Organs of the Alimentary Canal (in order)

1. Mouth

2. Oesophagus (Gullet)

3. Stomach

4. Liver

5. Gall Bladder

6. Pancreas

7. Small Intestine

8. Large Intestine

9. Rectum

10. Colon

11. Anus

Functions of Each Organ

1. Mouth

• Chews food and mixes it with saliva.

• Teeth crush food into smaller pieces.

• Saliva lubricates food, begins starch digestion, and makes swallowing easier.

• Tongue rolls food into a bolus and pushes it to the back of the mouth for swallowing.

2. Oesophagus (Gullet)

• Passage between the pharynx and stomach.

• Moves bolus to the stomach by peristalsis (wave-like muscular contractions).

3. Stomach

• Elastic bag that stores food temporarily.

• Mixes food with gastric juice and hydrochloric acid.

• Begins protein digestion (meat, beans).

• Absorbs simple substances like glucose and water.

• Hydrochloric acid kills germs entering with food.

4. Liver

• Large reddish-brown gland in the upper right abdomen.

• Secretes bile to aid fat digestion and absorption.

• Metabolizes proteins, carbohydrates, and fats.

• Synthesizes vitamin A and blood clotting substances.

• Detoxifies harmful substances.

• Breaks down worn-out red blood cells.

5. Gall Bladder

• Small muscular sac attached to the liver.

• Stores bile until needed for digestion.

6. Pancreas

• Large elongated gland behind the stomach.

• Secretes pancreatic juice containing enzymes (amylase, lipase, trypsinogen, chymotrypsinogen).

• Produces insulin to regulate blood sugar.

7. Small Intestine

• Long coiled tube where most digestion and absorption occur.

• Completes digestion of proteins, carbohydrates, and fats.

• Absorbs nutrients into the bloodstream through villi.

• Mixes food with intestinal juice.

8. Large Intestine

• Wider but shorter than the small intestine.

• Absorbs water and mineral salts.

• Forms semi-solid feces.

• Houses beneficial bacteria that produce vitamins like vitamin K.

9. Rectum

• Final section of the large intestine.

• Stores feces temporarily before elimination.

• Signals the urge to defecate when full.

10. Colon

• Main part of the large intestine (ascending, transverse, descending, sigmoid).

• Absorbs water and electrolytes.

• Compacts waste into feces.

• Site of bacterial fermentation of undigested carbohydrates.

11. Anus

• External opening at the end of the digestive tract.

• Controls release of feces through sphincter muscles.

• Ensures waste is expelled in a controlled manner.

Summary Flow

• Mouth → chewing and saliva action

• Oesophagus → peristalsis

• Stomach → protein digestion and germ-killing

• Liver & Gall Bladder → bile secretion and storage

• Pancreas → enzyme and insulin secretion

• Small Intestine → nutrient absorption

• Large Intestine & Colon → water absorption and feces formation

• Rectum & Anus → storage and elimination of waste

Tasks and Homework Revision

• Review the functions of each digestive organ and create flashcards for memorization.

• Draw and label a diagram of the digestive system.

• Write a short essay explaining the journey of food through the digestive system.

• Complete practice questions on digestion and absorption processes.

• Revise key terms such as peristalsis, bile, enzymes, and villi.

• Prepare for a quiz on the digestive system organs and their functions.