30 Questions
What is the effect of injecting Thyroxine on a person with no thyroid gland?
Increased metabolic rate
What is the effect of injecting PTU on a person with normal thyroid function?
Lowers metabolic rate
What is the characteristic of a person with Graves' disease?
Too much T3
What is the effect of injecting TSH on a person with normal thyroid function?
Increased BMR
What is the characteristic of a person with no adenohypophysis?
Low TSH
What is the effect of injecting Thyroxine on a person with no adenohypophysis?
Decreased TRH
What is the primary effect of injecting TSH on a person with normal thyroid function?
Increased T3/T4 production
What is the primary mechanism of Propothyuricil (PTU) in reducing thyroid hormone production?
Blocking iodination of tyrosine in the thyroid gland
What is the characteristic of a person with no thyroid gland in terms of TSH levels?
Increased TSH levels
What is the effect of injecting Thyroxine on a person with normal thyroid function?
Increased metabolic rate
What is the primary function of deiodinase enzyme in the tissue?
Converting T4 to T3
What is the characteristic of Graves' disease in terms of thyroid gland size?
Enlarged thyroid gland
What happens to the BMR when TSH is injected into a person with no thyroid gland?
It remains unaffected
What is the effect of Propothyuricil on the conversion of T4 to T3 in the tissue?
It blocks the conversion
What is the characteristic of a person with normal thyroid function when Thyroxine is injected?
Increased BMR
What is the effect of injecting PTU on a person with no adenohypophysis?
It has no effect on the production of T3 and T4
What is the primary mechanism of Graves' disease?
Autoantibody that overstimulates TSH signal on thyroid
What is the effect of injecting TSH on a person with no thyroid gland?
It has no effect on the production of T3 and T4
Injecting TSH into a person with no thyroid gland will decrease their TSH levels.
False
In a person with normal thyroid function, injecting PTU will increase their BMR.
False
A person with Graves' disease will have a lower TSH level due to negative feedback.
False
In a person with no adenohypophysis, injecting Thyroxine will stimulate the hypothalamus to produce more TRH.
False
Propothyuricil (PTU) blocks the conversion of T3 to T4 in the thyroid gland.
False
In a person with no thyroid gland, injecting TSH will stimulate the production of T3 and T4.
False
In a person with normal thyroid function, injecting Thyroxine will eventually lead to suppression of the thyroid hormone production.
True
A person with no thyroid gland will have a low TSH level due to negative feedback.
False
In a person with no adenohypophysis, injecting TSH will stimulate the production of T3 and T4.
False
Propothyuricil (PTU) blocks the conversion of T4 to T3 in the thyroid gland.
False
In a person with Graves' disease, the hypothalamus will produce more TRH due to low T3 and T4 levels.
False
In a person with normal thyroid function, injecting PTU will decrease the metabolic rate.
True
Study Notes
Normal Thyroid Function
- BMR and hormone production are unaffected
- Injecting Thyroxine (T4) leads to:
- 2x thyroid hormone production
- Eventually, suppression/dependency of the system
- Injecting TSH leads to:
- Increased BMR
- Stimulation of thyroid function
- Injecting PTU leads to:
- Decreased metabolic rate
- Decreased T3/T4 conversion in thyroid
- Decreased T4 to T3 conversion in tissue
No Thyroid (Hypothyroidism)
- Increased TSH (no binding site)
- Decreased/absent T3/T4 (no stimulation)
- Signals to hypothalamus that levels are low
- Injecting Thyroxine (T4) leads to:
- Increased metabolic rate
- Increased T3/T4
- Injecting TSH has no effect (no thyroid to bind to)
- Injecting PTU has no effect (no T3 to convert, already decreased T4)
No Adenohypophysis (Hypopituitarism)
- Low/no TSH
- Increased TRH (no binding site)
- T3/T4 levels are low, signaling hypothalamus to produce TRH
- Injecting Thyroxine (T4) leads to:
- Increased T3/T4
- Decreased TRH
- Injecting TSH leads to:
- Increased BMR
- Stimulation of thyroid function (if present)
- Injecting PTU has no effect (no TSH to produce T3/T4)
Propylthiouracil (PTU) and Thyroid Hormone Production
- PTU blocks tyrosine iodination, preventing T4 production
- PTU also blocks deiodinase enzyme, preventing T4 to T3 conversion in tissue
- Storage forms of T4 are low due to PTU
Graves' Disease
- Autoantibody overstimulates TSH signal on thyroid
- Leads to excessive T3 production
- Thyroid gland becomes too large due to TSH stimulation
- T3 vs T4 ratio: 1:9 (T4 to T3), with T3 being the most effective
Normal Thyroid Function
- BMR and hormone production are unaffected
- Injecting Thyroxine (T4) leads to:
- 2x thyroid hormone production
- Eventually, suppression/dependency of the system
- Injecting TSH leads to:
- Increased BMR
- Stimulation of thyroid function
- Injecting PTU leads to:
- Decreased metabolic rate
- Decreased T3/T4 conversion in thyroid
- Decreased T4 to T3 conversion in tissue
No Thyroid (Hypothyroidism)
- Increased TSH (no binding site)
- Decreased/absent T3/T4 (no stimulation)
- Signals to hypothalamus that levels are low
- Injecting Thyroxine (T4) leads to:
- Increased metabolic rate
- Increased T3/T4
- Injecting TSH has no effect (no thyroid to bind to)
- Injecting PTU has no effect (no T3 to convert, already decreased T4)
No Adenohypophysis (Hypopituitarism)
- Low/no TSH
- Increased TRH (no binding site)
- T3/T4 levels are low, signaling hypothalamus to produce TRH
- Injecting Thyroxine (T4) leads to:
- Increased T3/T4
- Decreased TRH
- Injecting TSH leads to:
- Increased BMR
- Stimulation of thyroid function (if present)
- Injecting PTU has no effect (no TSH to produce T3/T4)
Propylthiouracil (PTU) and Thyroid Hormone Production
- PTU blocks tyrosine iodination, preventing T4 production
- PTU also blocks deiodinase enzyme, preventing T4 to T3 conversion in tissue
- Storage forms of T4 are low due to PTU
Graves' Disease
- Autoantibody overstimulates TSH signal on thyroid
- Leads to excessive T3 production
- Thyroid gland becomes too large due to TSH stimulation
- T3 vs T4 ratio: 1:9 (T4 to T3), with T3 being the most effective
Normal Thyroid Function
- BMR and hormone production are unaffected
- Injecting Thyroxine (T4) leads to:
- 2x thyroid hormone production
- Eventually, suppression/dependency of the system
- Injecting TSH leads to:
- Increased BMR
- Stimulation of thyroid function
- Injecting PTU leads to:
- Decreased metabolic rate
- Decreased T3/T4 conversion in thyroid
- Decreased T4 to T3 conversion in tissue
No Thyroid (Hypothyroidism)
- Increased TSH (no binding site)
- Decreased/absent T3/T4 (no stimulation)
- Signals to hypothalamus that levels are low
- Injecting Thyroxine (T4) leads to:
- Increased metabolic rate
- Increased T3/T4
- Injecting TSH has no effect (no thyroid to bind to)
- Injecting PTU has no effect (no T3 to convert, already decreased T4)
No Adenohypophysis (Hypopituitarism)
- Low/no TSH
- Increased TRH (no binding site)
- T3/T4 levels are low, signaling hypothalamus to produce TRH
- Injecting Thyroxine (T4) leads to:
- Increased T3/T4
- Decreased TRH
- Injecting TSH leads to:
- Increased BMR
- Stimulation of thyroid function (if present)
- Injecting PTU has no effect (no TSH to produce T3/T4)
Propylthiouracil (PTU) and Thyroid Hormone Production
- PTU blocks tyrosine iodination, preventing T4 production
- PTU also blocks deiodinase enzyme, preventing T4 to T3 conversion in tissue
- Storage forms of T4 are low due to PTU
Graves' Disease
- Autoantibody overstimulates TSH signal on thyroid
- Leads to excessive T3 production
- Thyroid gland becomes too large due to TSH stimulation
- T3 vs T4 ratio: 1:9 (T4 to T3), with T3 being the most effective
Normal Thyroid Function
- BMR and hormone production are unaffected
- Injecting Thyroxine (T4) leads to:
- 2x thyroid hormone production
- Eventually, suppression/dependency of the system
- Injecting TSH leads to:
- Increased BMR
- Stimulation of thyroid function
- Injecting PTU leads to:
- Decreased metabolic rate
- Decreased T3/T4 conversion in thyroid
- Decreased T4 to T3 conversion in tissue
No Thyroid (Hypothyroidism)
- Increased TSH (no binding site)
- Decreased/absent T3/T4 (no stimulation)
- Signals to hypothalamus that levels are low
- Injecting Thyroxine (T4) leads to:
- Increased metabolic rate
- Increased T3/T4
- Injecting TSH has no effect (no thyroid to bind to)
- Injecting PTU has no effect (no T3 to convert, already decreased T4)
No Adenohypophysis (Hypopituitarism)
- Low/no TSH
- Increased TRH (no binding site)
- T3/T4 levels are low, signaling hypothalamus to produce TRH
- Injecting Thyroxine (T4) leads to:
- Increased T3/T4
- Decreased TRH
- Injecting TSH leads to:
- Increased BMR
- Stimulation of thyroid function (if present)
- Injecting PTU has no effect (no TSH to produce T3/T4)
Propylthiouracil (PTU) and Thyroid Hormone Production
- PTU blocks tyrosine iodination, preventing T4 production
- PTU also blocks deiodinase enzyme, preventing T4 to T3 conversion in tissue
- Storage forms of T4 are low due to PTU
Graves' Disease
- Autoantibody overstimulates TSH signal on thyroid
- Leads to excessive T3 production
- Thyroid gland becomes too large due to TSH stimulation
- T3 vs T4 ratio: 1:9 (T4 to T3), with T3 being the most effective
Normal Thyroid Function
- BMR and hormone production are unaffected
- Injecting Thyroxine (T4) leads to:
- 2x thyroid hormone production
- Eventually, suppression/dependency of the system
- Injecting TSH leads to:
- Increased BMR
- Stimulation of thyroid function
- Injecting PTU leads to:
- Decreased metabolic rate
- Decreased T3/T4 conversion in thyroid
- Decreased T4 to T3 conversion in tissue
No Thyroid (Hypothyroidism)
- Increased TSH (no binding site)
- Decreased/absent T3/T4 (no stimulation)
- Signals to hypothalamus that levels are low
- Injecting Thyroxine (T4) leads to:
- Increased metabolic rate
- Increased T3/T4
- Injecting TSH has no effect (no thyroid to bind to)
- Injecting PTU has no effect (no T3 to convert, already decreased T4)
No Adenohypophysis (Hypopituitarism)
- Low/no TSH
- Increased TRH (no binding site)
- T3/T4 levels are low, signaling hypothalamus to produce TRH
- Injecting Thyroxine (T4) leads to:
- Increased T3/T4
- Decreased TRH
- Injecting TSH leads to:
- Increased BMR
- Stimulation of thyroid function (if present)
- Injecting PTU has no effect (no TSH to produce T3/T4)
Propylthiouracil (PTU) and Thyroid Hormone Production
- PTU blocks tyrosine iodination, preventing T4 production
- PTU also blocks deiodinase enzyme, preventing T4 to T3 conversion in tissue
- Storage forms of T4 are low due to PTU
Graves' Disease
- Autoantibody overstimulates TSH signal on thyroid
- Leads to excessive T3 production
- Thyroid gland becomes too large due to TSH stimulation
- T3 vs T4 ratio: 1:9 (T4 to T3), with T3 being the most effective
This quiz covers the effects of injecting thyroxine, TSH, and PTU on thyroid hormone production, metabolic rate, and thyroid function. Understand how the thyroid system responds to different hormones and medications.
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