Functions of Human Digestive Organs

Organ Major functions Other functions
Mouth
  •  Ingests food
  • Chews and mixes food
  • Begins chemical breakdown of carbohydrates
  • Moves food into the pharynx
  • Begins breakdown of lipids via lingual lipase
  •  Moistens and dissolves food, allowing you to taste it
  • Cleans and lubricates the teeth and oral cavity
  •  Has some antimicrobial activity
Pharynx
  •  Propels food from the oral cavity to the esophagus
  •  Lubricates food and passageways
Esophagus
  •  Propels food to the stomach
  •  Lubricates food and passageways
Stomach
  • Mixes and churns food with gastric juices to form chyme
  •   Begins chemical breakdown of proteins
  •  Releases food into the duodenum as chyme
  • Absorbs some fat-soluble substances (for example, alcohol, aspirin)
  •  Possesses antimicrobial functions
  •  Stimulates protein-digesting enzymes
  •   Secretes intrinsic factor required for vitamin B12 absorption in small intestine
Small intestine
  • Mixes chyme with digestive juices
  •  Propels food at a rate slow enough for digestion and absorption
  •  Absorbs breakdown products of carbohydrates, proteins, lipids, and nucleic acids, along with vitamins, minerals, and water
  • Performs physical digestion via segmentation
  •  Provides optimal medium for enzymatic activity
Accessory organs
  • Liver: produces bile salts, which emulsify lipids, aiding their digestion and absorption
  • Gallbladder: stores, concentrates, and releases bile
  •  Pancreas: produces digestive enzymes and bicarbonate
  •  Bicarbonate-rich pancreatic juices help neutralize acidic chyme and provide optimal environment for enzymatic activity
Large intestine
  •  Further breaks down food residues
  • Absorbs most residual water, electrolytes, and vitamins produced by enteric bacteria
  • Propels feces toward rectum
  •  Eliminates feces
  • ¬∑Food residue is concentrated and temporarily stored prior to defecation
  • Mucus eases passage of feces through colon

Binod G C

I'm Binod G C (MSc), a PhD candidate in cell and molecular biology who works as a biology educator and enjoys scientific blogging. My proclivity for blogging is intended to make notes and study materials more accessible to students.

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