Gastrointestinal System, Diagnostic Procedures, Disorders, and Enteral Nutrition

Gastrointestinal (GI) Tract Length

The long muscular continuous tube extending from the mouth to the anus, measuring $7.9\,\text{meters}$ ($23$ to $26\,\text{feet}$) in length.

Chyme

The semi-fluid mass of broken-down food created when swallowed food mixes with saliva and digestive enzymes in the oral cavity and stomach.

Amylase

A major digestive enzyme produced by the salivary glands in the oral area that combines with ingested food to initiate carbohydrate breakdown.

Upper Esophageal Sphincter

A muscular valve located at the top of the esophagus that remains closed at rest to prevent air from entering during respiration and keep food moving downward.

Lower Esophageal Sphincter

The muscular valve connecting the esophagus to the stomach that must close completely to prevent acidic stomach contents from refluxing back into the esophagus.

Kupfer Cells

Specialized cells located within the liver that engulf harmful bacteria and dispose of improperly formed or damaged red blood cells.

Hepatic Artery Blood Supply

The primary blood supply to the liver, providing approximately $1500\,\text{mL}$ of blood flow through the organ every minute.

Gallbladder

A small pear-shaped organ lying beneath the liver that collects, concentrates, stores, and releases bile into the duodenum through the biliary tract when fat is present.

Red Pulp and White Pulp

The two functional tissues of the spleen; red pulp filters blood cells to rid old and damaged ones, while white pulp contains T and B cells for the immune response.

Parietal Cells

Cells lining the stomach wall that secrete hydrochloric acid and produce intrinsic factor, which is essential for vitamin B12 absorption.

Helicobacter pylori (H. pylori)

An organism that embeds into the thick lining of the stomach wall, causing severe GI issues and requiring prolonged IV antibiotic therapy to eradicate.

Pyloric Sphincter

The muscular valve connecting the pylorus of the stomach to the small intestine that prevents acidic gastric fluid from flowing back and forth into the less acidic intestine.

Small Intestine

The longest segment of the GI tract measuring $16$ to $19\,\text{feet}$ in adults, consisting of three regions: duodenum, jejunum, and ileum.

Dyspepsia

Indigestion accompanied by symptoms of abdominal fullness, bloating, early satiety, heartburn, and regurgitation; one of the most common GI complaints.

Melena

Dark, black tarry stool resulting from blood sitting in and passing through the upper gastrointestinal tract.

Clostridium difficile (C. diff)

A highly contagious bacterial infection causing foul-smelling, mucousy stool and diarrhea that spreads rapidly unless handwashing is strictly maintained.

Abdominal Assessment Sequence

The required sequence for assessing the GI tract: inspect first, then auscultate, followed by light percussion and light palpation so bowel sounds are not artificially altered.

Abdominal Bruit

A swishing sound heard over the abdominal vessels indicating an aneurysm; if heard, the nurse must refrain from palpating or percussing and notify the physician immediately.

CEA (Carcinogenic Carceoembryonic Antigen)

A tumor marker lab test used to help detect and monitor colorectal and abdominal cancers.

CA 19-9

A specific cancer antigen test used to evaluate pancreatic, colorectal, stomach, and bile duct cancers.

Versed

A sedative medication administered prior to upper GI endoscopes to lower the gag reflex, reduce anxiety, and produce amnesia.

Atropine

A medication given before upper GI scopes to decrease saliva production; it increases heart rate and is contraindicated in tachycardic patients.

Capsule Endoscopy

A diagnostic procedure where a patient swallows a small camera-containing pill that takes photos as it travels through the GI system, excreted in $1$ to $3\,\text{days}$.

GoLightly

An oral bowel evacuation solution prescribed along with clear liquid diets and enemas to cleanse the colon before a colonoscopy or sigmoidoscopy.

Wire Cutters at Bedside

An essential safety tool required at the bedside for any patient whose jaw is wired shut following surgery to allow immediate airway access in an emergency.

Hemiglossectomy

The surgical removal of half of the tongue, often performed during resection of oral cavity cancers.

Xerostomia

Severe dry mouth resulting from radiation or surgical interventions for oral cavity and pharyngeal cancers.