Digestive System Flashcards

Flashcards on the digestive system and related concepts.

Gastrointestinal Tract (GI Tract)

A tube-like structure made of many organs that allow food to pass through the digestive system.

Mucosa

The innermost layer of the GI tract.

Lamina Propria

Connective tissue found underneath the mucosal epithelium.

Muscularis Mucosae

Smooth muscle layer underneath the lamina propria in the mucosa, causing involuntary twitches.

Submucosa

Layer underneath the mucosa made up of moderately dense connective tissue with elastic fibers, lymph nodes, blood vessels, and submucosal glands.

Submucosal Glands

Glands found in the submucosa that secrete seromucous secretions.

Muscularis Externa

Layer with an inner circular layer and outer longitudinal layer of smooth muscles responsible for peristalsis and segmentation.

Serosa

Outermost layer made of visceral peritoneum, parietal peritoneum, and the peritoneal cavity with serous fluid for lubrication.

Adventitia

Dense irregular connective tissue layer that protects the organ from abrasion, keeps it together, and provides attachment to surrounding structures.

Peristalsis

Wave of contraction that pushes material in one direction in the GI tract.

Segmentation

Process useful for mixing and mechanical digestion in the GI tract.

Esophagus

The first organ of the GI tract, which has the adventitia layer and a mucosa made of non-keratinized stratified squamous epithelium.

Stomach

Organ that primarily stores food, performs mechanical digestion, and some chemical digestion; also kills bacteria with hydrochloric acid.

Rugae

Bumps on the walls of the mucosal epithelium in the stomach that increase surface area and assist in mechanical digestion.

Churning

Powerful segmentation in the stomach due to rugae and three layers of muscularis externa.

Gastric Pits

Pits in the stomach lining where new mucosal epithelial cells are made.

Diaphragm

A muscle that is important for breathing and helps with mechanical digestion.

Cardiac Sphincter

Sphincter that does not close completely, allowing air to escape from the stomach (burping).

Acid Reflux/Heartburn

Condition where stomach acid goes up into the esophagus, causing a burning sensation.

Esophageal Cancer

Condition where esophageal cells are replaced by stomach goblet cells, potentially leading to esophageal cancer.

Gastric Ulcers

Occurs when the mucosal epithelium of the stomach burns away, exposing the underlying connective tissue.

Esophageal Hiatus

Opening in the diaphragm through which the esophagus passes.

Hernia

Condition where an organ or piece of organ sticks out in a place where it does not belong, e.g., the stomach going through the esophageal hiatus.

Gastric Bypass

Surgery to bypass the stomach and send food directly to the small intestine for weight loss reasons.

Small Intestine/Small Bowel

Longest part of the gastrointestinal tract where almost all chemical digestion and absorption occur.

Duodenum

First part of the small intestine that receives secretions from the pancreas, liver, and gallbladder.

Bicarbonates

Substance released by the pancreas to neutralize the stomach's acidity in the duodenum.

Bile

Emulsifier from the liver and gallbladder that breaks down fats into smaller globs to increase surface area for digestion.

Jejunum

Where most digestion occurs, receiving digestive enzymes, mucus, bicarbonate, and bile from the duodenum.

Ileum

The longest section of the small intestine, where most absorption occurs.

Plaque Circulars

Folds in the small intestine that increase surface area for digestion and absorption.

Villus/Villi

Extensions coming out from the plaque circulars to further increase surface area.

Microvilli

Smaller versions of villi on the columnar cells of the villi to increase surface area.

Intestinal crypts

Regions that dip down in the small intestine where new mucosal epithelial cells are made.

Lacteal

Lymphatic capillary found in the villus that is capable of fat absorption.

Large Intestine

Intestine that stores feces, reabsorbs water, and stores beneficial bacteria; wider in diameter than the small intestine.

Water Absorption/Reabsorption

Reabsorption of water from the fecal matter in the large intestine.

Beneficial Bacteria

A symbiotic relationship, where organisms live in the large intestine benefiting from a warm environment, water, and waste, while providing us with vitamin B12 and K.

Fecal Transplant

Restoring beneficial bacteria by transplanting fecal bacteria from a healthy person; by wash away and bacteria via suppository/oral medication.