Eating Disorders and the Digestive System

Comprehensive vocabulary flashcards covering eating disorders, cellular respiration, ATP energetics, macronutrient synthesis, enzymatic digestion, circulatory capillary exchange, and gastric pathologies such as peptic ulcers.

Anorexia Nervosa

A severe eating disorder characterized by extreme food restriction, emaciation, an intense fear of gaining weight, and distorted body image; it carries a risk of death $6$ times higher than average and has the highest mortality rate of any mental disorder.

Bulimia Nervosa

An eating disorder marked by recurrent episodes of binge-eating unusually large amounts of food followed by compensatory behaviors such as forced vomiting, laxative abuse, fasting, or excessive exercise, while typically maintaining a relatively normal body weight.

Binge-Eating Disorder

The most common eating disorder in the United States, characterized by recurrent episodes of losing control over eating unusually large quantities of food without subsequent purging, fasting, or excessive exercise, often leading to being overweight or obese.

Gastric Fluid

Highly acidic fluid produced by the stomach (pH between $1$ and $2$) that, when brought up during recurrent vomiting in bulimia, severely erodes tooth enamel and alters tooth morphology.

Cellular Respiration

The metabolic process occurring in the mitochondria by which the chemical energy of glucose is converted into usable cellular energy in the form of $\text{ATP}$: $\text{C}_6\text{H}_{12}\text{O}_6 + \text{O}_2 + \text{ADP} + \text{P} \rightarrow \text{ATP} + \text{CO}_2 + \text{H}_2\text{O}$.

Adenosine Tri-Phosphate ($\text{ATP}$)

A high-energy molecule containing three phosphate groups that acts as the cell's usable energy currency—analogous to a fully charged battery—powering muscle contraction, nerve signaling, tissue building and repair, and temperature maintenance.

Adenosine Di-Phosphate ($\text{ADP}$)

A lower-energy molecule containing two phosphate groups—analogous to a depleted battery—formed when $\text{ATP}$ releases a phosphate group to provide energy for cellular work, which must be recharged by cellular respiration.

Mitochondria

Membrane-bound cellular organelles found in all human cells that serve as the site for cellular respiration and the synthesis of $\text{ATP}$.

Proteins

Nutrient macromolecules consisting of linear chains of amino acids linked by peptide bonds that fold into complex three-dimensional structures; humans contain approximately $2\text{ million}$ different types.

Triglycerides

High-energy fat molecules composed of one glycerol molecule bonded to three fatty acids that provide long-term energy storage in the body.

Maltose

A disaccharide ($\text{C}_{12}\text{H}_{22}\text{O}_{11}$) formed when two glucose monosaccharides ($\text{C}_6\text{H}_{12}\text{O}_6$) are bound together through condensation synthesis.

Starch

A complex plant energy-storage polysaccharide made of many joined glucose units that is readily digested by human enzymes into individual glucose molecules to fuel cellular respiration.

Cellulose

A complex structural polysaccharide found in plant cell walls that cannot be digested by humans because they lack the necessary enzyme, passing through the digestive tract undigested as fiber.

Salivary Amylase

A digestive enzyme secreted by the salivary glands into the mouth that initiates carbohydrate breakdown by converting some starch into the disaccharide maltose.

Pepsin

A protein-digesting enzyme secreted by gastric glands alongside hydrochloric acid ($\text{HCl}$) in the stomach that converts intact proteins into shorter polypeptides.

Trypsin

A digestive enzyme secreted by the pancreas into the small intestine that converts remaining dietary proteins into shorter polypeptides.

Peptidase

An enzyme produced by the small intestine that breaks down short polypeptides into individual amino acids for absorption.

Bile

A secretion produced by the liver that enters the small intestine to physically emulsify large fat globules into smaller fat droplets.

Lipase

A fat-digesting enzyme secreted by the pancreas that chemically converts emulsified fat droplets into absorbable fatty acids and glycerol.

Villi

Small projections lining the walls of the small intestine that absorb digested nutrient molecules (amino acids, glucose, and fatty acids) into the blood.

Hepatic Portal Vein

The specialized blood vessel that routes absorbed food molecules from the small intestine directly through the liver before they enter general circulation.

Capillaries

Microscopic blood vessels servicing body tissues where oxygen, amino acids, and glucose exit into cells at the arterial end, while carbon dioxide, wastes, and water enter the blood at the venous end.

Acid Reflux

A condition occurring when the lower esophageal sphincter relaxes improperly, allowing stomach acid to flow upward into the esophagus and causing heartburn; frequent reflux can develop into gastroesophageal reflux disease (GERD).

Peptic Ulcers

Open sores that develop on the interior mucosal lining of the esophagus, stomach, or upper small intestine (duodenum) as a consequence of stomach acid erosion.

Helicobacter pylori

A species of flagellated bacteria that infects the stomach, breaks down the protective mucus layer lining the gastric wall, and allows stomach acid to form peptic ulcers.

Dr. Barry Marshall

The medical researcher awarded the Nobel Prize for discovering that peptic ulcers are caused by the bacterium Helicobacter pylori rather than stress or spicy foods.