Patient suffering from hypothyroidism shows increased level of TSH. Why?

Question

Give scientific reason :

Patient suffering from hypothyroidism shows increased level of TSH. Why?

Answer 1

1. Hypothyroidism means decrease in the secretion of T₃ and T₄

2. Decrease in T₄ , i.e. thyroxine in the blood triggers negative feedback mechanism. 

3. The hormone receptors in hypothalamus detect this change and secrete TRE 

4. TRF stimulates the pituitary to secrete TSH 

5. Thus, Patient suffering from hypothyroidism shows increased level of TSH due to negative feedback control.