GI

upper GI tract

Any changes in the integrity of the structures of the oral environment and salivary glands can compromise the initial breakdown of food and alter digestion

saliva has a low pH and lots of liquid, so the acidic environment helps break down food

mechanical = physical breakdown

chemical = enzymatic breakdown

parts of the upper GI tract = mouth, salivary glands, esophagus, and stomach

• mouth

• salivary glands

• esophagus

  • Approximately 10 inches long tube that leads from the throat to the stomach

  • positioned behind the trachea

    • upper esophageal sphincter

      • closed at rest

      • blocks air into the esophagus and blocks aspiration of substances into the airway

    • lower esophageal sphincter

      • closed at rest

      • relaxation is managed by the afferent sensory branch of the vagus merve

      • prevents regurgitation of stomach acid

• stomach

  • connects to the LES

  • muscular, hollow organ

  • storage and absorption of fat soluble minerals

  • secrets digestive juices (enzymes) to break down food into smaller particles

  • muscles churn the mixture

  • distal part of the stomach connects to the duodenum by way of the pyloric sphincter

  • parietal cells: specialized epithelial cells that secrete hydrochloric acid and intrinsic factor

lower GI tract

• small intestine

• large intestine

organs

• liver

  • spongy, wedge-shaped, reddish-brown color

  • regenerative

  • regulates blood sugar

  • role of the liver:    

    • breaks down RBC

    • regulates chemical makeup of blood

    • regulates clotting

    • produces and detoxifies hormones

    • helps absorb vitamins

    • deactivates toxins

    • produces bile

    • produces proteins and cholesterol

    • controls metabolic processes → fats, carb, proteins

• pancreas

• enzymes

  • amylase: a component of saliva that helps breakdown starches, polysaccharides and complex carbs

  • protease: breaks down proteins and polypepetides

  • lipase: aids in digestion and absorption of fats

• gallbladder

  • pear shaped organ

  • reservoir that stores and releases bile

  • bile passes from gallbladder throughout the common bile duct into the duodenum

  • digests fatty foods

  • absorbs fat soluble vitamins

  • carries waste out of liver

lower GI tract

• approximately 16.4 ft in length

• long, tubular structure

• absorbs nutrients from foods

• divided into 3 sections

  • duodenum

  • jejunum

  • ileum

small intestines → digests contents from stomach

• absorbs water and salt from food aka electrolytes, creating solid waste

• 6 main parts

  • cecum

  • ascending colon

  • transverse colon

  • descending colon

  • sigmoid colon

  • rectum

large intestines

• key signs and symptoms

  • abdominal pain

  • nausea and vomiting

  • diarrhea

  • constipation

  • abdominal distention

  • melena: black, tarry stool

  • hematochezia: red or maroon blood in stool

  • jaundice

    • assessment

      • inspection

      • auscultation

      • percussion

      • palpation

• nursing priorities

  • assess bowel function

  • fluid and electrolyte balance

  • nutrition

  • recognize red flags

upper GI disorders

• GERD

• hiatal hernia

• gastroparesis

• gastritis

• ulcers

diagnostics

• guaiac test = stool sample to test for blood

• colonoscopy = endoscope inserted through anus to visualize colon

• EGD = endoscope inserted through mouth to visualize upper GI and duodenum

• small bowel series = x rays taken after ingestion of contrast media to obtain picture of small bowel