[02] Digestion and Absorption

Question 1

Where does carbohydrate digestion start and what enzyme initiates it?

Answer 1

Starts in the mouth with the enzyme amylase

Question 2

Where does protein digestion start and what enzyme initiates it?

Answer 2

Starts in the stomach with the enzyme pepsin

Question 3

Where does fat digestion occur and what substance aids it?

Answer 3

Occurs in the small intestine with the aid of bile

Question 4

What happens during the process of absorption in the digestive system?

Answer 4

Nutrients from digested food are taken into the bloodstream

Question 5

Where does the majority of nutrient absorption occur in the digestive system?

Answer 5

Small intestine

Question 6

What are the three parts of the small intestine and their roles in digestion and absorption?

Answer 6

• Duodenum → receives chyme from the stomach, and digestive juices from the liver and pancreas
• Jejunum → most of the nutrients are absorbed here
• Ileum → absorbs vitamin B12, bile salts, and any leftover nutrients

Question 7

How do villi and microvilli aid in absorption?

Answer 7

They increase the surface area of the small intestine, allowing for greater nutrient absorption

Question 8

What are the primary nutrients absorbed in the small intestine?

Answer 8

• Sugars (from carbohydrates)
• Amino acids (from proteins)
• Fatty acids and glycerol (from fats)

Question 9

What is absorbed in the large intestine?

Answer 9

• Water
• Electrolytes
• Vitamins produced by intestinal bacteria

Question 10

How is glucose absorbed into the bloodstream?

Answer 10

Via active transport through the intestinal epithelial cells

Question 11

How are amino acids absorbed?

Answer 11

Through active transport into the intestinal epithelial cells, then into the bloodstream

Question 12

How are fatty acids and glycerol absorbed?

Answer 12

They combine to form micelles, which diffuse into intestinal epithelial cells. They’re reassembled as triglycerides, packaged into chylomicrons, and enter the lymphatic system.

Question 13

What role does the pancreas play in digestion and absorption?

Answer 13

Produces and secretes digestive enzymes into the small intestine to break down macronutrients for absorption

Question 14

What role does the liver play in digestion and absorption?

Answer 14

Produces bile that emulsifies fats, aiding their digestion and absorption in the small intestine