Q: Which equation correctly represents the negative feedback regulation of thyroid hormones?

$TSH \rightarrow T_3/T_4 \rightarrow \text{inhibition of TSH}$

Question 1

Krista’s brother has developed bulging eyes, a symptom commonly associated with Graves’ disease. Which of the following best explains the underlying mechanism for this symptom?

Accepted Answer

Autoantibodies stimulate the TSH receptor, leading to excess thyroid hormone and tissue inflammation behind the eyes.

Question 2

Which of the following is the most likely laboratory finding in a patient with Graves’ disease?

Accepted Answer

Low TSH, high T3 and T4

Question 3

Thyroid hormones are classified as which type of hormone, and what is their primary mechanism of action?

Accepted Answer

Amino acid-based hormones; they bind to nuclear receptors and regulate gene transcription.

Question 4

A patient with hypothyroidism would most likely present with which of the following symptoms?

Accepted Answer

Weight gain, cold intolerance, bradycardia

Question 5

Which equation correctly represents the negative feedback regulation of thyroid hormones?

Accepted Answer

$TSH ightarrow T_3/T_4 ightarrow 	ext{inhibition of TSH}$

Question 6

If Krista’s TSH levels are low and her T3/T4 levels are high, which of the following is the most likely diagnosis?

Accepted Answer

Primary hyperthyroidism (Graves’ disease)

Question 7

Which of the following best describes the difference between amino acid-based and steroid hormones?

Accepted Answer

Steroid hormones are synthesized from cholesterol and bind to intracellular receptors.

Question 8

A patient with untreated hypothyroidism is likely to have which of the following laboratory findings?

Accepted Answer

High TSH, low T3/T4

Question 9

Which of the following is a direct effect of thyroid hormones on metabolism?

Accepted Answer

Increase in protein synthesis and oxygen consumption

Question 10

Which of the following best explains why Krista’s doctor ordered blood tests to check her thyroid function after noting her symptoms?

Accepted Answer

Thyroid dysfunction can cause a wide range of systemic symptoms due to its role in regulating metabolism.

Question 11

Which hormone is secreted by the anterior pituitary and stimulates the thyroid gland?

Accepted Answer

Thyroid-stimulating hormone (TSH)

Question 12

A patient with Graves’ disease is likely to experience which of the following cardiovascular effects?

Accepted Answer

Tachycardia and increased cardiac output

Question 13

Which of the following best describes the autoimmune mechanism in Graves’ disease?

Accepted Answer

Antibodies stimulate the TSH receptor, causing excess thyroid hormone production.

Question 14

Which of the following is a common symptom of hyperthyroidism?

Accepted Answer

Heat intolerance

Question 15

Which of the following best explains why TSH levels are low in Graves’ disease?

Accepted Answer

High levels of thyroid hormones exert negative feedback on the pituitary gland.

Question 16

Which of the following is a correct statement about the solubility and mechanism of action of thyroid hormones?

Accepted Answer

Thyroid hormones are lipid-soluble and act via nuclear receptors.

Question 17

A patient with Hashimoto’s thyroiditis (autoimmune hypothyroidism) would most likely have which of the following findings?

Accepted Answer

High TSH, low T3/T4

Question 18

Which of the following best describes the role of thyroid hormones in growth and development?

Accepted Answer

They stimulate protein synthesis and are essential for normal growth and development.

Question 19

Which of the following is the correct sequence of hormone release in the hypothalamic-pituitary-thyroid axis?

Accepted Answer

$TRH \rightarrow TSH \rightarrow T_3/T_4$

Question 20

A patient presents with fatigue, weight gain, and dry skin. Laboratory tests reveal high TSH and low T4. Which of the following is the most likely diagnosis?

Accepted Answer

Primary hypothyroidism

Endocrine System Case Study: Thyroid Function and Hormones

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