Human Digestive System – Key Structures and Functions

Vocabulary flashcards summarizing the major organs, sphincters, and processes of the human digestive system, along with their primary functions.

Mouth

Chews and mixes food with saliva; the first step of ingestion.

Pharynx

Directs food from the mouth to the esophagus.

Salivary glands

Secrete saliva to moisten food and begin digestion.

Epiglottis

Cartilaginous flap that protects airways during swallowing.

Upper esophageal sphincter

Muscular ring allowing food to pass from mouth to esophagus and preventing backflow.

Esophagus

Muscular tube that moves food from the mouth to the stomach.

Lower esophageal (cardiac) sphincter

Valve that allows passage from esophagus to stomach and prevents stomach acid from re-entering the esophagus.

Trachea

Windpipe that allows air to pass to and from the lungs (not part of digestion but adjacent to the pharynx).

Diaphragm

Muscle sheet that separates the thoracic and abdominal cavities.

Stomach

Churns, mixes, and grinds food to a liquid; adds acid, enzymes, and fluid.

Pyloric sphincter

Valve controlling flow from stomach to small intestine and preventing backflow.

Liver

Manufactures bile salts that emulsify fats for digestion.

Gallbladder

Stores and concentrates bile until needed for fat digestion.

Bile duct

Channel that conducts bile from gallbladder to the small intestine.

Pancreas

Produces digestive enzymes and bicarbonate to neutralize acid chyme entering the small intestine.

Pancreatic duct

Conveys pancreatic juice from the pancreas to the small intestine.

Small intestine (duodenum, jejunum, ileum)

Secretes enzymes to digest all energy-yielding nutrients; absorbs nutrients into blood and lymph.

Ileocecal valve (sphincter)

Controls passage from small to large intestine and prevents backflow.

Large intestine (colon)

Absorbs water and minerals; moves waste (fiber, bacteria, unabsorbed nutrients) to the rectum.

Appendix

Pouch that houses beneficial bacteria and lymph cells.

Rectum

Stores waste prior to elimination.

Anus

Holds rectum closed and opens to allow elimination of feces.

Ingestion

General term for taking food into the body via the mouth.

Elimination

Expulsion of waste materials from the digestive tract through the rectum and anus.

Mouth

Chews and mixes food with saliva; the first step of ingestion.

Pharynx

Directs food from the mouth to the esophagus.

Salivary glands

Secrete saliva to moisten food and begin digestion.

Epiglottis

Cartilaginous flap that protects airways during swallowing.

Upper esophageal sphincter

Muscular ring allowing food to pass from mouth to esophagus and preventing backflow.

Esophagus

Muscular tube that moves food from the mouth to the stomach.

Lower esophageal (cardiac) sphincter

Valve that allows passage from esophagus to stomach and prevents stomach acid from re-entering the esophagus.

Trachea

Windpipe that allows air to pass to and from the lungs (not part of digestion but adjacent to the pharynx).

Diaphragm

Muscle sheet that separates the thoracic and abdominal cavities.

Stomach

Churns, mixes, and grinds food to a liquid; adds acid, enzymes, and fluid.

Pyloric sphincter

Valve controlling flow from stomach to small intestine and preventing backflow.

Liver

Manufactures bile salts that emulsify fats for digestion.

Gallbladder

Stores and concentrates bile until needed for fat digestion.

Bile duct

Channel that conducts bile from gallbladder to the small intestine.

Pancreas

Produces digestive enzymes and bicarbonate to neutralize acid chyme entering the small intestine.

Pancreatic duct

Conveys pancreatic juice from the pancreas to the small intestine.

Small intestine (duodenum, jejunum, ileum)

Secretes enzymes to digest all energy-yielding nutrients; absorbs nutrients into blood and lymph.

Ileocecal valve (sphincter)

Controls passage from small to large intestine and prevents backflow.

Large intestine (colon)

Absorbs water and minerals; moves waste (fiber, bacteria, unabsorbed nutrients) to the rectum.

Appendix

Pouch that houses beneficial bacteria and lymph cells.

Rectum

Stores waste prior to elimination.

Anus

Holds rectum closed and opens to allow elimination of feces.

Ingestion

General term for taking food into the body via the mouth.

Elimination

Expulsion of waste materials from the digestive tract through the rectum and anus.

What is the order of the digestive process?

The general order of organs in the digestive process is:

1. Mouth
2. Pharynx
3. Esophagus
4. Stomach
5. Small Intestine (duodenum, jejunum, ileum)
6. Large Intestine (colon)
7. Rectum
8. Anus