ABSITE Thyroid Gland UPDATED
ACTUAL Exam Questions and CORRECT
Answers
thyroid source - CORRECT ANSWER - 1st and 2nd pharyngeal ARCHES (not pouches)
thyroid hormone pathway - CORRECT ANSWER - TRF (hypothal) ---> TSH (anterior
pituitary) ---> T3 and T4 release from thyroid (through mechanism that involved inc cAMP) --->
negative feedback loop to TRF and TSH
thyroid arterial supply - CORRECT ANSWER - (1) superior thyroid artery = 1st branch
from external carotid ... (2) inferior thyroid artery = off thyrocervical trunk (branch of
subclavian), supplies BOTH inferior and superior parathyroids, **ligate close to thyroid to avoid
injury to parathyroid glands in thyroidectomy ... (3) Ima artery = occurs in 1%, arise from
innominate or aorta and goes to isthmus
thyroid venous drainage - CORRECT ANSWER - superior and middle thyroid veins =
drain into IJ vein .... inferior thyroid vein = drains into innominate vein
how to avoid parathyroid complications in thyroidectomy - CORRECT ANSWER - ligate
close to thyroid to avoid injury to parathyroid glands in thyroidectomy .... inferior thyroid artery
= off thyrocervical trunk (branch of subclavian), supplies thyroid and inferior and superior
parathyroids
thyroid innervation: name - CORRECT ANSWER - superior laryngeal nerve and recurrent
laryngeal nerves (RLNs)
thyroid innervation: function - CORRECT ANSWER - superior = motor to cricothyroid
muscle .... RLN = motor to all larynx except cricothyroid muscle
thyroid innervation: describe course and surrounding structures - CORRECT ANSWER -
superior = runs LATERAL to thyroid lobes, tracks close to superior thyroid artery but is variable
, ... RLN = runs POSTERIOR to thyroid lobes in tracheoesophageal groove, tracks with inferior
thyroid artery but variable
thyroid innervation: injury leads to what? - CORRECT ANSWER - superior = loss of
projection and easy voice fatigue (classic ex is opera singer) ... RLN = hoarseness, b/l can
obstruct airway and may need emergent airway
thyroid innervation: describe RLN locations - CORRECT ANSWER - L loops around
aorta vs R loops around innominate artery
thyroid innervation: describe RLN variations - CORRECT ANSWER - non-recurrent
laryngeal nerve in 2%, more common on R ... risk of injury is higher for a non-recurrent
laryngeal nerve during thyroid surgery
ligament of berry - describe - CORRECT ANSWER - posterior medial suspensory
ligament close to RLNS, needs careful dissection
thyroblogulin - function, types and relative amnts and production - CORRECT
ANSWER - stores T3 and T4 in colloid ... plasma T4:T3 ratio is 15:1 .... T3 is the more
active form (tyrosine + iodine) ... most T3 is made in periphery from T4 to T3 conversion by
deiodinases
peroxidase and deiodinase functions - CORRECT ANSWER - peroxidase = link iodine
and tyrosine together (form T3, more active form) .... deiodinase = separate iodine from tyrosine
thyroxine-binding globulin function - CORRECT ANSWER - thyroid hormones transport,
binds majority of T3 and T4 in circulation
measure thyroid gland function - CORRECT ANSWER - TSH is the most sensitive
indicator
ACTUAL Exam Questions and CORRECT
Answers
thyroid source - CORRECT ANSWER - 1st and 2nd pharyngeal ARCHES (not pouches)
thyroid hormone pathway - CORRECT ANSWER - TRF (hypothal) ---> TSH (anterior
pituitary) ---> T3 and T4 release from thyroid (through mechanism that involved inc cAMP) --->
negative feedback loop to TRF and TSH
thyroid arterial supply - CORRECT ANSWER - (1) superior thyroid artery = 1st branch
from external carotid ... (2) inferior thyroid artery = off thyrocervical trunk (branch of
subclavian), supplies BOTH inferior and superior parathyroids, **ligate close to thyroid to avoid
injury to parathyroid glands in thyroidectomy ... (3) Ima artery = occurs in 1%, arise from
innominate or aorta and goes to isthmus
thyroid venous drainage - CORRECT ANSWER - superior and middle thyroid veins =
drain into IJ vein .... inferior thyroid vein = drains into innominate vein
how to avoid parathyroid complications in thyroidectomy - CORRECT ANSWER - ligate
close to thyroid to avoid injury to parathyroid glands in thyroidectomy .... inferior thyroid artery
= off thyrocervical trunk (branch of subclavian), supplies thyroid and inferior and superior
parathyroids
thyroid innervation: name - CORRECT ANSWER - superior laryngeal nerve and recurrent
laryngeal nerves (RLNs)
thyroid innervation: function - CORRECT ANSWER - superior = motor to cricothyroid
muscle .... RLN = motor to all larynx except cricothyroid muscle
thyroid innervation: describe course and surrounding structures - CORRECT ANSWER -
superior = runs LATERAL to thyroid lobes, tracks close to superior thyroid artery but is variable
, ... RLN = runs POSTERIOR to thyroid lobes in tracheoesophageal groove, tracks with inferior
thyroid artery but variable
thyroid innervation: injury leads to what? - CORRECT ANSWER - superior = loss of
projection and easy voice fatigue (classic ex is opera singer) ... RLN = hoarseness, b/l can
obstruct airway and may need emergent airway
thyroid innervation: describe RLN locations - CORRECT ANSWER - L loops around
aorta vs R loops around innominate artery
thyroid innervation: describe RLN variations - CORRECT ANSWER - non-recurrent
laryngeal nerve in 2%, more common on R ... risk of injury is higher for a non-recurrent
laryngeal nerve during thyroid surgery
ligament of berry - describe - CORRECT ANSWER - posterior medial suspensory
ligament close to RLNS, needs careful dissection
thyroblogulin - function, types and relative amnts and production - CORRECT
ANSWER - stores T3 and T4 in colloid ... plasma T4:T3 ratio is 15:1 .... T3 is the more
active form (tyrosine + iodine) ... most T3 is made in periphery from T4 to T3 conversion by
deiodinases
peroxidase and deiodinase functions - CORRECT ANSWER - peroxidase = link iodine
and tyrosine together (form T3, more active form) .... deiodinase = separate iodine from tyrosine
thyroxine-binding globulin function - CORRECT ANSWER - thyroid hormones transport,
binds majority of T3 and T4 in circulation
measure thyroid gland function - CORRECT ANSWER - TSH is the most sensitive
indicator
