TBL Module: Digestive System
revised 12.22.16
Learning Objectives
Understand why you have a digestive system. Understand the functions it performs and how these
are accomplished by the components of the digestive system.
Digestion is the breaking down of food substance into simpler molecules. As
thermodynamic machines, organisms must constantly expend energy to remain in an ordered
state. To do so our cells extract energy from the chemical bonds in our foodstuffs in a process
known as cellular respiration. As heterotrophs, we cannot produce our own foodstuffs and
therefore derive the materials for energy (and essential nutrients) from other organisms, either
directly or symbiotically. Since foodstuffs provided by other organisms rarely come in a form
utilizable by cells (i.e., simple molecules, e.g. Twinkies), some sort of digestion is necessary.
In small heterotrophs, where every cell is exposed to the environment, each cell can directly
obtain foodstuffs and digestion can be accomplished intracellularly. However, in large
heterotrophs, such as ourselves, not all cells are exposed to the environment and an
extracellular digestive system is required. Such digestive systems work in concert with the
circulatory and respiratory systems to deliver the molecules necessary for each cell’s survival.
Advance Assignment
Prior to coming to class, you must read the following:
Chapters 16, 17 and 18 in Ross and Pawlina, 7th ed.
Class lecture notes for Digestive System I, II and III
Be prepared to take a 10-question, multiple-choice Readiness Assessment Test (RAT) based
on the material in the class notes. However, be sure also to read the book chapters to enhance
your general understanding of the material and to provide a source of relevant diagrams, tables, and
micrographs, which you should consult when studying the class notes.
Required materials for Group Application Exercise
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Lecture notes for Digestive System I, II and III
Lab notes for Digestive System I, II and III
Text book (copy provided; see below concerning electronic versions)
Stedman's or Dorland's Medical Dictionary (one copy provided)
Merck Manual of Diagnosis and Therapy (copies provided)
DiFiore’s Atlas (one copy provided)
Electronic devices: During the TBL application exercise computer use is limited to
accessing only the electronic version of the course textbook. Hard copies of the
textbook are provided. No other resources (either on the hard drive or via the
internet) can be accessed using your computer. No other electronic devices (e.g.,
cell phones, PDAs, cameras, etc.) other than a calculator are permitted.