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๐ŸงฌAP Biology Review

QR code for AP Biology practice questions

Endocrine System

๐ŸงฌAP Biology
Review

Endocrine System

Written by the Fiveable Content Team โ€ข Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 examโ€ขWritten by the Fiveable Content Team โ€ข Last updated September 2025

Resources

In this session, we cover aspects of the endocrine system. We look at how hormones signal, and discuss the differences between the major feedback mechanisms (negative and positive feedback). In addition, we learn that the endocrine system regulates growth, metabolism, sexual development, and homeostasis to allow our bodies to thrive. Furthermore, we review positive and negative feedback examples, such as water level retention, calcium levels, menstruation, and blood sugar regulation. Positive feedback amplifies the stimulus (ex. labor process where the momโ€™s brain secretes oxytocin to allow for contractions, then the release of prostaglandins, and more oxytocin is secreted as the cycle continues), while negative feedback decreases the stimulus to maintain homeostasis (ex. if the bodyโ€™s temperature is high, blood vessels dilate and excess heat is sweated off). We end the session with a review of how hormones signal and great ways to study for the class.