Intro to the Digestive System Lecture Flashcards

This set of vocabulary flashcards covers the anatomy and physiology of the human digestive system, including the functions of organs, types of digestion, and key enzymes involved in the process.

Herbivores

Animals that eat mainly plants, such as gorillas, cows, rabbits, and snails.

Carnivores

Animals that eat other animals, such as sharks, hawks, spiders, and snakes.

Omnivores

Animals that eat both animals and plants, such as cockroaches, bears, raccoons, and humans.

Digestion

The breakdown of large, complex organic molecules into smaller components that can be used by the body and diffuse across plasma membranes.

Ingestion

The consumption of or taking in of nutrients.

Absorption

The transport or delivery of digested nutrients to body tissues; most of this occurs in the small intestine.

Egestion

The elimination of food waste materials from the body.

Mechanical Digestion

The physical breakdown of food, such as teeth grinding or smooth muscle contractions in the stomach and small intestine, to increase surface area.

Chemical Digestion

The process where enzymes released from glands break down foods into smaller subunits small enough to be absorbed.

Amylase

An enzyme found in saliva and produced by the pancreas that digests starch.

Mucus

A substance that protects the soft lining of the digestive system and lubricates food for easier swallowing.

Bolus

A lubricated ball of food formed in the oral cavity that is pushed by the tongue to the back of the throat to be swallowed.

Epiglottis

A flap of cartilage that closes the trachea (windpipe) when swallowing to ensure food travels into the esophagus.

Peristalsis

Wave-like muscular contractions that propel food through the esophagus and the entire gastrointestinal tract.

Esophageal sphincter

Rings of muscle where the esophagus attaches to the stomach that control the release of food into the stomach.

Stomach Gastric Fluids

Substances secreted by millions of cells lining the stomach consisting of mucus, hydrochloric acid ($HCl$), pepsinogens, and other substances.

Pepsin

An enzyme used by the stomach to digest protein.

Chyme

The name for partially digested food that is released from the stomach into the small intestine.

Pyloric sphincter

A muscular valve located at the bottom of the stomach that slowly releases chyme into the small intestine.

Stomach Ulcer

A lesion in the lining of the stomach occurring when the protective mucus lining breaks down, often linked to the bacterium Heliobacter pylori.

Endoscope

A tool used to view the internal digestive tract, such as stomach ulcers or tumors, and to extract tissue for a biopsy.

Duodenum

The first section of the small intestine where most chemical digestion occurs and where bile and pancreatic enzymes enter.

Villi

Millions of small finger-like projections lining the small intestine that increase surface area for the absorption of nutrients.

Large Intestine (Colon)

A $1.5\,m$ long organ that re-absorbs water (more than $90\%$), inorganic salts, minerals, and vitamins from waste products.

Trypsin and Chymotrypsin

Digestive enzymes produced by the pancreas to digest proteins in the small intestine.

Lipase

An enzyme produced by the pancreas to digest lipids (fats).

Bicarbonate ion

A solution released by the pancreas into the small intestine to neutralize acidic chyme, raising the $pH$ from $2.5$ to $9.0$.

Bile

A fluid produced by the liver and stored in the gall bladder that emulsifies fats, breaking big globules into smaller ones.

Rectum

The last section of the large intestine where feces, composed of undigested materials like cellulose and bacteria, are eliminated.

Appendix

A vestigial organ located near the junction of the small and large intestines.