Thyroid Function and Disorders

The video discusses the actions of thyroid hormones, focusing on T4 and T3. T4 is the inactive form, converted to T3 in tissues. T3 is a catabolic hormone, increasing blood glucose, lipolysis, and proteolysis. It also raises basal metabolic rate and body temperature. Thyroid hormones are crucial for growth, brain development, and myocardial sensitivity to catecholamines. Differences between hypothyroidism and hyperthyroidism are explored, highlighting TSH levels as a diagnostic tool. Congenital hypothyroidism leads to cretinism, while refit of syndrome involves T4 resistance.

Which enzyme is responsible for converting T4 to T3 in peripheral tissues?

• 5' deiodinase

• Hydroxylase

• Thyroid peroxidase

• Aromatase

What is the primary effect of T3 on blood glucose levels?

• Decreases blood glucose levels

• No effect on blood glucose levels

• Increases blood glucose levels

• Stabilizes blood glucose levels

How does T3 affect the basal metabolic rate?

• Decreases the basal metabolic rate

• Increases the basal metabolic rate

• Has no effect on the basal metabolic rate

• Stabilizes the basal metabolic rate

What role does T3 play in body temperature regulation?

• Decreases body temperature

• Increases body temperature

• Has no effect on body temperature

• Stabilizes body temperature

Why are thyroid hormones crucial during childhood?

• They are not important during childhood

• They are crucial for bone growth and brain development

• They only affect muscle growth

• They only influence height

How does T3 affect myocardial cells?

• Decreases sensitivity to catecholamines

• Increases sensitivity to catecholamines

• Decreases heart rate

• Has no effect on myocardial cells

What is a key indicator for diagnosing hypothyroidism and hyperthyroidism?

• T4 levels

• T3 levels

• Calcium levels

• TSH levels

In hypothyroidism, what happens to TSH levels?

• TSH levels increase

• TSH levels remain unchanged

• TSH levels decrease

• TSH levels fluctuate

What condition is characterized by a lack of T3 and T4 production at birth?

• Graves' disease

• Cretinism

• Hyperthyroidism

• Hashimoto's thyroiditis

What is Refetoff syndrome characterized by?

• Normal T4 and TSH levels

• Elevated T4 and TSH levels

• Decreased T4 and TSH levels

• Only elevated TSH levels