Digestive System

A set of vocabulary flashcards covering key terms related to the digestive system.

Alimentary canal

Continuous muscular tube running from mouth to anus, part of the GI tract.

Mucosa

Innermost layer of the digestive tract, secretes mucus.

Submucosa

Connective tissue layer containing blood vessels and glands.

Muscularis

Layer of muscle in GI tract; inner circular and outer longitudinal layers.

Serosa

Outermost layer; serous membrane present in abdominal cavity.

Cranial Nerves

Nerves that control taste (CN VII and IX) and swallowing (CN V, VII, IX, X, XII).

Enteric Nervous System

Nervous system of the GI tract that controls motility.

Myenteric nerve plexus

Controls GI tract motility.

Submucosal nerve plexus

Regulates glands and smooth muscle in the mucosa.

Sympathetic system

Inhibits digestion and motility.

Parasympathetic system

Increases digestive processes like motility and secretion.

Arterial circulation

Branches off aorta that serve digestive organs.

Hepatic portal circulation

Carries nutrient-rich blood from small intestine to liver.

Visceral peritoneum

Membrane on the external surface of abdominal organs.

Parietal peritoneum

Membrane that lines the body wall in the abdominal cavity.

Mesentery

Folds that anchor the small intestine.

Haustra

Winkled pouches in the colon due to teniae coli.

Bolus

Chewed food mass ready for swallowing.

Chyme

Semiliquid food mass that enters the small intestine.

Deglutition

Swallowing process.

Mastication

Chewing process.

Rugae

Folds in the stomach that allow for expansion.

Gastric mucosa

Mucous membrane layer of the stomach.

Intrinsic factor

Protein essential for vitamin B12 absorption.

Chief cells

Cells in the stomach that secrete pepsinogen.

Pepsinogen

Inactive enzyme converted to pepsin by hydrochloric acid.

Duodenum

First section of the small intestine, approximately 10 inches long.

Jejunum

Middle section of the small intestine, approximately 8 feet long.

Ileum

Final section of the small intestine, approximately 12 feet long.

Villi

Finger-like projections of mucosa in the small intestine for absorption.

Microvilli

Extensions on epithelial cells that further increase absorption surface area.

Peyer’s patches

Collections of lymphatic tissue in the intestine that prevent bacteria from entering blood.

Segmentation

Local constriction of intestine to mix food with digestive juices.

Digestive enzymes

Biological catalysts that break down food molecules.

Cecum

First part of the large intestine.

Colon

Main part of the large intestine, divided into ascending, transverse, descending, and sigmoid.

Rectum

Final portion of the large intestine before the anus.

Sphincter

Muscle that controls the passage of contents at certain locations.

Goblet cells

Mucus-secreting cells found in the mucosa of the large intestine.

Mechanical digestion

Physical processes that break down food (e.g., chewing).

Chemical digestion

Chemical processes that break down food into smaller components.

Defecation

Elimination of indigestible substances from the GI tract.

Bile

Substance produced by the liver that emulsifies fats.

Gallbladder

Organ that stores bile produced by the liver.

Pancreas

Organ that secretes digestive enzymes and bicarbonate.

Amylase

Enzyme that breaks down carbohydrates.

Protease

Enzyme that breaks down proteins.

Lipase

Enzyme that breaks down lipids.

Nuclease

Enzyme that breaks down nucleic acids.

Emulsification

Process of breaking down large fat globules into smaller ones using bile.

Monosaccharides

Simple sugars such as glucose and fructose.

Polysaccharides

Complex carbohydrates made of long chains of monosaccharides.

Amylase

Enzyme that begins carbohydrate digestion in the mouth.

Pepsin

Enzyme that digests proteins in the stomach.

Absorption

Movement of digested products from the GI tract into blood or lymph.

Nutrient-rich blood

Blood that contains absorbed nutrients from the intestine.

Fat-soluble vitamins

Vitamins A, D, E, and K absorbed with dietary fats.

Water-soluble vitamins

Vitamins B and C absorbed with water or active transport.

Intrinsic factor

Required for the absorption of vitamin B12 in the small intestine.

Haustral contractions

Sequential contractions in the colon that aid in moving contents.

Mass movement

Strong peristaltic contractions that move contents in the colon toward the rectum.

Defecation reflex

Reflex that stimulates the urge to expel feces.

Liver

Organ that produces bile and processes nutrients.

Hepatitis

Inflammation of the liver.

Pancreatitis

Inflammation of the pancreas.

Peptic ulcer

Open sore in the stomach or duodenum lining.

Gastroesophageal reflux disease (GERD)

Chronic condition where stomach acid flows back into the esophagus.

Diverticulitis

Inflammation of diverticula in the colon.

Irritable bowel syndrome (IBS)

Disorder affecting the large intestine causing bloating and discomfort.

Celiac disease

Autoimmune disorder where ingestion of gluten leads to damage in the small intestine.

Lactose intolerance

Inability to digest lactose due to lack of lactase enzyme.

Bacterial flora

Bacteria in the gastrointestinal tract that aid in digestion and metabolism.

Fermentation

Process by which bacteria in the large intestine breakdown carbohydrates.

Homeostasis

Maintaining stable internal conditions within the body.

Metabolism

All chemical processes involved in maintaining life.

Nutrient absorption

Process by which the body takes in nutrients from food.

Hydrochloric acid (HCl)

Strong acid produced by the stomach to aid digestion.

Vascularisation

Formation of blood vessels within tissue.

Gastrin

Hormone that stimulates gastric acid secretion from stomach.

Secretin

Hormone that stimulates pancreas to release bicarbonate.

Cholecystokinin (CCK)

Hormone that stimulates gallbladder contraction and release of bile.

Phase of digestion

Stages including ingestion, propulsion, digestion, absorption, and defecation.