Digestive System Comprehensive Review

Comprehensive vocabulary flashcards covering the anatomy, physiology, enzymes, and pathology of the digestive system based on lecture notes.

What is the primary function of the digestive system?

To break down food into absorbable nutrients.

What is the alimentary canal?

The continuous tube of the digestive system including the mouth, esophagus, stomach, and intestines; it excludes accessory organs like the liver.

What are accessory digestive organs?

Organs that assist in digestion but are not part of the alimentary canal, such as the liver, pancreas, and gallbladder.

How much saliva is produced daily?

Approximately $1-2\,L$ is produced each day.

What is the primary site of digestion?

The small intestine, where most digestion occurs.

What is the visceral peritoneum?

The serous membrane layer that directly covers the abdominal organs.

What are mesenteries?

Double layers of peritoneum that primarily function to anchor organs in place.

What are retroperitoneal organs?

Organs located behind the peritoneum, including the pancreas, kidneys, and duodenum.

What are GI tract tunics?

The four distinct tissue layers that make up the wall of the gastrointestinal tract.

What is the parasympathetic nervous system?

The division of the autonomic nervous system that generally stimulates digestive activities.

What is the myenteric plexus?

A nerve network in the GI tract wall that primarily regulates motility.

What is peristalsis?

Rhythmic propulsion of food forward through the GI tract.

What is segmentation?

Mixing contractions that primarily function to mix chyme without major forward movement.

What is mastication?

A voluntary digestive process involving chewing.

What is salivary amylase?

An enzyme in saliva that begins the digestion of carbohydrates (starch).

What is lysozyme?

An enzyme found in saliva and produced by Paneth cells that kills and destroys bacteria.

What is the type of epithelium lining most of the mouth?

Stratified squamous epithelium.

What is the epiglottis?

The structure that prevents food from entering the trachea during swallowing.

What is the upper third of the esophagus composed of?

The section of the esophagus composed of skeletal muscle.

What is the lower esophageal sphincter?

The structure whose dysfunction results in Gastroesophageal Reflux Disease (GERD).

What is receptive relaxation?

A process that allows the stomach to expand to accommodate food for storage.

What are parietal cells?

Stomach cells responsible for secreting $HCl$ and intrinsic factor.

What are chief (zymogenic) cells?

Stomach cells that produce and secrete pepsinogen.

What is intrinsic factor?

A substance required for the absorption of Vitamin $B\_{12}$; its loss causes pernicious anemia.

What is pepsinogen?

The inactive form of pepsin, secreted to prevent the auto-digestion of stomach tissue.

What is the duodenum?

The first section of the small intestine where the majority of digestion occurs.

What are villi and microvilli?

Structural adaptations that greatly increase the surface area of the small intestine for nutrient absorption.

What are Peyer's patches?

Lymphoid follicles that are most abundant in the ileum.

What are Paneth cells?

Cells in the small intestine that produce antimicrobial proteins.

What are hepatocytes?

Liver cells that produce bile.

What are Kupffer cells?

Specialized macrophages located in the liver.

What is bile?

A substance produced by the liver and stored in the gallbladder that emulsifies fats into micelles.

What are pancreatic zymogens?

Inactive proteolytic enzymes secreted by the pancreas to prevent the organ from digesting itself.

What is enteropeptidase?

An enzyme in the small intestine that activates trypsinogen into trypsin.

What is pancreatic bicarbonate?

$HCO\_3^-$; a secretion that neutralizes acidic stomach acid in the duodenum.

What is pancreatic amylase?

An enzyme from the pancreas that continues the digestion of carbohydrates.

What is the brush border?

The layer of microvilli on epithelial cells where contact digestion occurs.

What is pancreatic lipase?

An enzyme that digests triglycerides.

What are lacteals?

Lymphatic capillaries in the small intestine where absorbed lipids enter.

What is the primary function of the large intestine?

The absorption of water from indigestible food residues.

What are haustral contractions?

Slow movements in the large intestine that mix and move fecal material.

What are goblet cells?

GI cells responsible for producing mucus in the intestines.

What is Helicobacter pylori?

A bacterium associated with the development of stomach ulcers.

What is celiac disease?

An autoimmune disorder that damages the villi and brush border of the small intestine.

What is the Basic Electrical Rhythm?

The term for the stomach's rhythmic contractions.

What is the cephalic phase?

The phase of gastric secretion that begins before food enters the stomach.

What is gastrin?

A hormone used as an example in GI regulation.

What are plicae circulares?

Circular folds in the small intestine that slow the movement of chyme to increase absorption.

What is the hepatic portal vein?

The blood vessel that carries nutrient-rich blood from the GI tract to the liver.

What are rugae?

Folds in the stomach lining that allow for expansion.

What is the pyloric valve?

The sphincter between the stomach and the duodenum.

What is the ileocecal valve?

The sphincter between the small intestine (ileum) and the large intestine (cecum).

What are teniae coli?

Three bands of longitudinal smooth muscle found in the large intestine.

What are chylomicrons?

The large packages of lipids that enter lacteals because they cannot fit into blood capillaries.

What is trypsin?

An enzyme that digests proteins in the small intestine.

What is pepsin?

The active enzyme that begins protein digestion in the stomach, activated by