ENDOCRINOLOGY EXAM 1 QUESTIONS AND ANSWERS
What type of receptor mediates thyroid hormone action? - CORRECT ANSWER✅✅Intracellular nuclear
receptors.
Where are thyroid hormone receptors located? - CORRECT ANSWER✅✅In the nucleus of target cells.
Which thyroid hormone primarily binds nuclear receptors? - CORRECT ANSWER✅✅T3.
How does T3 alter gene expression? - CORRECT ANSWER✅✅Binds thyroid hormone receptor and
increases transcription of target genes.
What happens to cellular metabolism when thyroid hormone increases gene transcription? - CORRECT
ANSWER✅✅Increased metabolic rate.
What effect do thyroid hormones have on mitochondrial activity? - CORRECT ANSWER✅✅Increase
mitochondrial number and activity.
How do thyroid hormones affect basal metabolic rate? - CORRECT ANSWER✅✅Increase basal
metabolic rate.
How do thyroid hormones affect oxygen consumption? - CORRECT ANSWER✅✅Increase oxygen
consumption in most tissues.
What metabolic effect do thyroid hormones have on carbohydrates? - CORRECT ANSWER✅✅Increase
glucose absorption and metabolism.
What metabolic effect do thyroid hormones have on lipids? - CORRECT ANSWER✅✅Increase lipolysis
and cholesterol metabolism.
How do thyroid hormones affect protein metabolism? - CORRECT ANSWER✅✅Increase protein
synthesis but excess causes protein breakdown.
,What cardiovascular effect results from thyroid hormone? - CORRECT ANSWER✅✅Increased heart rate
and cardiac output.
How do thyroid hormones increase heart rate? - CORRECT ANSWER✅✅Upregulate beta-adrenergic
receptors.
What effect do thyroid hormones have on peripheral vascular resistance? - CORRECT
ANSWER✅✅Decrease peripheral resistance due to vasodilation.
How do thyroid hormones affect the nervous system? - CORRECT ANSWER✅✅Increase alertness,
reflexes, and neural development.
What is the role of TRH in the HPT axis? - CORRECT ANSWER✅✅Stimulates TSH release from the
anterior pituitary.
Where is TRH produced? - CORRECT ANSWER✅✅Hypothalamus.
What is the role of TSH in thyroid hormone regulation? - CORRECT ANSWER✅✅Stimulates thyroid
hormone synthesis and release.
Where is TSH produced? - CORRECT ANSWER✅✅Anterior pituitary thyrotrophs.
How do T3 and T4 regulate the HPT axis? - CORRECT ANSWER✅✅Negative feedback on hypothalamus
and pituitary.
What is the overall function of the hypothalamic-pituitary-thyroid axis? - CORRECT
ANSWER✅✅Maintain stable thyroid hormone levels.
What is thyroid storm? - CORRECT ANSWER✅✅A life-threatening exacerbation of hyperthyroidism with
severe metabolic and cardiovascular symptoms.
, What are common triggers of thyroid storm? - CORRECT ANSWER✅✅Infection, surgery, trauma, or
untreated hyperthyroidism.
What symptoms are seen in thyroid storm? - CORRECT ANSWER✅✅High fever, tachycardia, agitation,
vomiting, and delirium.
What causes exophthalmos in Graves disease? - CORRECT ANSWER✅✅Autoimmune inflammation and
glycosaminoglycan deposition behind the eyes.
What condition is associated with severe hypothyroidism and skin thickening? - CORRECT
ANSWER✅✅Myxedema.
What causes myxedema in hypothyroidism? - CORRECT ANSWER✅✅Accumulation of
glycosaminoglycans in skin and tissues.
What life-threatening complication occurs in severe hypothyroidism? - CORRECT
ANSWER✅✅Myxedema coma.
What are the main drugs used to treat hyperthyroidism? - CORRECT ANSWER✅✅Thionamides,
radioactive iodine, beta-blockers, and iodides.
What are examples of thionamide drugs? - CORRECT ANSWER✅✅Methimazole and propylthiouracil
(PTU).
What enzyme is inhibited by thionamides? - CORRECT ANSWER✅✅Thyroid peroxidase.
What effect does thyroid peroxidase inhibition have? - CORRECT ANSWER✅✅Blocks iodination and
coupling reactions in thyroid hormone synthesis.
Which thionamide also inhibits peripheral T4 to T3 conversion? - CORRECT ANSWER✅✅Propylthiouracil
(PTU).
What type of receptor mediates thyroid hormone action? - CORRECT ANSWER✅✅Intracellular nuclear
receptors.
Where are thyroid hormone receptors located? - CORRECT ANSWER✅✅In the nucleus of target cells.
Which thyroid hormone primarily binds nuclear receptors? - CORRECT ANSWER✅✅T3.
How does T3 alter gene expression? - CORRECT ANSWER✅✅Binds thyroid hormone receptor and
increases transcription of target genes.
What happens to cellular metabolism when thyroid hormone increases gene transcription? - CORRECT
ANSWER✅✅Increased metabolic rate.
What effect do thyroid hormones have on mitochondrial activity? - CORRECT ANSWER✅✅Increase
mitochondrial number and activity.
How do thyroid hormones affect basal metabolic rate? - CORRECT ANSWER✅✅Increase basal
metabolic rate.
How do thyroid hormones affect oxygen consumption? - CORRECT ANSWER✅✅Increase oxygen
consumption in most tissues.
What metabolic effect do thyroid hormones have on carbohydrates? - CORRECT ANSWER✅✅Increase
glucose absorption and metabolism.
What metabolic effect do thyroid hormones have on lipids? - CORRECT ANSWER✅✅Increase lipolysis
and cholesterol metabolism.
How do thyroid hormones affect protein metabolism? - CORRECT ANSWER✅✅Increase protein
synthesis but excess causes protein breakdown.
,What cardiovascular effect results from thyroid hormone? - CORRECT ANSWER✅✅Increased heart rate
and cardiac output.
How do thyroid hormones increase heart rate? - CORRECT ANSWER✅✅Upregulate beta-adrenergic
receptors.
What effect do thyroid hormones have on peripheral vascular resistance? - CORRECT
ANSWER✅✅Decrease peripheral resistance due to vasodilation.
How do thyroid hormones affect the nervous system? - CORRECT ANSWER✅✅Increase alertness,
reflexes, and neural development.
What is the role of TRH in the HPT axis? - CORRECT ANSWER✅✅Stimulates TSH release from the
anterior pituitary.
Where is TRH produced? - CORRECT ANSWER✅✅Hypothalamus.
What is the role of TSH in thyroid hormone regulation? - CORRECT ANSWER✅✅Stimulates thyroid
hormone synthesis and release.
Where is TSH produced? - CORRECT ANSWER✅✅Anterior pituitary thyrotrophs.
How do T3 and T4 regulate the HPT axis? - CORRECT ANSWER✅✅Negative feedback on hypothalamus
and pituitary.
What is the overall function of the hypothalamic-pituitary-thyroid axis? - CORRECT
ANSWER✅✅Maintain stable thyroid hormone levels.
What is thyroid storm? - CORRECT ANSWER✅✅A life-threatening exacerbation of hyperthyroidism with
severe metabolic and cardiovascular symptoms.
, What are common triggers of thyroid storm? - CORRECT ANSWER✅✅Infection, surgery, trauma, or
untreated hyperthyroidism.
What symptoms are seen in thyroid storm? - CORRECT ANSWER✅✅High fever, tachycardia, agitation,
vomiting, and delirium.
What causes exophthalmos in Graves disease? - CORRECT ANSWER✅✅Autoimmune inflammation and
glycosaminoglycan deposition behind the eyes.
What condition is associated with severe hypothyroidism and skin thickening? - CORRECT
ANSWER✅✅Myxedema.
What causes myxedema in hypothyroidism? - CORRECT ANSWER✅✅Accumulation of
glycosaminoglycans in skin and tissues.
What life-threatening complication occurs in severe hypothyroidism? - CORRECT
ANSWER✅✅Myxedema coma.
What are the main drugs used to treat hyperthyroidism? - CORRECT ANSWER✅✅Thionamides,
radioactive iodine, beta-blockers, and iodides.
What are examples of thionamide drugs? - CORRECT ANSWER✅✅Methimazole and propylthiouracil
(PTU).
What enzyme is inhibited by thionamides? - CORRECT ANSWER✅✅Thyroid peroxidase.
What effect does thyroid peroxidase inhibition have? - CORRECT ANSWER✅✅Blocks iodination and
coupling reactions in thyroid hormone synthesis.
Which thionamide also inhibits peripheral T4 to T3 conversion? - CORRECT ANSWER✅✅Propylthiouracil
(PTU).
