Digestion and Absorption- Module 3

Flashcards covering key vocabulary terms related to digestion and absorption, primary and accessory organs, digestive processes, and common GI conditions.

Digestion

The process of breaking down food into smaller compounds, primarily occurring in the small intestine.

Absorption

The process where nutrients cross the lining of the intestine to enter the circulatory system.

Gastrointestinal (GI) tract

A series of organs with outer layers of muscles and an inner mucosal layer, where digestion occurs.

Primary Organs of the GI Tract

Mouth, Esophagus, Stomach, Small Intestine, Large Intestine, Rectum.

Accessory Organs of the GI Tract

Salivary glands, Liver, Pancreas, Gallbladder.

Transit time

The period of time it takes food to travel the length of the digestion tract.

Mechanical Digestion

Physical processes like chewing, grinding, mixing, and peristalsis.

Chemical Digestion

Breakdown of large food compounds into smaller units for absorption using secretions and enzymes.

Peristalsis

Wavelike muscular movements that move food through the GI tract.

Taste sensations

Sweet, Salty, Sour, Bitter, Umami.

Epiglottis

A flap that closes to avoid choking by preventing food from entering the trachea.

Bolus

A mass of swallowed food moving through the esophagus.

Sphincter

Circular muscles that separate organs of the GI tract, acting as one-way doors to prevent food from flowing backwards.

Lower esophageal sphincter (LES)

A primary sphincter that separates the esophagus from the stomach.

Pyloric sphincter

A primary sphincter that separates the stomach from the small intestine.

Ileocecal valve

A primary sphincter that separates the ileum (small intestine) from the cecum (large intestine).

Chyme

Liquified food mixed with digestive juices in the stomach.

Gastric juices

Secretions in the stomach including Hydrochloric acid, Mucus, Pepsinogen, and Gastrin.

Hydrochloric acid (HCl)

Denatures proteins, liquifies food, activates pepsin and lingual lipase, helps iron absorption, and neutralizes bacteria in the stomach.

Mucus (stomach)

Protects the lining of the stomach from hydrochloric acid.

Intrinsic factor

Essential for the absorption of Vitamin B12; deficiencies can cause pernicious anemia.

Pepsinogen

A proenzyme in gastric juice that converts to active pepsin by stomach acid for protein digestion.

Gastrin

A hormone that controls movement of the stomach and HCl secretion, and communicates with other digestive organs.

Small Intestine

The primary site of digestion and absorption, consisting of the duodenum, jejunum, and ileum.

Villi

Small intestinal projections (folds) that line the small intestine to assist in nutrient absorption.

Microvilli

Tiny hairs that cover each villus and extend into the lumen, secreting digestive enzymes and trapping nutrient molecules.

Pancreas

An accessory organ that secretes bicarbonate to neutralize acidic chyme and enzymes that act on macronutrients.

Bicarbonate (pancreatic)

Neutralizes acidic chyme from the stomach in the small intestine.

Liver

An accessory organ responsible for producing bile.

Gallbladder

An accessory organ that stores and releases bile to assist in fat digestion.

Bile

A substance produced by the liver and stored in the gallbladder, which emulsifies fat to aid in digestion.

Capillaries

Small blood vessels that carry water-soluble nutrients from the intestinal wall to the liver.

Lacteals

Lymphatic vessels that absorb fat and fat-soluble substances from the small intestine, which then travel through the lymph system.

Salivary amylase

An enzyme in the mouth that begins the breakdown of carbohydrates.

Pancreatic amylase

An enzyme in the small intestine that breaks down carbohydrates into smaller glucose chains.

Monosaccharides

Simple sugars (glucose, galactose, and fructose) that are absorbed after carbohydrate digestion.

Lipase

An enzyme that breaks down fat into fatty acids and monoglycerides.

Micelles

Structures formed by monoglycerides and fatty acids that aid in their absorption through villi.

Chylomicron

A lipoprotein formed from longer chain fatty acids and triglycerides, which is absorbed into the lymphatic system.

Gut microbiota

Approximately 100 trillion bacteria, viruses, fungi, and other microorganisms residing in the large intestine.

Prebiotics

Non-digestible carbohydrate sources that feed probiotics, supporting their metabolism in the large intestine.

Probiotics

Live microorganisms that can have a beneficial effect on health, found in foods like yogurt.

Synbiotics

Combinations of prebiotics and probiotics for enhanced health benefits.

Constipation

A GI condition characterized by infrequent or difficult stool movement, often improved by fiber, water, and exercise.

Gastroesophageal Reflux Disease (GERD)

Also known as heartburn, it is pain from stomach acid backing into the esophagus, often related to being overweight, pregnancy, or eating habits.

Peptic Ulcer Disease

A lesion in the lining of the stomach or duodenum, most commonly caused by Heliobacter pylori (H. pylori).

Heliobacter pylori (H. pylori)

The most common bacterial cause of peptic ulcers, transmitted via oral-oral and fecal-oral exposure.