Lesson · A.3.2
The endocrine system
How the HESI A2 tests the endocrine system: the major glands, their hormones, and the feedback loops that keep the body in balance.
ObjectiveA.3.2Read6 minExam weightRegulation and Control ≈ 16% of Anatomy & Physiology
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- Match each major endocrine gland to the hormones it secretes and the target tissue those hormones act on.
- Explain negative feedback with a worked example, such as the thyroid or blood glucose loop.
- Tell steroid and nonsteroid hormone signalling apart and say why the distinction matters for onset of action.
What the lesson concludes
- The endocrine system signals with hormones carried in the blood, so its effects are slower and longer lasting than nerve signals.
- The anterior pituitary is the master gland because most of its hormones are tropic, meaning they switch on other glands rather than acting directly.
- Negative feedback is the default control pattern: a rising hormone or metabolite level suppresses the signal that triggered its release.
- The adrenal cortex and adrenal medulla are two different tissues with two different hormone sets, a common trap in HESI items.
- The pancreas is both an exocrine and an endocrine gland, and its islet cells set blood glucose through two opposing hormones.