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Exercise 4 Physiolab 9.0

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Exercise 4 Physiolab 9.0

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ACTIVITY 1: Metabolism and Thyroid Hormones – Part 1Answers 1.The baseline metabolic rate (BMR) of the normal rat was approximately ________ ml O2/kg/hr.426 2.True or False: The BMR of all three rats was approximately the same before treatment with thyroxine, TSH, or propylthiouracil. true 3.Which rat had the fastest basal metabolic rate (BMR)? normal 4. Why did the BMR’s differ between the normal rat and the surgically altered rats?Because the metabolism of the normal rat was normal. The Tx and Hypox rats’ metabolism was altered from the removal of the pituitary gland (Hypox rat) and the thyroid gland (Tx rat) these glands are essential for the regulation of metabolism. 5.If an animal had been thyroidectomized, what hormone(s) would be missing in its blood? Thyroxine 6.If an animal had been hypophysectomized, what effect(s) would you expect to see in the hormone levels in its blood and in its BMR? ACTIVITY 1: Metabolism and Thyroid Hormones – Part 2

7.True or False: The thyroxine injections caused a goiter in the normal rat. 8.After the thyroxine injection, the BMR (in ml O2/kg/hr) of the thyroidectomized rat was approximately a.1700
b.1800
c.1900
d.2000
9.True or False: The term euthyroid means that the amount of thyroid hormone present in that specific animal is within the normal range. 10.What was the effect of thyroxine injections on the normal rat’s BMR? 11.What was the effect of thyroxine injections on the thyroidectomized rat’s BMR? How does the BMR in this case compare with the normal rat’s BMR? Was the dose of thyroxine in the syringe too large, too small, or just right? 12.What was the effect of thyroxine injections on the hypophysectomized rat’s BMR? How does the BMR in this case compare with the normal rat’s BMR? Was the dose of thyroxine in the syringe too large, too small, or just right? ACTIVITY 1: Metabolism and Thyroid Hormones – Part 3

13.The hormone TSH is synthesized and secreted from...