Study Notes
Digestion and absorption involve the breakdown of food into smaller components and their uptake into the body. The process occurs in the alimentary canal, with key roles played by various organs and enzymes.
- Oesophagus — A hollow tube connecting the oral cavity to the stomach, separated from the trachea by the epiglottis. Example: Food is moved in a bolus via peristalsis.
- Stomach — A temporary storage tank where food is mixed by churning and protein digestion begins. Example: Gastric pits release digestive juices creating an acidic environment.
- Small Intestine — A long, highly folded tube where nutrients are absorbed. Example: Consists of the duodenum, jejunum, and ileum.
- Large Intestine — The final section of the alimentary canal where water and minerals are absorbed. Example: Includes the colon and rectum.
- Salivary Glands — Release saliva to moisten food and contain enzymes like amylase. Example: Initiates starch breakdown.
- Pancreas — Produces enzymes released into the small intestine and secretes hormones. Example: Insulin and glucagon regulate blood sugar.
- Liver — Uses absorbed materials to make key chemicals and detoxifies substances. Example: Produces bile for fat emulsification.
- Gallbladder — Stores bile produced by the liver. Example: Releases bile into the small intestine via the bile duct.
- Peristalsis — Moves food through the alimentary canal by muscle contractions. Example: Mixes food with enzymes in the small intestine.
- Pancreatic Juice — Contains enzymes to digest macromolecules in food. Example: Amylase, lipases, and proteases.
- Villi — Increase the surface area for absorption in the small intestine. Example: Absorb monomers, mineral ions, and vitamins.
Exam Tips
Key Definitions to Remember
- Oesophagus: A tube connecting the oral cavity to the stomach.
- Peristalsis: Muscle contractions that move food through the alimentary canal.
- Villi: Structures that increase surface area for absorption in the small intestine.
Common Confusions
- Mixing up the roles of the small and large intestines.
- Confusing the functions of the pancreas and liver.
Typical Exam Questions
- What is the role of the stomach in digestion? The stomach stores food and begins protein digestion with its acidic environment.
- How does the small intestine absorb nutrients? Through villi that increase surface area and absorb monomers, ions, and vitamins.
- What enzymes are found in pancreatic juice? Amylase, lipases, and proteases.
What Examiners Usually Test
- Understanding of the digestive process and the role of different organs.
- The function and importance of enzymes in digestion.
- The absorption process in the small intestine and the role of villi.