thyroid Flashcards
Which of the following is true?
A Most cats lack a cranial thyroid artery, and utilize the caudal thyroid artery
B Lymphatic drainage is caudal and goes to the sternal lymph nodes
C The laryngeal recurrent nerves are dorsal and usually medial to the thyroid glands
D The cranial thyroid artery is a branch of the brachiocephalic artery
A caudal absent
B LN cranial (deep cervical or medial retropharyngeal)
C true
D common carotid –> cranial thyroid artery
brachiocephalic –> caudal
Which of the following is true regarding parathyroid?
A Ectopic parathyroid tissue is more common than ectopic thyroid tissue
B Ectopic parathyroid tissue has been detected histologically in 35-50% of dogs
C The internal parathyroid gland is more caudal than the external parathyroid gland
D Parathyroid tissue can always be found at the same location
A thyroid> parathyr
B cats 35-50% (dogs 3-6%)
C true
D variable location, number and distribution
what is another name for thyroxine?
T4
triiodothyronine = T3
True/false: The portein bound T3 and T4 enables the hormones to enter the cells and produce their metabolic effects
False: protein-bound = storage pool. Free thyroid homes enter cells
True/false: Only free hormones (primarily T3) regulate the pituitary feedback to inhibit TSH secretion
true
What are the effects of PTH?
increase Ca concentration and decrease Phosphorus concentration in the blood
also increases formation of calcitriol
true/false: Calcitriol is produced by thyroid gland parafollicular cells (c-cells) and help prevent postprandial hypercalcemia in mammals
False: Calcitonin –> prevent hypercalcemia
1,25-dihydroxycholecalciferol = calcitriol –> increases absorption of Ca and P from intestine
Where is the lymphatic drainage of the thyroid?
Cranial
What artery nerve and vein travels in the carotid sheath?
vagosympathetic trunk
common carotid
internal jugular vein
how is the thyroid innervated?
vagus –> thyroid nerve
Where does the recurrent laryngeal nerve live in relation to the thyroid glands?
Dorsal and medial
The pararecurrent and pharyngoesophageal nerves are less important
What is the source of the cranial thyroid artery? the caudal thyroid artery?
veins?
common carotid –> cranial T
Brachycephalic trunk –> Caudal T In DOGS
cranial + caudal to internal jugular (sometimes caudal –> brachiocephalic trunk)
Most common complication with bilateral thyroidectomy in cat with hyperthyroid done with intracapsular technique?
recurrence of hyperthryoidism if intracapsular since will leave microscopic dz
(not hypothyroidism)
What percentage of T3 is derived from the monodeiodination of T4 in peripheral tissues?
40-60%
What is another name for 1,25-dihydroxycholecalciferol?
calcitriol
