Lesson 4 - The Alimentary Canal

Question 1

Name organs/sections of the human alimentary canal in order

Answer 1

Mouth, esophagus, stomach, duodenum, ileum, colon, rectum, anus

Question 2

What is the function of:
Mouth?

Answer 2

• Ingestion
• Mechanical digestion of food due to crushing action of the teeth
• Chemical digestion of starch by salivary amylase.

Question 3

Esophagus?

Answer 3

Carriage of food to stomach via peristalsis

Question 4

Stomach?

Answer 4

• Contraction of stomach muscles to churn up food
• Secretion of hydrochloride acid
• Chemical digestion of proteins my enzymes

Question 5

Ileum?

Answer 5

• Site of chemical digestion of carbohydrates, fats and proteins
• Receives pancreatic juice and bile

Question 6

Duodenum?

Answer 6

• Chemical digestion of carbohydrates, fats and proteins by enzymes
• Absorption of digested food

Question 7

Colon?

Answer 7

Absorption of water

Question 8

Rectum?

Answer 8

Storage of faeces

Question 9

Anus?

Answer 9

Site of egestion

Question 10

Name layers of the mammalian gut wall

Answer 10

Serosa, Muscularis, Submucosa, Mucosa

Question 11

What is the serosa?

Answer 11

• Contains tough connective tissue which protects the gut wall
• Helps reduce friction with other abdominal organs during peristalsis

Question 12

What is the muscularis?

Answer 12

Make coordinated waves of contractions and relaxations (peristalsis), pushing the ball (bolus) of food along the alimentary canal.

Question 13

What is the submucosa?

Answer 13

• Consists of connective tissue containing blood and lymph vessels which remove the absorbed products of digestion.
• Contains the nerves which coordinate peristalsis.

Question 14

What is the mucosa?

Answer 14

• The epithelium secretes mucus which lubricates and protects the mucosa.
• In some regions of the gut, it secretes digestive juices and in others, it absorbs digested food.