Question

Unit A: Assignment 2A han Module 2 The Endocrine System 0 33 Apostres an enlargement of the thyroid gland, resulting in a large swering of the neck. It can lead to swallowing or breathing problems. It is most commonly caused by inadequate amounts of dietary lodine. Iodine is essential in thyroxine synthesis Enlargement of the thyroid gland occurs A due to increased levels of TSH B. due to decreased levels of thyroxine C. due to increased levels of thyroxine D. due to decreased levels of TSH Use the following information to answer question 34. Select the numbers of the descriptors below that correctly describe the hormone thyroxine. 1. Produced in the parathyroid gland 2. Produced in the thyroid gland 3. Increases the rate of fat, protein, and carbohydrate metabolism 4. Increases the rate of calcium ion absorption 5. Controlled by positive feedback 6. Controlled by negative feedback 7. Insufficiency results in fatigue and weight gain 8. Insufficiency results in excess energy and weight loss 34. Record your answers in ascending (lowest to highest) order. ADLC | Biology 30

Answer 1

33. Enlargement of thyroid gland occurs in case of goitre. Low iodine level in the diet decreases the production of thyroxine in the thyroid follicles which in turn stimulates production of thyroid stimulating hormone (TSH)from the anterior pituitary. Increased TSH secretion leads to increase cellular growth and proliferation which is the cause of the thyroid enlargement.

correct answer is A.

34. 2,3,6,7

2. Thyroxine is produced by the thyroid gland.

3. Thyroxine promotes the metabolism of fats, carbohydrates and proteins.

6. Thyroxine secretion is controlled by the negative feedback regulation.

7. Thyroxine promotes metabolism and insufficiency causes fatigue and weight gain.