Hypothalamus, anterior pituitary and thyroid

Thyroid axis (HPT) mnemonics

The body's thermostat and idle-speed dial.

The three tiers

TRH → TSH → T₃/T₄: hypothalamus, pituitary, thyroid

Reading the labs

Low T₄ with high TSH: thyroid's fault. Low T₄ with low TSH: look upstream.

A mnemonic only sticks once you have used it. The quiz and the rebuild below both draw on these exact steps.