The Human Digestive Tract Flashcards

Vocabulary flashcards about the human digestive tract.

Mucosa

The innermost layer lining the lumen of the GI tract

Submucosa

Layer of connective tissue that contains blood vessels, lymphatics, and nerves; supports the mucosa & helps regulate secretions and local blood flow.

Muscularis

Inner circular and outer longitudinal layer responsible for peristaltic movements.

Serosa

Outermost layer that anchors and protects the digestive tract.

Stratified Squamous

Epithelium type found in the oral cavity, providing protection.

Nonkeratinized Stratified Squamous

Epithelium type found in the esophagus, specialized for protection.

Simple Columnar

Epithelium type found in the stomach, specialized for secretion.

Simple Columnar with Microvilli and Goblet Cells

Epithelium type found in the small intestine, specialized for absorption and secretion.

Simple Columnar with Many Goblet Cells

Epithelium type found in the large intestine, specialized for water absorption and lubrication.

Lamina Propria

A part of the mucosa made of loose connective tissue that supports the epithelium, allows nutrient diffusion, and provides immune defense.

Submucosa

A denser connective tissue layer located below the mucosa; contains blood vessels, lymphatics, and Meissner’s plexus.

Esophageal Glands

Glands found in the esophagus within the submucosa.

Brunner’s Glands

Glands located in the duodenum (first part of the small intestine) secreting alkaline mucus.

Stratified Squamous Epithelium

Epithelium that protects against mechanical stress from chewing and food particles in the mouth, tongue, and hard palate.

Esophageal Glands

Secrete mucus to lubricate the esophagus, making it easier for food to pass down without damaging the lining.

Adventitia

Anchors the esophagus to surrounding structures like the trachea and vertebrae.

Chyme

Acidic secretions produced in the stomach.

Lipase

Enzyme that starts the digestion of fats in the stomach.

Pepsin

Enzyme that initiates protein digestion in the stomach.

Surface Mucous Cells

Secrete thick mucus that protects the stomach lining from corrosive effects of stomach acid and enzymes.

Gastric pits

Small depressions of the epithelial surface in the stomach.

Gastric Glands

Tubular glands located beneath the gastric pits containing specialized cells.

Parietal Cells

Cells in the stomach that secrete HCl and intrinsic factor.

Chief Cells

Cells in the stomach that secrete pepsinogen.

Mucous Neck Cells

Cells in the stomach that secrete mucus.

Enteroendocrine Cells

Cells in the stomach that secrete gastrin.

Hydrochloric Acid (HCl)

Activates pepsin, kills microbes, and helps digest proteins.

Bicarbonate

Ensures that the stomach lining doesn’t get damaged by acid.

Somatostatin

Hormone that inhibits secretion from other DNES cells nearby.

Serotonin

Hormone that increases gut motility.

Gastrin

Hormone that stimulates gastric acid secretion.

Cholecystokinin (CCK)

Hormone that promotes pancreatic enzyme secretion and gallbladder contraction.

Gastric Inhibitory Polypeptide (GIP)

Hormone that inhibits gastric acid secretion.

Glucagon-Like Peptide (GLP-1)

Hormone that stimulates insulin secretion and inhibits gastric acid secretion.

Peptide YY

Hormone that promotes H2O and electrolyte absorption in the large intestine and inhibits gastric acid secretion.

Motilin

Hormone that increases gut motility.

Secretin

Hormone that inhibits gastric acid secretion.

Pyloric Sphincter

The middle circular layer that thickens at the end of the stomach, regulating passage of chyme into the duodenum.

Villi and Microvilli

Increase surface area for nutrient absorption in the small intestine.

Goblet Cells

Secrete mucus to protect and lubricate the small intestine lining.

Crypts of Lieberkühn

Contain stem cells and Paneth cells in the small intestine.

Enteroendocrine cells

Secrete hormones that coordinate digestion in the small intestine.

Peyer’s Patches

Provide immune defense against gut pathogens in the small intestine; located in the ileum.

Brunner’s Glands

Secrete alkaline mucus to neutralize acidic chyme; located in the duodenum.

Myenteric (Auerbach’s) Plexus

Controls peristalsis; located in between inner circular and outer longitudinal layer of the small intestine.

Teniae Coli

Longitudinal muscle forms these in the large intestine.

Diverticulosis

Outpouchings of mucosa/submucosa through muscularis externa.

Rectum

Site where stool accumulates before elimination.

Anus

Exit point for food waste.

Muscularis mucosae

Thin layer of smooth muscle in the rectum