: Serum Laboratory Studies

• CBC, PT, PTT, Triglycerides, Liver Function Test, Amylase, and Lipase.

Diagnostic Evaluation/Laboratory: Stool Tests

• Stool color, consistency, and occult blood are assessed.
• Guaiac-based fecal occult blood testing (gFOBT) is used often for detecting early cancer.

Diagnostic Evaluation/Imaging: Abdominal Ultrasonography

• Noninvasive technique using high-frequency sound waves to image internal structures.
• Useful for detecting enlarged gallbladder or pancreas, gallstones, and other abnormalities.
• Less costly and does not involve radiation.
• Not suitable for imaging structures behind bone.

Diagnostic Evaluation/Imaging: Endoscopic Procedures (Upper Gastrointestinal)

• Esophagogastroduodenoscopy (EGD), is used to visualize the esophagus, stomach, and duodenum.
• This procedure is used for detecting and treating various esophageal, gastric, and duodenal disorders.

Diagnostic Evaluation/Imaging: Endoscopic Procedures (Lower Gastrointestinal)

• Colonoscopy is a procedure that uses a flexible tube with a camera to view the inside of the colon and rectum.
• Used for detecting colorectal cancer, polyps, and other conditions.

Diagnostic Evaluation/Imaging: Computed Tomography (CT)

• CT provides cross-sectional images of abdominal organs and structures.
• Useful for diagnosing inflammatory conditions of the colon, including appendicitis, diverticulitis, regional enteritis, and ulcerative colitis.
• May be performed with or without contrast.

Diagnostic Evaluation/Imaging: Magnetic Resonance Imaging (MRI)

• Noninvasive technique that uses magnetic fields and radio waves to produce images.
• Useful for evaluating abdominal soft tissues, blood vessels, abscesses, fistulas, and other sources of bleeding.
• Patients with metal implants may not be able to undergo this procedure.

Diagnostic Evaluation/Imaging: Positron Emission Tomography (PET)

• Uses radioactive substances to capture and view activity within the GI tract.
• Provides critical information for staging conditions.

Nursing Interventions: Endoscopic Procedures

• Preparation for procedures: NPO status, local anesthetic application, and position adjustments.
• Post-procedure monitoring: vital signs, consciousness level, pain assessment, and respiratory distress observation.

Nursing Interventions: Fiberoptic Colonoscopy

• Colon preparation, position for examination.
• Vital signs, assessment of comfort during examination.
• Post-procedure recovery and monitoring.