1 of 3 PhysioEx Lab Report Exercise 4: Endocrine System Physiology Activity 1: Metabolism and Thyroid Hormone Name: Date: 3 March 2021 Session ID: Pre-lab Quiz Results You have not completed the Pre-lab Quiz. Experiment Results You have not completed the Experiment. Post-lab Quiz Results You have not completed the Post-lab Quiz. Review Sheet Results 1 Part 1: Determining the Basal Metabolic Rates Which rat had the fastest basal metabolic rate (BMR)? Your answer: The normal rat. 2 Why did the metabolic rates diﬀer between the normal rat and the surgically altered rats? How well did the results compare with your prediction? Your answer: The organs that play an important role for maintaining the BMR were removed in the other rats. 3 If an animal has been thyroidectomized, what hormone(s) would be missing in its blood? Your answer: Thyroxine. 3/3/2021, 7:13 PM 2 of 3 4 If an animal has been hypophysectomized, what eﬀect would you expect to observe in the hormone levels in its body? Your answer: The animal would lose TSH so nothing could stimulate the the thyroid to secret thyroxine. 5 Part 2: Determining the Eﬀect of Thyroxine on Metabolic Rate What was the eﬀect of thyroxine injections on the normal rat's BMR? Your answer: The rat became hyperthyroidic. 6 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? Your answer: The BMR was increased to 1935. Which is lower than normal but it is higher than normal without drugs because the BMR was over 1800 thyroxine so the dose was too big. 7 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? Your answer: The BMR was raised to 1895, but it is not as high as the thyroidectimized or normal rats with thyroxine because it is over 1800 so the dose was too big. 8 Part 3: Determining the Eﬀect of TSH on Metabolic Rate What was the eﬀect of thyroid-stimulating hormone (TSH) injections on the normal rat's BMR? Your answer: The normal rat was hyperthyroidic. 9 What was the eﬀect of TSH injections on the thyroidectomized rat's BMR? How does the BMR in this case compare with the normal rat's BMR? Why was this eﬀect observed? 3/3/2021, 7:13 PM 3 of 3 Your answer: It didn't raise the BMR, it remained in hypothyroid under 1600. 10 What was the eﬀect of TSH 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 TSH in the syringe too large, too small, or just right? Your answer: The dose was too large because it became 1918 below the normal but it went to hyperthyroid. 11 Part 4: Determining the Eﬀect of Propylthiouracil on Metabolic Rate What was the eﬀect of propylthiouracil (PTU) injections on the normal rat's BMR? Why did this rat develop a palpable goiter? Your answer: The administration of the PTU injection into the normal rat resulted in the decrease on the BMR. The palpable goiter was developed because of the accumulations of antecedents to thyroxine. 12 What was the eﬀect of PTU injections on the thyroidectomized rat's BMR? How does the BMR in this case compare with the normal rat's BMR? Why was this eﬀect observed? Your answer: The eﬀect of the PTU injections on the throidectomized rat was not visible because there is no thyroid gland present in this rat to be stimulated. 13 What was the eﬀect of PTU injections on the hypophysectomized rat's BMR? How does the BMR in this case compare with the normal rat's BMR? Why was this eﬀect observed? Your answer: The eﬀect of PTU injections into the hypophysectomized rat is not visible as there is no pituitary gland present in this rat to be stimulated. 3/3/2021, 7:13 PM