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From Twiggy to Tubby

The Progression of Insulin Resistance and Type II Diabetes


Abigail R. Wilson
Division of Biology
Kansas State University
Ashley E. Rhodes
Division of Biology
Kansas State University
Timothy G. Rozell
Animal Sciences and Industry
Kansas State University


This case study explores the topics of diffusion, osmosis, membrane transport, and the physiological significance of glucose and insulin in the human body. The story begins with a high school athlete, Timmy, who is incredibly efficient at metabolizing carbohydrates for energy; this is where the reader is introduced to normal carbohydrate digestion and metabolism for energy within skeletal muscle cells. As Timmy enters college, he withdraws from sports and physical activity but continues to consume massive amounts of highly soluble carbohydrates, resulting in insulin resistance and ultimately type II diabetes. Throughout the case students are prompted with conceptual questions and interactive figures that require the application and transfer of information they have been introduced to. Originally written for intermediate and advanced physiology courses that cover foundational and complex concepts in science, the case is also appropriate for courses in intermediate biology, nutritional sciences, animal sciences, and exercise sciences.


  • Explain the processes required for digestion of carbohydrates as well as the process related to the absorption of carbohydrates.
  • Describe the fate of glucose once it's absorbed into circulation and how it relates to exercising skeletal muscle cells.
  • Diagram the absorption of glucose from the lumen of the small intestine, into the extracellular fluid, and finally into the blood.
  • Identify which transporters are necessary for glucose absorption from the lumen into circulation and how these transporters are regulated/affected after a meal.
  • Diagram glucose uptake from the blood into skeletal muscle cells.
  • Explain the importance of insulin and how this affects glucose uptake into skeletal muscle cells in a healthy state and then explain how insulin resistance and type II diabetes disrupt this process.
  • Hypothesize how Timmy's average blood glucose changes from when he was a healthy athlete to his development of insulin resistance.
  • Describe the difference between insulin resistance (IR) and type II diabetes.


insulin resistance; Type II diabetes; glucose; insulin; diffusion; osmosis; active transport; SGLT-1; GLUT2; skeletal muscle; digestion; absorption

Topical Areas


Educational Level

High school, Undergraduate lower division, Undergraduate upper division, Graduate, Professional (degree program), Clinical education, General public & informal education



Type / Methods




Subject Headings

Biology (General)  |   Cell Biology  |   Physiology  |   Medicine (General)  |   Sports Science  |   Biochemistry  |   Molecular Biology  |   Nutrition  |   Science (General)  |  

Date Posted


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