Med-Surg Chp 44

INTRODUCTION TO THE GASTROINTESTINAL SYSTEM AND ACCESSORY STRUCTURES

Overview

This section covers the foundational aspects of the gastrointestinal (GI) system including its anatomy, physiology, and nursing assessments related to it.

STUDENT LEARNING OBJECTIVES

  1. Identify major organs and structures of the gastrointestinal system.

  2. Discuss important information to ascertain about gastrointestinal health.

  3. Identify facts in the client’s history that provide pertinent data about the present illness.

  4. Discuss physical assessments that are pertinent to gastrointestinal tract function.

  5. Describe common diagnostic tests performed on clients with gastrointestinal disorders.

  6. Describe nursing measures after liver biopsy.

  7. Explain nursing management of clients undergoing diagnostic testing for a gastrointestinal disorder.

ANATOMY AND PHYSIOLOGY

Sections of the GI System

The GI system is divided into three main sections:

  • Upper GI: from the mouth to the pyloric sphincter

  • Middle GI: consisting of the small intestine, which includes:
      - Duodenum
      - Jejunum
      - Ileum

  • Lower GI: includes the cecum to the anus

Key Components of the GI System
1. Mouth

  • Function:
      - Mastication (chewing) of food containing starch;
      - Partial digestion involving the enzyme salivary amylase.

2. Esophagus

  • Location: Located between the mouth and stomach; composed of muscle tissue.

  • Function: Responsible for peristalsis, which is the wave-like muscle contraction that moves food towards the stomach.

  • Includes the upper esophageal sphincter and the hiatus.

3. Stomach

  • Function: Holds ingested food temporarily; processes it into a semiliquid form called chyme.

  • Sphincters:
      - Cardiac sphincter: between esophagus and stomach,
      - Pyloric sphincter: between stomach and duodenum.

  • Gastric Secretions: Chyme consists of gastric juices mixed with partially digested food.

4. Small Intestine

  • Primary function: Absorption of nutrients from chyme.

  • Comprised of three parts:
      - Duodenum
      - Jejunum
      - Ileum

  • Ileocecal valve: Regulates flow of intestinal contents into the large bowel (cecum) from the small intestine.

5. Large Intestine

  • Primary Function: Receives waste from the small intestine, absorbing water and some electrolytes.

  • Structure:
      - Cecum
      - Colon: ascending, transverse, descending, and sigmoid segments
      - Rectum
      - Anal canal
      - Appendix

ACCESSORY STRUCTURES

Accessory Digestive Organs

  1. Liver:
       - Largest glandular organ in the body.
       - Functions include detoxification, protein synthesis, and production of biochemicals necessary for digestion.

  2. Gallbladder:
       - Stores and concentrates bile.
       - Upon contraction, releases bile into the small intestine for digestion.

  3. Pancreas:
       - Serves as both an exocrine and endocrine gland.
       - Endocrine Function: Produces hormones such as insulin and glucagon.
       - Exocrine Function: Secretes digestive enzymes for proteins, fats, and carbohydrates.

PERITONEUM

  • Definition: A silk-like membrane that lines the inner abdomen, enclosing the viscera and secreting serous fluid.

  • Function: Facilitates movement of abdominal organs without friction.

  • Clinical Implication: A perforation in the digestive tract can lead to peritonitis, which is severe inflammation of the peritoneum due to the entry of microorganisms and digestive enzymes.

NURSING ASSESSMENT

History Assessment

  • The history aims to identify the client's specific GI problem and its potential causes.

  • Components of History:
      - Chief complaint
      - Focus assessment covering:
        - Nutritional status and patterns
        - Metabolic patterns
        - Elimination patterns
      - Past medical and family history, especially related to colorectal cancer.

Physical Examination

  1. General Appearance Assessment:
       - Factors like height, weight, age, vital signs, and mental status are critical for overall evaluation.
       - Terms used must include descriptions such as:
         - Fit/Fluffy, Cachectic/Obese, Healthy glow/Sallow
         - Alert/Lethargic, Engaged/Withdrawn

  2. Skin Examination:
       - Signs of jaundice, spider angiomas (spider-shaped blood vessel patterns), and caput medusae (distended abdominal veins).

  3. Oral Cavity Examination:
       - Check for denture fit, lip sores, oral inflammation, and dental health.

  4. Abdominal Assessment:
       - Position the patient supine with knees flexed to promote relaxation.
       - Assessment Techniques:
         - Inspection: Observe contour (flat, round, concave, distended).
         - Auscultation: Listen for bowel sounds: absent, normal, hypoactive, or hyperactive.
         - Percussion and Palpation: Tap to locate organ borders and assess tenderness, mass, etc.

  5. Anus Examination: Check for external hemorrhoids, skin tags, fissures, and stool characteristics (shape, color, consistency).

DIAGNOSTIC TESTS

Overview of Diagnostic Tests

The following provides a comprehensive view of common diagnostic tests performed on clients with gastrointestinal disorders:

  1. Radiographic Studies:
       - Useful for identifying the location and structural appearance of GI organs.
       - Involves the use of radiopaque contrast media and fluoroscopy.

  2. Barium Swallow/Upper Gastrointestinal Series:
       - Involves fluoroscopic observation for detecting abnormalities in the esophagus.
       - Requisites: Low-residue diet, laxative use, and abstaining from smoking.
       - Post-procedure guidance includes drinking fluids and monitoring stool color.

  3. Small Bowel Series:
       - Examines the small intestine using fluoroscopy to identify obstructions or tumors.

  4. Barium Enema/Lower GI Series:
       - Identifies abnormalities such as polyps or tumors in the large intestine.
       - Pre and post-testing requirements include dietary restrictions and preparation procedures.

  5. Oral Cholecystography/Gallbladder Series:
       - Assesses gallbladder function and stone presence using iodine-based contrast medium.
       - Clients must refrain from eating before the test and take specific preparatory tablets.

  6. Cholangiography:
       - Determines the patency of bile ducts using various methods including ERCP.
       - Education emphasizes the need for client cooperation during positioning.

  7. Radionuclide Imaging:
       - Leverages radionuclide for detecting lesions in the liver or pancreas; involves IV or oral administration of diagnostics.

  8. Magnetic Resonance Imaging (MRI):
       - Uses magnetic energy for examination avoiding radiation exposure.
       - NPO requirements and removal of metal objects are critical for safety.

  9. Ultrasonography:
       - Uses sound waves for visualizing organ size and location; aids in diagnosing conditions like cholelithiasis.

  10. Laboratory Tests:
       - Encompasses various blood tests (complete blood count, liver function tests, etc.) and stool analyses (occult blood, fat, etc.) for assessing gastrointestinal health.

POST-TEST PROCEDURES: LIVER BIOPSY

Nursing Measures

  • Verify informed consent and coagulation status prior to the procedure.

  • Monitor vital signs and instruct the client on postoperative positioning.

  • Advise clients to remain in bed for 8-12 hours post-biopsy and to avoid certain activities that could risk bleeding.

  • Provide discharge instructions regarding what to monitor post-procedure, including signs of complications such as severe pain or fever.

This study guide encompasses the anatomy, physiology, and nursing assessments of the gastrointestinal system thoroughly, ensuring that all key concepts are addressed with the depth required for a comprehensive understanding.