Cheat Sheet 15: Digestive System

Mouth

Initial digestion site; chews food and mixes with saliva.

Esophagus

Connects mouth to stomach; transports food via peristalsis.

Small Intestine

Primary site for digestion and nutrient absorption.

Pharynx

Throat area where food and air passages cross.

Stomach

Secretes gastric juice; digests food into chyme.

Bolus

Chewed food mixed with saliva before swallowing.

Pyloric Sphincter

Regulates food entry from stomach to small intestine.

Villi

Projections in small intestine that increase absorption area.

Microvilli

Tiny projections on villi; further increase absorption surface.

Gastric Juice

Contains digestive enzymes and HCl for food breakdown.

Chyme

Creamy mass of digested food from stomach.

Mucus Cells

Secrete mucus to protect stomach lining.

Parietal Cells

Secrete HCl to aid in digestion.

Chief Cells

Produce pepsinogen, activated to pepsin in stomach.

G Cells

Secrete gastrin to stimulate stomach acid secretion.

Duodenum

First segment of small intestine; major digestion site.

Jejunum

Middle segment; primary site for nutrient absorption.

Ileum

Final segment; absorbs nutrients and contains Peyer's patches.

Large Intestine

Absorbs water and electrolytes; prepares waste for excretion.

Ileocecal Valve

Controls food passage from small to large intestine.

Symbiotic Bacteria

Aid digestion and produce vitamins K and B12.

Liver

Produces bile; emulsifies fats for digestion.

Pancreas

Secretes digestive enzymes and bicarbonate into duodenum.

Bile

Emulsifies fats; produced in liver, stored in gallbladder.

Trypsin

Digestive enzyme that breaks down proteins.

Lipase

Enzyme that digests lipids (fats).

Amylase

Enzyme that digests carbohydrates.

Nucleases

Enzymes that digest nucleic acids.

Zymogens

Inactive digestive enzymes activated in small intestine.

Biliary Flow

Pathway for bile from liver to duodenum.

Digestive Enzyme Flow

Pathway of enzymes from pancreas to duodenum.