Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ INTRODUCTION ++ Test Taking Tips Aldosterone, electrolyte, and acid-base imbalances in adrenal disease are popular testing topics. The MEN syndromes are also a favorite topic. Know these well, and understand when to operate and what operation to perform! +++ THYROID +++ EMBRYOLOGY, ANATOMY, AND PHYSIOLOGY +++ What embryologic structures does the thyroid originate from? ++ The medial thyroid comes from the first and second pharyngeal pouches Lateral portions of the thyroid and parafollicular C cells arise from the fourth and fifth pharyngeal pouches ++ FIGURE 12-1 Anatomy of the thyroid gland and surrounding structures, viewed anteriorly. a., artery; n., nerve; v., vein. (Reproduced with permission from Brunicardi FC, Andersen DK, Billiar TR, et al. Schwartz’s Principles of Surgery, 11th ed. New York, NY: McGraw Hill; 2019.) Graphic Jump LocationView Full Size||Download Slide (.ppt) +++ What is the arterial supply of the thyroid? ++ Superior thyroid artery (from external carotid artery) Inferior thyroid artery (from thyrocervical trunk) +++ What is the venous drainage of the thyroid? ++ Superior and middle thyroid veins (drain into internal jugular vein) Inferior thyroid veins (drain into innominate and brachiocephalic veins) +++ The recurrent laryngeal nerve innervates all of the muscles of the larynx except this muscle: ++ Cricothyroid muscle, which is innervated by the external branch of the superior laryngeal nerve +++ What structures do the recurrent laryngeal nerves wrap around? ++ Subclavian artery on the right Arch of the aorta on the left +++ Injury to which nerve results in loss of projection and voice fatigability? ++ Superior laryngeal nerve +++ DRUGS +++ What is the mechanism of action of propylthiouracil (PTU) and methimazole? ++ Both drugs block peroxidase oxidation of iodide to iodine, thereby inhibiting incorporation of iodine into T4 and T3 PTU also inhibits peripheral conversion of T4 to T3 +++ Which drug crosses the placenta: PTU or methimazole? ++ Methimazole PTU is the safer choice in pregnancy +++ When steroids are given in severe or acute hyperthyroid conditions, how do they work? ++ Steroids inhibit peripheral conversion of T4 to T3 and lower serum TSH by suppressing the pituitary-thyroid axis +++ What is the Wolff-Chaikoff effect? ++ Large doses of iodine given after an antithyroid medication can inhibit thyroid hormone release by disrupting the coupling of iodide. This is a transient effect. +++ HYPERTHYROIDISM/HYPOTHYROIDISM AND GOITERS +++ What are the 3 most commons cause of hyperthyroidism? ++ Graves disease, ... Your Access profile is currently affiliated with [InstitutionA] and is in the process of switching affiliations to [InstitutionB]. Please select how you would like to proceed. Keep the current affiliation with [InstitutionA] and continue with the Access profile sign in process Switch affiliation to [InstitutionB] and continue with the Access profile sign in process Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Error: Incorrect UserName or Password Username Error: Please enter User Name Password Error: Please enter Password Sign in Forgot Password? Forgot Username? Sign in via OpenAthens Sign in via Shibboleth You already have access! Please proceed to your institution's subscription. Create a free profile for additional features.