A Case Study in Negative Feedback Regulation
Texas Tech University
In this interrupted case study, students shadow an endocrinologist as she tries to determine what is wrong with Angela Barber. Angela is a middle-aged woman presenting with symptoms suggestive of a thyroid issue. Students are given background information, patient history, and results from thyroid-specific blood tests. The exercise emphasizes the hypothalamic-pituitary-thyroid axis and particularly highlights the role of negative feedback. Students will use results from serum thyrotropin and thyroid hormone level tests, as well as patient symptoms, to come up with a diagnosis. In preparation for the diagnosis, students are asked to compare the endocrine profiles of patients with Graves' disease, Hashimoto's disease, iodine deficiency (primary hypothyroidism), and various tumors. The case was developed for college-level biology majors in a physiology course, but also has been used successfully for pre-nursing students in a non-majors anatomy and physiology course. Thus, this activity would be suitable for majors in physiology or pre-medical students, as well as allied health majors.
- Diagram the negative feedback system of the hypothalamic-pituitary-thyroid axis.
- Compare and contrast hyperthyroidism and hypothyroidism.
- Explain potential causes of a goiter.
- Compare different thyroid disorders and explain how dysregulation at various levels of the HPT axis correspond to each disorder.
Keywordsthyroid, thytopin, iodine, hyperthyroidism, feedback, Graves’ disease, iodine deficiency, hypothyroidism, HPT, Hashimoto’s disease, endocrinology
Educational LevelUndergraduate lower division, Undergraduate upper division
Type / MethodsDirected, Interrupted
Subject HeadingsBiology (General) | Medicine (General) | Nursing | Physiology | Science (General) |