Thyroid Gland

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What is the main storage of the thyroid hormones within the thyroid gland?

Follicular cells

Colloid (correct)

Glandular cells

Thyroglobulin

Where are the thyroid glands located in most mammals?

Caudal to the esophagus

Cranial to the esophagus

Caudal to the trachea at the level of the first or second tracheal ring (correct)

Cranial to the trachea

Which of the following is NOT a function of the thyroid hormones?

Regulating body temperature (correct)

Promoting growth and development

Regulating blood calcium levels

Regulating metabolic rate

What is the half-life of thyroxine?

7-10 days Signup and view all the answers

Which type of cells in the thyroid gland synthesize the thyroid hormones?

Follicular cells Signup and view all the answers

Which of the following is NOT a type of amine hormone?

Insulin Signup and view all the answers

Which of the following is NOT a physiological action of thyroid hormones?

Increase blood flow and cardiac output Signup and view all the answers

What is the minimal rate of energy expenditure per unit time at rest called?

Basal metabolic rate Signup and view all the answers

Which of the following is NOT a metabolic effect of thyroid hormones?

Increase cellular uptake and degradation of LDL Signup and view all the answers

What is the main cause of hyperthyroidism in cats?

Tumors of the thyroid gland Signup and view all the answers

What is the main symptom of hypothyroidism in dogs?

Lethargy and obesity Signup and view all the answers

What is the primary cause of hypothyroidism in dogs?

Lymphocytic thyroiditis Signup and view all the answers

What is the major substrate that combines with iodine to form thyroid hormones?

Tyrosine Signup and view all the answers

Where does iodine come from in the thyroid hormone synthesis process?

It is converted from iodide in the intestinal tract Signup and view all the answers

Which cells secrete calcitonin?

Parafollicular cells Signup and view all the answers

How do thyroid follicle cells trap iodide?

Active transport process Signup and view all the answers

What is the intracellular concentration of iodide compared to the extracellular concentration in the thyroid follicle cells?

Higher Signup and view all the answers

What enzyme is responsible for the synthesis of thyroid hormones in the thyroid follicle lumen?

Thyroid peroxidase Signup and view all the answers

Which of the following is the correct sequence of events in the production of thyroid hormones?

Organification, tyrosine iodination, coupling Signup and view all the answers

What is the result of the fusion of two iodinated tyrosines?

T4 or Thyroxine Signup and view all the answers

What is the major hormone produced by the follicular cells?

T4 Signup and view all the answers

Where are T3 and T4 stored before secretion?

In the colloid Signup and view all the answers

How are thyroid hormones transported in the blood?

Attached to thyroxine-binding globulin (TBG) and albumin Signup and view all the answers

What is the primary function of thyroid hormones?

Control of metabolism Signup and view all the answers

Which gland typically enlarges due to iodine deficiency?

Thyroid gland Signup and view all the answers

What are the compounds that interfere with iodine uptake by the thyroid gland or with normal synthesis of thyroid hormones called?

Goitrogens Signup and view all the answers

Which tests can be used for the diagnosis of endocrine disorders?

All of the above Signup and view all the answers

Which hormone suppression test is used to evaluate thyroid function?

T3 suppression test Signup and view all the answers

Which of the following is NOT a factor that can lead to iodine deficiency?

Excessive iodine intake Signup and view all the answers

What is the role of goitrogens in the development of goiter?

They inhibit iodine uptake by the thyroid gland Signup and view all the answers