The Digestive System

A comprehensive set of flashcards covering the key vocabulary and concepts of the digestive system.

Digestion

The process by which food substances are changed into forms that can be absorbed through cell membranes.

Gastrointestinal (GI) tract

Also known as the alimentary canal; a continuous tube from mouth to anus through which food passes.

Ingestion

The act of taking food into the digestive tract.

Propulsion

The movement of food through the GI tract, including swallowing and peristalsis.

Secretion

The release of water, acid, buffers, and enzymes into the lumen of the GI tract.

Mechanical digestion

The physical breakdown of food, including chewing and mixing with saliva.

Chemical digestion

The enzymatic breakdown of food into simpler molecules.

Absorption

The uptake of digested nutrients from the intestinal cells into the bloodstream.

Defecation

The elimination of indigestible substances from the body as solid waste (feces).

Mucosa

The innermost lining of the GI organs, consisting of epithelium and connective tissue.

Submucosa

Layer of areolar connective tissue that contains blood vessels and nerve plexuses.

Muscularis externa

Layer composed of smooth and skeletal muscles; responsible for peristalsis and segmentation.

Serosa

Outer layer of the GI tract made of connective tissue and simple squamous epithelium.

Salivary glands

Glands that secrete saliva; include parotid, submandibular, and sublingual glands.

Teeth

Structures in the mouth that mechanically break down food during chewing.

Tongue

Muscular organ that aids in mixing food and initiating swallowing.

Pharynx

Throat; the passageway for food to the esophagus and air to the larynx.

Esophagus

The muscular tube that conveys food from the pharynx to the stomach.

Stomach

The J-shaped organ that stores and digests food.

Duodenum

The first part of the small intestine, where the majority of digestion occurs.

Jejunum

The middle section of the small intestine where absorption occurs.

Ileum

The final section of the small intestine before it joins the large intestine.

Cecum

The beginning of the large intestine, where the appendix is attached.

Colon

Part of the large intestine containing ascending, transverse, descending, and sigmoid regions.

Rectum

The final section of the large intestine, leading to the anus.

Gallbladder

The organ that stores and concentrates bile produced by the liver.

Liver

The organ responsible for metabolic regulation, blood filtration, and bile production.

Pancreas

An accessory organ that secretes enzymes and buffers into the small intestine.

Cholecystokinin (CCK)

A hormone that stimulates the gallbladder to contract and release bile.

Secretin

A hormone that stimulates the pancreas to secrete bicarbonate and liver to produce bile.

Gastric Juice

A mixture of acids and enzymes secreted by the stomach for digestion.

Intrinsic factor

A glycoprotein required for the absorption of vitamin B12 in the intestine.

Cirrhosis

A chronic liver disease caused by excessive alcohol consumption or viral infection.

Hepatitis

Inflammation of the liver, often caused by viral infections.

Bile

A digestive fluid produced by the liver that helps emulsify fats.

Haustra

Pouches in the large intestine that allow for expansion and contraction.

Peristalsis

Waves of muscular contractions that move food through the digestive tract.

Mas Peristalsis

A strong peristaltic wave that drives contents of the colon into the rectum.

Dysphagia

Difficulty swallowing, could be due to various health issues.

Diarrhea

Excessively watery stool resulting from rapid passage through the intestines.

Constipation

Difficulty in passing stool or infrequent bowel movements.

Bristol Stool Chart

A medical aid to classify the form of human feces into seven categories.

Colitis

Inflammation of the colon, sometimes caused by infections.

Irritable bowel syndrome

A common disorder affecting the large intestine, characterized by abdominal pain.

Filiform papillae

Tongue structures that provide roughness and friction.

Fungiform papillae

Tongue structures scattered across the surface that contain taste buds.

Circumvallate papillae

Large V-shaped structures at the back of the tongue that contain taste buds.

Foliate papillae

Structures located on the lateral aspects of the posterior tongue.

Lingual frenulum

A fold of tissue that attaches the tongue to the floor of the mouth.

Bolus

A rounded mass of food ready to be swallowed.

Esophageal sphincter

Muscle that controls the passage of food from the esophagus to the stomach.

Pyloric sphincter

Muscle that regulates the passage of chyme from the stomach to the small intestine.

Enzymatic breakdown

The process by which enzymes convert complex molecules into simpler forms.

Hydrolysis

A chemical process that splits molecules by adding water.

Nucleic acids

Biomolecules that are essential for all known forms of life, involved in genetic information.

Electrolytes

Ions that are essential for various bodily functions, including fluid balance and nerve function.

Lacteals

Lymphatic capillaries in the small intestine that absorb dietary fats.

Goblet cells

Cells in the intestinal epithelium that secrete mucus.

Paneth cells

Cells in the intestine that secrete antimicrobial molecules such as lysozyme.

Ascitic fluid

Fluid that accumulates in the abdominal cavity, often due to liver dysfunction.

Insulin

A hormone produced by the pancreas that regulates blood sugar levels.

Metabolism

The process by which the body converts food into energy.

Vagus nerve

A cranial nerve that controls various functions, including digestion.

Metabolic regulation

The process by which the liver regulates the production and breakdown of substances.

Phagocytosis

The process by which cells ingest or engulf other cells or particles.

Hepatic lobules

The functional units of the liver, involved in detoxification and metabolism.

Cystic duct

Duct that connects the gallbladder to the common bile duct.

Cholecystitis

Inflammation of the gallbladder, often related to gallstones.

Biliary calculi

Gallstones; solid particles that form from bile cholesterol and bilirubin.

Glucose

A simple sugar that is an important energy source in living organisms.

Glycogen

The storage form of glucose in the liver and muscles.

Peptidase

An enzyme that breaks down peptides into amino acids.

Articulatory system

The system involved in the formation of speech sounds.

Absorptive phase

The phase in which nutrients are absorbed following a meal.

Post-absorptive phase

The phase after absorption, characterized by the use of stored nutrients.

Vitamin storage

The liver’s function of storing vitamins needed by the body.

Detoxification

The process by which the liver removes or neutralizes toxins.

Fat emulsification

The process by which bile breaks down fat into smaller droplets for digestion.

Appendix

A small, tube-like structure attached to the cecum, often considered vestigial.

Histamine

A compound involved in local immune responses and regulation of gastric acid.

Gastric acid

The digestive fluid produced in the stomach, primarily composed of hydrochloric acid.

Electrolyte imbalance

A disturbance in the balance of electrolytes in the body, often affecting function.

Dietary fiber

Plant-based carbohydrates that are poorly digested but beneficial for digestive health.

Chyme

Partially digested food mixed with gastric juices, moving from the stomach to the small intestine.

Antigen presentation

The process by which immune cells present foreign substances to T-cells.

Feces

The solid waste product eliminated from the digestive tract.

Hydration

The process of absorbing or retaining water in bodily tissues.

Mucosal lining

The protective layer of the gastrointestinal tract that facilitates absorption and secretion.

Buccal Phase

Phase of swallowing where bolus is compressed against the hard plate; the tongue then pushes it into the oropharynx.

Pharyngeal Phase

Phase were the swallowing reflex is stimulated by the uvula; medulla triggers muscular contractions; bolus passes over the epiglottis

Esophageal Phase

Bolus is pushed toward the stomach; peristalsis moves the bolus through the esophagus into the stomach.

Gastric Villi

Gastric pits/glands that secrete gastric juice. They increase the surface area for absorption.

Cephalic Phase

The phase that occurs before food enters the stomach; duration = minutes; triggers vagus nerve and stimulates gastric secretions and motility.

Gastric Phase

The phase of digestion when food enters the stomach, stimulating gastric secretions and contractions. It lasts several hours and is primarily regulated by neural and hormonal mechanisms.

Intestinal Phase

The phase of digestion that occurs when chyme enters the small intestine, promoting further digestive secretions and nutrient absorption. It is mediated by both hormonal and nervous signals.

Pancreatic Amylase

An enzyme produced by the pancreas that breaks down carbohydrates into simple sugars, facilitating digestion in the small intestine.

Pancreatic Lipase

An enzyme produced by the pancreas that aids in the digestion of lipids (fats) in the small intestine by breaking them down into fatty acids and glycerol.

Proteolytic enzymes

enzymes that break down proteins into smaller peptides and amino acids during digestion.

Nucleases

are enzymes that hydrolyze nucleic acids (DNA and RNA) into smaller nucleotides, facilitating their digestion in the small intestine.

Inflammatory Bowl Disease

inflammation of the large and sometimes small intestines