Foundations
How hormones signal and how feedback loops work — the logic behind every endocrine drug.
How Hormones — and Endocrine Drugs — Work
The nervous system sends fast, private messages down wires. The endocrine system does the opposite: it releases chemical messengers into the blood that travel everywhere, yet act only on the cells built to hear them. Grasp how a hormone delivers its order — and why some act in seconds while others take days — and every endocrine drug in this whole section suddenly makes sense.
Feedback Loops: The Thermostat Behind Every Endocrine Drug
The body controls its hormones the way a thermostat controls a room: sense the level, and switch the heating off when there's enough. This single loop explains why giving a hormone as a drug can silence the patient's own gland, why stopping steroids suddenly is dangerous, and how a blood test can tell whether the problem lies in the gland or in the brain above it.
