BIOS 251 Week 4 Case Study

2 Please address the following questions in complete sentences. 1. What type of tissue is normally found where the esophagus meets the stomach (the gastroesophageal junction)? At the normal gastroesophageal junction, there is a nonkeratinized stratified squamous epithelium - Esophagus to Simple columnar epithelium - Stomach This change is known as the squamocolumnar junction (clinically known as the “Z-line”). The squamous epithelium of the esophagus is designed to defend against abrasion by the food that is swallowed. The columnar epithelium of the stomach is made of mucus-secreting cells to defend against the stomach acid. 2. What do the terms adenocarcinoma, metaplasia, and dysplasia mean? Adenocarcinoma - cancer that develops in glandular epithelial tissue. Metaplasia - a reversible process in which one mature cell type is replaced by another mature cell type, generally as a result of persistent irritation or stress. Dysplasia - abnormal growth and development of cells that may be precancerous. 3. Why do cancers like squamous cell carcinoma often develop in the upper or middle parts of the esophagus? Squamous cell carcinoma commonly occurs in the upper and middle portions of the esophagus. The lining of the upper and middle portions of the esophagus is made of squamous epithelial cells. These cells can be damaged through chronic irritation from smoking, alcohol usage, hot beverages, etc., and become malignant. 4. Where in the body would you find simple columnar epithelium? Simple columnar epithelium is often seen lining the digestive tract, for example the stomach and intestines. It is also present in portions of the uterus and gall bladder. 5. From the information in this case, what risk factors likely contributed to Mr. Johnson developing Barrett’s esophagus? Mr. Johnson’s likely risk factors for developing Barrett’s esophagus include: Chronic gastroesophageal reflux disease (GERD) — long-term acid reflux is the major risk factor. Smoking - makes inflammation and damage to the lining of the esophagus worse. Obesity - particularly abdominal obesity, which worsens reflux. Older age and male sex; more common in older males. Barrett's Esophagus is a condition where the normal squamous lining of the lower esophagus is replaced with intestinal-type columnar tissue. This is abnormal.