BI 231 - Human Physiology and Anatomy
Endocrine System Study Guide

Compiled by Pat Bowne, Linda Cram, Sherry Dollhopf,and Justin LaManna, 2007-11


The body controls cell function by sending hormones through the blood. Hormones act like neurotransmitters, attaching to receptors on the cell surface and using second-messenger systems to turn enzymes inside the cell on or off. They are vital links in the negative feedback loops that keep your body in balance. Since the control centers for most of these loops are in the brain, it makes sense for the brain to be able to control hormone release. This is done by the hypothalamus and pituitary.

Before class, make sure you: Can explain the steps of a second messenger system ( see neurotransmitter tutorial at

Can sketch and label the anatomy of the hypothalamus and pituitary
Tutorials and reading assignment: Review the endocrine system by doing the thyroid, CRH, and adrenal cortex tutorials at:
You may also use the thyroid tutorial at

Chapter 11

Chapter 19  pp 677-681, 685-696

What you should know for the assessment:

--Be able to describe how the hypothalamus and pituitary control endocrine glands

-- Know the differences between releasing hormones and trophic hormones. Also, you should be able to predict how the levels of releasing and trophic hormones will change if an endocrine gland produces too much or too little hormone

--Be able to explain the structure and function of the thyroid gland as well as the function of thyroid hormones T3 and T4

--Also, be able to explain the negative feedback system controlling the release of thyroid hormone and the importance of Iodine in the production of thyroid hormone

--Be able to explain what happens if T3 and T4 levels increase --DIAGNOSE different thyroid imbalances, determining which part of the hypothalamo-pituitary-thyroid axis is malfunctioning

--What is a goiter and what is the most common cause?

--Know how PTH and Thyrocalcitonin regulate blood Calcium

--What is ADH, how is it produced and regulated, and what does it do?

--Be able to describe the control and release of cortisol in the CRH pathway

Endocrine terms to know
Practice Questions

--Three men are suffering from low blood glucose, and the doctor has narrowed it down to an adrenal cortex problem in each case. From the additional data below, explain which organ is most likely damaged in each man.

Mr. A has high blood pressure and hypokalemia. His ACTH levels are elevated.

Mr. B has low ACTH levels, and when he is injected with CRH it has no effect.

Mr. C has low ACTH levels, but an injection of CRH causes his blood glucose and ACTH to return to normal.

--A man has a disease in which his hypothalamus has no receptors for hormones; therefore, it cannot detect hormones in his blood. What are the THREE most serious problems you expect this man to have as a result?

--PREDICT how trophic hormone levels will change if cortisol production is abnormal

Practice question with example answer

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