English英语词条或短语:extreme nervousness and an increase in heart action
The thyroid gland may be underactive or overactive, resulting in problems. An underactive thyroid causes hypothyroidism, while an overactive one causes hyperthyroidism. The former problem, called myxedema in adults and cretinism in children, causes the growth process to slow down. A cretin’s body and mind do not grow to their full potential. Hyperthyroidism, on the other hand, results in extreme nervousness, an increase in heart action, and other problems.