Mod 6 Ws

Module 06 Lab Worksheet: Digestive System

Introduction

This week’s lab will examine the various processes that occur within our digestion system including mechanical and chemical digestion.

Objectives

Objectives for this week’s lab include: 1) differentiating between mechanical and chemical digestion, 2) compare and contrast the various roles of the organs involved within the process of digestion, and 3) explain the importance of digestive enzymes in the process of digestion.

Overview

The digestive system is dependent on a number of processes, mainly mechanical and chemical digestion. Mechanical digestion is the process of breaking down the food we ingest into smaller pieces ultimately increasing the surface area. The food is not chemical changed. Chemical digestion is dependent upon digestive enzymes (specialized proteins) that will chemically change and break food down into its individual chemical components, such as amino acids, monosaccharaides, triglycerides, cholesterol, nucleic acids and vitamins. For example, we mechanically digest meat with our teeth and stomach acid. The meat is chemically digested and separated into individual amino acids by specific digestive enzymes found in the stomach and small intestine. Normally, digestive enzymes will have the suffix of “-ase” and be named after the nutrient it chemical digests. For example, the disaccharide sugar lactose (galactose-glucose) is chemically broken into the two monosaccharaides of galactose and glucose by the digestive enzyme lactase.

The gastrointestinal tract is a long tube that starts at our esophagus and ends at our anus. This tube is composed of four layers with the internal layer exposed to the food is called the mucosa. The mucosa has different characteristics and properties depending on the section of the digestive system. The mouth, esophagus, stomach, small intestine and large intestine compose the digestive system along with the accessory organs of the liver,...