This video provides information regarding the combined effect of Hypothalamus-pitutiary-thyroid gland. A defect at any level of the pathway can lead to thyroid hormone imbalance and alter the body's metabolism. Timeline: 0:00 introduction and function 0:45 release of hormones ( pathway) 1:40 TSH receptors 2:30 TSH mechanism 4:20 effect of T3 &T4