[PhysioEX Chapter 4 exercise 1] PEX-04-01

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Exercise 4: Endocrine System Physiology: Activity 1: Metabolism and Thyroid Hormone Lab Report

Pre-lab Quiz Results
You scored 100% by answering 6 out of 6 questions correctly.

1. Which of the following statements about metabolism is false?
   You correctly answered: d. All of the energy from metabolism is ultimately stored in the chemical bonds of ATP.
2. Thyroxine is
   You correctly answered: c. the most important hormone for maintaining the metabolic rate and body temperature.
3. Thyroid-stimulating hormone (TSH) is
   You correctly answered: b. produced in the pituitary gland.
4. An injection of TSH to an otherwise normal animal will cause which of the following?
   You correctly answered: d. goiter development
5. Thyrotropin-releasing hormone (TRH) is
   You correctly answered: a. secreted by the hypothalamus.
6. Which of the following statements is true?
   You correctly answered: b. The hypothalamus primarily secretes tropic hormones that stimulate the secretion of other
   hormones.
   06/02/15 page 1

Experiment Results
Predict Question:
Predict Question 1: Make a prediction about the basal metabolic rate (BMR) of the remaining rats compared with the BMR
of the normal rat you just measured.
Your answer : c. The BMR of both remaining rats will be lower than the normal rat's BMR.

Predict Question 2: What do you think will happen after you inject thyroxine into the three rats?
Your answer : a. The normal rat will become hyperthyroidic and develop a goiter.

Predict Question 3: What do you think will happen after you inject TSH into the three rats?
Your answer : a. The normal rat will become hyperthyroidic and develop a goiter.

Predict Question 4: Propylthiouracil (PTU) is a drug that inhibits the production of thyroxine by blocking the attachment of
iodine to tyrosine residues in the follicle cells of the thyroid gland (iodinated tyrosines are linked together to form thyroxine).
What do you think will happen after you inject PTU into the three rats?
Your answer : b. The thyroidectomized rat will become hypothyroidic and develop a goiter.

Stop & Think Questions:
1h. Calculate the oxygen consumption per hour for this rat using the following equation.

ml O2 consumed/1 minute x 60 minutes/hour = ml O2/hour

Enter the oxygen consumption per hour in the field below and then click Submit to display your results in the grid.
You answered: 432 ml O2/hr

1i. Now that you have calculated the oxygen consumption per hour for this rat, you can calculate the metabolic rate per
kilogram of body weight with the following equation (note that you need to convert the weight data from grams to kilograms
to use this equation).

Metabolic rate = (ml O2/hr)/(weight in kg) = ml O2/kg/hr

Enter the metabolic rate in the field below and then click Submit to display your results in the grid. .
You answered: 1734-939759036145 ml O2/kg/hr

2h. Calculate the oxygen consumption per hour for this rat using the following equation.

ml O2 consumed/1 minute x 60 minutes/hour = ml O2/hour

Enter the oxygen consumption per hour in the field below and then click Submit to display your results in the grid.
You answered: 378 ml O2/hr

2i. Now that you have calculated the oxygen consumption per hour for this rat, you can calculate the metabolic rate per
kilogram of body weight with the following equation (note that you need to convert the weight data from grams to kilograms
to use this equation).

Metabolic rate = (ml O2/hr)/(weight in kg) = ml O2/kg/hr

Enter the metabolic rate in the field below and then click Submit to display your results in the grid.

06/02/15 page 2

You answered: 1542.857142857143 ml O2/kg/hr
3h. Calculate the oxygen consumption per hour for this rat using the following equation.
ml O2 consumed/1 minute x 60 minutes/hour = ml O2/hour
Enter the oxygen consumption per hour in the field below and then click Submit to display your results in the grid.
You answered: 372 ml O2/hr
3i. Now that you have calculated the oxygen consumption per hour for this rat, you can calculate the metabolic rate per
kilogram of body weight with the following equation (note that you need to convert the weight data from grams to kilograms
to use this equation).
Metabolic rate = (ml O2/hr)/(weight in kg) = ml O2/kg/hr
Enter the metabolic rate in the field below and then click Submit to display your results in the grid.
You answered: 1524.590163934426 ml O2/kg/hr
Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid
levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthryoid (high thyroid
levels; BMR above 1800).
The normal rat is
You correctly answered: b. euthyroid
Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid
levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthryoid (high thyroid
levels; BMR above 1800).
The thyroidectomized (Tx) rat is
You correctly answered: a. hypothyroid
Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid
levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthryoid (high thyroid
levels; BMR above 1800).
The hypophysectomized (Hypox) rat is
You correctly answered: a. hypothyroid
Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid
levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthryoid (high thyroid
levels; BMR above 1800) after the thyroxine injection.
The normal rat is
You correctly answered: c. hyperthyroid
Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid
levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthryoid (high thyroid
levels; BMR above 1800) after the thyroxine injection.
06/02/15 page 3

The thyroidectomized (Tx) rat is
You correctly answered: c. hyperthyroid
Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid
levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthryoid (high thyroid
levels; BMR above 1800) after the thyroxine injection.
The hypophysectomized (Hypox) rat is
You correctly answered: c. hyperthyroid
Which of the rats developed a goiter after injection with thyroxine (select all that apply)?
You correctly answered: d. None of the rats developed a goiter with this injection.
Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid
levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthryoid (high thyroid
levels; BMR above 1800) after the TSH injection.
The normal rat is
You correctly answered: c. hyperthyroid
Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid
levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthryoid (high thyroid
levels; BMR above 1800) after the TSH injection.
The thyroidectomized (Tx) rat is
You correctly answered: a. hypothyroid
Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid
levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthryoid (high thyroid
levels; BMR above 1800) after the TSH injection.
The hypophysectomized (Hypox) rat is
You correctly answered: c. hyperthyroid
Which of the rats developed a goiter after injection with TSH (select all that apply)?
You correctly answered: a. the normal rat c. the hypophysectomized rat
Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid
levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthryoid (high thyroid
levels; BMR above 1800) after the PTU injection.
The normal rat is
You correctly answered: a. hypothyroid
Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid
levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthryoid (high thyroid
levels; BMR above 1800) after the PTU injection.
The thyroidectomized (Tx) rat is
You correctly answered: a. hypothyroid
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Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid
levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthryoid (high thyroid
levels; BMR above 1800) after the PTU injection.
The hypophysectomized (Hypox) rat is
You correctly answered: a. hypothyroid
Which of the rats developed a goiter after injection with PTU (select all that apply)?
You correctly answered: a. the normal rat
Experiment Data:
Rat Weight (g) ml O2/min ml O2/hr BMR
(ml O2/kg/hr)
Palpation Injected
Normal 249 7.2 432 1734-939759
036145
No mass none
Tx 245 6.3 378 1542.857142
857143
No mass none
Hypox 244 6.2 372 1524.590163
934426
No mass none
Normal 249 8.4 504 2024 No mass Thyroxine
Tx 245 7.9 474 1935 No mass Thyroxine
Hypox 244 7.7 462 1893 No mass Thyroxine
Normal 249 8 480 1928 Mass TSH
Tx 245 6.3 378 1543 No mass TSH
Hypox 244 7.8 468 1918 Mass TSH
Normal 249 6.4 384 1542 Mass PTU
Tx 245 6.2 372 1518 No mass PTU
Hypox 244 6.3 378 1549 No mass PTU
06/02/15 page 5

Post-lab Quiz Results
You scored 100% by answering 7 out of 7 questions correctly.

1. How would you treat a thyroidectomized animal so that it functions like a "normal" animal?
   You correctly answered: c. Provide the animal T4 supplements.
2. As a result of the missing hormone(s) in the hypophysectimized rat, what would be some expected symptoms?
   You correctly answered: d. decreased basal metabolic rate
3. An injection of thyroxine to an otherwise normal rat will cause which of the following?
   You correctly answered: b. hyperthyroidism
4. Why didn't any of the rats develop a goiter after thyroxine injection?
   You correctly answered: a. In all cases, TSH levels were not elevated by the thyroxine injection.
5. Why did the normal rat develop a palpable goiter with the TSH injection?
   You correctly answered: c. The TSH receptors on the thyroid gland were excessively stimulated.
6. An injection of propylthiouracil to an otherwise normal animal will cause which of the following?
   You correctly answered: b. goiter development
7. Why did the normal rat develop a palpable goiter with the propylthiouracil injection?
   You correctly answered: d. The injection decreased the negative feedback mechanism on TSH.
   06/02/15 page 6

Review Sheet Results

1. Part 1: Determining the Basal Metabolic Rates
   Which rat had the fastest basal metabolic rate (BMR)?
   Your answer:
   normal

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:
   Because the organs that play an important role for maintaining the BMR were removed in the other rats, such as thyroid or
   pituitary gland, as I predicted

3. If an animal has been thyroidectomized, what hormone(s) would be missing in its blood?
   Your answer:
   Thyroxine

4. If an animal has been hypophysectomized, what effect would you expect to see in the hormone levels in its body?
   Your answer:
   The animal would lose TSH so nothing can stimulate the thyroid to secrete 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:
   It becomes 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:
   BMR was increased to 1935
   But still lower than normal, but higher than normal without drugs
   cause BMR was over than 1800 thyroxine, dose was too large

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:
   It raised the BMR to 1895, but not as high as the thyroidectomized or normal rats with thyroxine
   cause it is over than 1800, dose was too large

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 ray became 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?
   06/02/15 page 7

Your answer:
it did not raise the BMR almost
it was still remaind in hypothyroid under 1600

1. 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:
   it became 1918 below the normal, but it went to hyperthyroid
   so dose was too large