Digestive System Flashcards
<p>What are the parts of the digestive system? (4 plus accessory)</p>
<p>Esophagous, stomach, small intestine, large intestine, + intrinsic glands</p>
<p>What are the layers of the digestive system where it is not continuous with mesentery?</p>
<p>Mucosa, submucosa, muscularis externa & serosa</p>
<p>What are the layers of the digestive system where it is continuous with mesentery</p>
<p>Mucosa, submucosa, muscularis externa, and adventitia</p>
<p>What is the epithelium of the esophagus?</p>
<p>Stratified, squamous, nonkeratinized epithelium</p>
<p>What is the purpose of esophageal cardiac glands and esophageal glands proper?</p>
<p>Secrete mucous and some secrete serous cells and lysozyme</p>
<p>Where are the mucus secreting glands located in the esophagus?</p>
<p>The lamina propria (esophageal cardiac glands) and the submucosa layer (esophageal glands proper)</p>
<p>Describe the musculature of the esophagus?</p>
<p>Upper third, striated in externa, middle third, smooth and striated, lower third, smooth</p>
<p>What is the purpose of the esophagus?</p>
<p>To convey bolus from pharynx to stomach</p>
<p>What ensures the bolus in transported one directionally?</p>
<p>2 physiologic sphincters, pharyngoesophageal and gastroesophageal</p>
<p>What sphincter initiates swallowing?</p>
<p>Upper esophageal sphincter</p>
<p>What keeps acid reflux from stomach into esophagus?</p>
<p>Lower esophageal sphincter</p>
<p>What does persistant acid reflux lead to?</p>
<p>GERD - gastroesophageal reflux disease</p>
<p>What are the symptoms of GERD over time?</p>
<p>Ulceration, difficulty swallowing (dysphagia), fibrosis and stricture of Lower esophagus</p>
<p>DDX: Abnormal growth of simple columnar cells in lower esophagous. Increased incidence of adenocarcinoma of esophagous. Increased susceptibility to injury to stomach acid injury</p>
<p>Barrett's esophagus</p>
<p>DDX: Incomplete closure of esophageal diaphram. Reflux esophagitis and ulceration. Difficulty swallowing and "lump in the throat" feeling</p>
<p>Hiatal Hernia</p>
<p>What does the stomach do to the bolus?</p>
<p>Acidifies it and converts it into chyme</p>
<p>Describe the musculature of the stomach</p>
<p>Rugae - longitudinal folds of the mucosa and submucosa which disappear when stomach is distended</p>
<p>Describe what depth of gastric pit tells you about stomach location?</p>
<p>Pits are shallowest in cardia and deepest in pylorus</p>
<p>What is the defining feature of the cardia of the stomach?</p>
<p>It is mucus secreting via tubular glands with coiled ends</p>
<p>What is the primary contributor to gastric juice? What kind of cells secrete it?
</p>
<p>The fundus is the primary contributor.
Parietal and chief cells
</p>
<p>Describe the gastric pits in the pylorus</p>
<p>Deep gastric pits with branched glands. Primary mucus secreting and some parietal cells and gastrin secreting G ccells</p>
<p>What is the epithelium of the stomach?</p>
<p>Simple columnar, mucus producing but not goblet</p>
<p>What is located in the lamina propria of the stomach?</p>
<p>Loose CT with smooth muscle, lymphocytes, plasma, mast cells, and fibroblasts</p>
<p>What is included in the gastric mucosa?</p>
<p>Epithelium, lamina propria, gastric glands, and muscularis mucosa</p>
<p>What is the muscularis mucosae?</p>
<p>A poorly defined inner circular layer and an outler longitudinal layer of smooth muscle. Sometimes has an outermost circular layer</p>
What is present in the gastric submucosa?
Desnce irregular collagenous CT with fibroblasts, mast cells, and lymphoid elements in the connective tissue
Messner’s plexus
What is present in the muscularis externa?
3 smooth muscle layers: incomplete inner oblique, thick middle circular, outer longitudinal layer
Aurbachs plexus located between middle and outer layer
Gastric serosa around whole thing
What layer of muscle makes the pyloric sphincter?
Thick middle circular
What influences the rate at which the stomach empyies?
Viscosity, pH, lipid content, osmolality, caloric density
What gastric glands are present in the fundus and body?
Simple tubular
Describe the parts of a gastric pit and what is located in each
Pit - entrance into gastric glands - contains simple columnar mucinogenic cells renewed every 3-5 days
Isthmus - connection of “fingers” of gland to the gastric pit - contains regenerative cells, neck cells, parietal cells
Neck - Entrance into each finger of the gland - Contains mucous neck cells and parietal cells
Base - bottom of fingers - contains all cells above (excluding surface cells) plus neuroendocrine cells
What do surface lining cells secrete?
Mucous granules with cloudy, thick, viscous mucous with high bicarbonate content fror acid protection
How often are surface lining cells renewed?
Every 3-5 days
What are the features of mucous gland cells? what do they secrete?
Short microvilli, apical mucous granules, prominent golgi, shorter columnar cell than surface lining
Secrete soluble mucous not as thick as surface lining
Controlled by vagal stimulation
