Final answer:
The mouth starts digestion mechanically and chemically, the oesophagus transports food to the stomach, where further digestion occurs. The hepatic and biliary system processes nutrients and aid in fat digestion. The small intestine is the primary site for nutrient absorption, and the large intestine handles water absorption and faeces formation.
Step-by-step explanation:
The student asked to distinguish the normal structure and function of the mouth, esophagus, stomach, hepatic and biliary system, and large and small intestines. Here's a detailed breakdown:
- Mouth: The mouth includes the lips, cheeks, palate, tongue, and teeth. It initiates digestion by mechanically breaking down food through chewing, while enzymes in the saliva start the chemical digestion of carbohydrates.
- Esophagus: A muscular tube that connects the mouth to the stomach. It serves as a conduit for food and beverages, moved through peristalsis, a series of wave-like muscle contractions.
- Stomach: A muscular organ that further breaks down food mechanically and chemically. It secretes gastric juices including hydrochloric acid and enzymes to initiate protein digestion.
- Hepatic and Biliary System: This system consists of the liver, gallbladder, and bile ducts. The liver processes nutrients absorbed from the small intestine and detoxifies chemicals. The gallbladder stores bile produced by the liver, and bile aids in the digestion and absorption of fats.
- Small Intestine: The major site for digestion of food and absorption of nutrients. It has three segments: the duodenum, jejunum, and ileum.
- Large Intestine: Comprises the colon, rectum, and anus. It absorbs water and electrolytes, forming and expelling feces.
By understanding the distinctive functions of these components, one can appreciate the complex process of digesting and absorbing nutrients that fuel the body.