Thyroid Hormone Synthesis and Regulation

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What is the primary function of peroxidase enzymes in the synthesis of thyroid hormones?

To produce thyroxine-binding globulins

To regulate the release of thyroid hormones into the bloodstream

To cleave T3 and T4 from thyroglobulin

To mediate the attachment of iodine to tyrosine (correct)

What is the result of inadequate iodine intake on the thyroid gland?

The thyroid gland atrophies

The thyroid gland enlarges and protrudes (correct)

The thyroid gland produces excessive amounts of T3 and T4

The thyroid gland stops producing thyroid hormones

What is the primary cause of cretinism or congenital hypothyroidism?

Hyperthyroidism during infancy

Thyroid gland atrophy

Genetic deficiency or maternal factors (correct)

Iodine deficiency during pregnancy

What is the primary symptom of exophthalmos in Grave's disease?

Protrusion of the eyeballs Signup and view all the answers

What is the primary mechanism of negative feedback in regulating thyroid hormone levels?

Thyroid hormones inhibit the production of TRH Signup and view all the answers

What is the primary treatment for myxedema?

Iodine supplements or hormone replacement therapy Signup and view all the answers

What is the primary cause of hyperthyroidism in Grave's disease?

Production of antibodies that mimic TSH Signup and view all the answers

What is the primary function of thyroxine-binding globulins (TBGs)?

Bind to T3 and T4, regulating their levels Signup and view all the answers

What is the primary role of testosterone in the male reproductive system?

Maturation of male reproductive organs and development of secondary sexual characteristics Signup and view all the answers

Which hormone produced by the heart reduces blood pressure, blood volume, and blood sodium concentration?

Atrial natriuretic peptide (ANP) Signup and view all the answers

What is the primary function of enteroendocrine cells in the gastrointestinal tract?

Release of local-acting digestive hormones Signup and view all the answers

Which structure produces human chorionic gonadotropin (hCG) during pregnancy?

Placenta Signup and view all the answers

What is the primary role of leptin in the body?

Involved in the sensation of satiety and stimulation of increased energy expenditure Signup and view all the answers

Which hormone-producing glands arise from the mesoderm?

Those that produce steroid hormones Signup and view all the answers

What is the primary function of cholecalciferol in the body?

Precursor of vitamin D Signup and view all the answers

Which hormone-producing structure is responsible for the development of secondary sexual characteristics in females?

Ovaries Signup and view all the answers

Which part of the adrenal gland secretes epinephrine in response to sympathetic stimulation?

Adrenal medulla Signup and view all the answers

What is necessary for the synthesis of aldosterone?

Aldosterone synthase Signup and view all the answers

What hormone does the middle layer of the adrenal cortex secrete?

Cortisol Signup and view all the answers

Which hormones are secreted by the adrenal medulla?

Epinephrine and norepinephrine Signup and view all the answers

From what are corticosteroids synthesized?

Cholesterol Signup and view all the answers

Which part of the adrenal gland is related to the sympathetic nervous system?

Adrenal medulla Signup and view all the answers

What does the deep layer of the adrenal cortex secrete?

Adrenal androgens and small amounts of estrogens and glucocorticoids Signup and view all the answers

What can be a result of a parathyroid gland tumor?

All of the above Signup and view all the answers

Which symptom is not typically associated with hypersecretion of the sympathetic nervous system?

Bradycardia Signup and view all the answers

Which statement best describes the function of glucagon secreted by the pancreas?

Increases blood glucose levels Signup and view all the answers

What is the primary function of melatonin in the human body?

Regulates day/night cycles Signup and view all the answers

Which cells in the pancreatic islets are responsible for insulin secretion?

Beta cells Signup and view all the answers

Which of the following describes the pineal gland's location?

In the roof of the third ventricle Signup and view all the answers

Which function is directly influenced by melatonin?

Resetting biological clock Signup and view all the answers

What is the primary role of the acinar cells in the pancreas?

Production of digestive juices Signup and view all the answers

Which process is NOT stimulated by the hormone glucagon?

Reduction of blood glucose levels Signup and view all the answers

What is one of the primary actions of calcitonin on the skeleton?

Inhibits osteoclast activity Signup and view all the answers

Which cells are responsible for the synthesis and secretion of calcitonin?

Parafollicular cells Signup and view all the answers

How does PTH increase calcium levels in the blood?

By increasing the absorption of calcium by intestinal mucosal cells Signup and view all the answers

Which statement describes the primary regulation mechanism for calcitonin secretion?

A negative feedback mechanism based on blood calcium levels Signup and view all the answers