Flow Chart: Human Digestive System
- Mouth
- Ingestion of food.
- Teeth chew food (Mechanical digestion).
- Salivary glands release saliva.
- Saliva contains enzyme salivary amylase (begins starch digestion).
- Pharynx and Esophagus
- Pharynx connects mouth to esophagus.
- Esophagus pushes food to the stomach using peristaltic movement.
- Stomach
- Food is mixed with gastric juices.
- Gastric juice contains:
- HCl (Hydrochloric acid) – kills bacteria, creates acidic medium.
- Pepsin enzyme – begins protein digestion.
- Food turns into semi-liquid chyme.
- Small Intestine (Duodenum → Jejunum → Ileum)
- Major site for digestion & absorption.
- Receives:
- Bile juice from liver (via gall bladder) – emulsifies fats.
- Pancreatic juice from pancreas – contains enzymes:
- Amylase (digests starch)
- Trypsin (digests proteins)
- Lipase (digests fats)
- Intestinal juice completes digestion.
- Villi absorb nutrients into the bloodstream.
- Large Intestine (Colon)
- Absorbs excess water and minerals.
- Undigested food is converted into semi-solid waste.
- Rectum
- Stores feces temporarily.
- Anus
- Egestion – removal of undigested waste (defecation).
Key Enzymes & Their Functions
| Enzyme | Source | Function |
|---|---|---|
| Salivary Amylase | Salivary Glands | Converts starch → maltose |
| Pepsin | Stomach (gastric juice) | Digests proteins |
| Bile (not enzyme) | Liver (stored in gall bladder) | Emulsifies fats (breaks into droplets) |
| Pancreatic Amylase | Pancreas | Digests starch |
| Trypsin | Pancreas | Digests proteins |
| Lipase | Pancreas | Digests fats |