Chapter 196
Activity 1
Which rat had the fastest baseline metabolic rate? Normal Rat
Why did the metabolic rates differ? The hypophysectomized rat lacked thyroid-stimulating hormone. The thyroidectomized rat lacked thyroxine hormone.
Activity 2
What was the effect of thyroxine on the normal rat’s metabolic rate? How does it compare to the normal rat’s baseline metabolic rate? Thyroxine caused the metabolic rate to increase; it was faster.
Why was this effect seen? Because it stimulates heart rate, heat, and other things related to metabolic rate
What was the effect of thyroxine on the thyroidectomized rat’s metabolic rate? How does it compare to the thyroidectomized rat’s baseline metabolic rate? Thyroxine caused the metabolic rate to increase; it was faster.
Why was this effect seen? This effect is seen because the throxine injected compensated for the thyroxine lost when thyroid was removed.
What was the effect of thyroxine on the hypophysectomized rat’s metabolic rate? How does it compare to the hypophysectomized rat’s baseline metabolic rate? Thyroxine caused the metabolic rate to increase; it was faster.
Activity 3
What was the effect of TSH on the normal rat’s metabolic rate? How does it compare to the normal rat’s baseline metabolic rate? TSH increased the metabolic rate; it was faster.
Why was this effect seen? The TSH increased production of thyroxine.
What was the effect of TSH on the thyroidectomized rat’s metabolic rate? How does it compare to the thyroidectomized rat’s baseline metabolic rate? It was the same as the baseline rate.
Why was this effect seen? Since there is no thyroid gland in the thyroidectomized rat, the injected TSH had nothing to act upon.
What was the effect of TSH on the hypophysectomized rat’s metabolic rate? How does it compare to the hypophysectomized rat’s baseline metabolic rate? TSH increased the metabolic rate; it was faster.
Why was this effect seen? The injected TSH compensated for the TSH lost
Which rat had the fastest baseline metabolic rate? Normal Rat
Why did the metabolic rates differ? The hypophysectomized rat lacked thyroid-stimulating hormone. The thyroidectomized rat lacked thyroxine hormone.
Activity 2
What was the effect of thyroxine on the normal rat’s metabolic rate? How does it compare to the normal rat’s baseline metabolic rate? Thyroxine caused the metabolic rate to increase; it was faster.
Why was this effect seen? Because it stimulates heart rate, heat, and other things related to metabolic rate
What was the effect of thyroxine on the thyroidectomized rat’s metabolic rate? How does it compare to the thyroidectomized rat’s baseline metabolic rate? Thyroxine caused the metabolic rate to increase; it was faster.
Why was this effect seen? This effect is seen because the throxine injected compensated for the thyroxine lost when thyroid was removed.
What was the effect of thyroxine on the hypophysectomized rat’s metabolic rate? How does it compare to the hypophysectomized rat’s baseline metabolic rate? Thyroxine caused the metabolic rate to increase; it was faster.
Activity 3
What was the effect of TSH on the normal rat’s metabolic rate? How does it compare to the normal rat’s baseline metabolic rate? TSH increased the metabolic rate; it was faster.
Why was this effect seen? The TSH increased production of thyroxine.
What was the effect of TSH on the thyroidectomized rat’s metabolic rate? How does it compare to the thyroidectomized rat’s baseline metabolic rate? It was the same as the baseline rate.
Why was this effect seen? Since there is no thyroid gland in the thyroidectomized rat, the injected TSH had nothing to act upon.
What was the effect of TSH on the hypophysectomized rat’s metabolic rate? How does it compare to the hypophysectomized rat’s baseline metabolic rate? TSH increased the metabolic rate; it was faster.
Why was this effect seen? The injected TSH compensated for the TSH lost