NEGATIVE FEEDBACK MECHANISM ON TSH
Describe the negative feedback mechanism involving TSH and thyroxin
and describe the consequences of abnormal level of TSH.
When the thyroxin level is low
• The pituitary gland become stimulated to secrete more TSH
• TSH stimulates the thyroid gland
• To secrete more thyroxin
• Thus increasing the level of thyroxin in the blood to normal levels.
When the thyroxin level is high
• The pituitary gland is not stimulated to release TSH
• There is less stimulation of thyroid gland to secrete thyroxin
• Thus decreasing the levels of thyroxin back to normal.
Consequences of abnormal level of TSH
This causes hyperthyroidism:
High level of TSH which results in (weight loss, inability, hyperactivity,
increase in heart rate, tiredness)
Low level of TSH which results in (weight gain, decrease in heart rate,
slow growth of hair and fingernails)
Describe the negative feedback mechanism involving TSH and thyroxin
and describe the consequences of abnormal level of TSH.
When the thyroxin level is low
• The pituitary gland become stimulated to secrete more TSH
• TSH stimulates the thyroid gland
• To secrete more thyroxin
• Thus increasing the level of thyroxin in the blood to normal levels.
When the thyroxin level is high
• The pituitary gland is not stimulated to release TSH
• There is less stimulation of thyroid gland to secrete thyroxin
• Thus decreasing the levels of thyroxin back to normal.
Consequences of abnormal level of TSH
This causes hyperthyroidism:
High level of TSH which results in (weight loss, inability, hyperactivity,
increase in heart rate, tiredness)
Low level of TSH which results in (weight gain, decrease in heart rate,
slow growth of hair and fingernails)
