The Mammalian Digestive System

Question 1

Digestion

Outline the 5 major stages of digestion and identify the primary location of each stage

Answer 1

• Ingestion: Occurs in the mouth, where food is taken in and mechanically broken down through chewing.
• Mechanical and Chemical Digestion: Takes place in the stomach, where food undergoes mechanical churning and mixing with gastric juices.
• Chemical Digestion and Absorption: Continues in the small intestine, where enzymes from the pancreas and bile from the liver break down nutrients into absorbable forms.
• Absorption: Primarily occurs in the small intestine, where nutrients are absorbed into the bloodstream or lymphatic system for distribution to cells throughout the body.
• Compaction and Elimination: Occurs in the large intestine, where water and electrolytes are absorbed, and undigested materials are compacted into feces for elimination through the anus.

Question 2

Digestion

Explain the difference between excretion and egestion

Answer 2

Excretion involves the removal of metabolic waste products from the body, such as urea, through various elimination pathways like urine and sweat. Egestion, on the other hand, refers to the expulsion of undigested food materials from the digestive tract via defecation, completing the digestive process.

Question 3

Digestive system

Think of a labbeled digestive system

Answer 3

Question 4

Digestive system

what are three ways the small intestine has adapted to carry out its function

Answer 4

1. Surface Area Increase: Extensive folding and villi/microvilli formations amplify surface area.
2. Specialized Cells: Epithelial cells feature microvilli for enhanced absorption and transport proteins.
3. Rich Blood Supply: Abundant capillaries and lacteals ensure efficient nutrient transport to the bloodstream.

Question 5

Digestion

Discuss the role of enzymes in the mammalian digestive system

Answer 5

1. Salivary Amylase: Breaks down carbohydrates (starches) into simpler sugars like maltose and glucose.
2. Pepsin: Digests proteins into smaller peptides.
3. Trypsin: Continues protein digestion, breaking down peptides into smaller peptides and amino acids.
4. Pancreatic Lipase: Breaks down fats (lipids) into fatty acids and glycerol.
5. Lactase, Sucrase, Maltase: Break down disaccharides (lactose, sucrose, and maltose) into monosaccharides (glucose, fructose, and galactose), respectively.

Question 6

Digestion

Compare mechanical and chemical digestion

Answer 6