
MCAT Basics (from MedSchoolCoach) The Digestive System
Dec 30, 2025
Dive into the fascinating world of the digestive system! Discover how food transforms into energy through mechanical and chemical digestion. Learn about the key roles of the stomach, small intestine, liver, and pancreas. Understand the processes of absorption and the hormonal regulation that keeps everything in sync. Explore the journey of nutrients as they travel through the GI tract and the significance of enzymes in breaking down food. Plus, tips for acing your MCAT await!
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Digestion Starts Before You Eat
- Digestion begins before ingestion via salivation and cephalic responses.
- Saliva lubricates, contains amylase to start starch breakdown, and defends orally.
Saliva Is Multifunctional
- Saliva is ~99% water but includes mucin, enzymes (amylase), lysozyme, and electrolytes.
- Salivary amylase hydrolyzes starch into di- and trisaccharides for later breakdown.
Peristalsis Drives Bolus Movement
- Peristalsis propels boluses via wave-like muscular contractions from esophagus through intestines.
- Think of squeezing toothpaste down a tube as an analogy.


