Week 3 Review Q's Flashcards
anatomy of thyroid gland (1-40) physio of thyroid hormone actions (41-74) pharma of thyroid disorder treatments (75-104) micro immunepathogenesis of autoimmune diseases of the thyroid (105-134) Thyroid hormone synthesis biochem (135-170) (anatomy) LAB/practical (170-172) Clinical skills slides (173-186) seminar biochem (187-211) pathology of thyroid (212-252) patho lab (253-262)
Which vertebra is the thyroid gland in front of?
C5-T1
During thyroid gland enlargement, where does the thyroid move?
inferiorly
What percent of thyroids have a pyramidal lobe?
50%
Whats a levator glandulae thyroideae?
fibrous/fibromuscular band that stretches from the pyramidal lobe to the body of the hyoid bone above
Which fascia surrounds the thyroid?
pretracheal fascia
Patient comes in with swelling in the neck, it can either be lymph or thyroid swelling. How can you determine the diagnosis?
palpate and ask patient to swallow, it it moves then its a thyroid enlargement
What gives rise to the superior thyroid artery?
external carotid artery
What gives arterial supply to the posterior aspect of the thyroid?
inferior thyroid artery
What gives rise to the inferior thyroid artery?
thyrocervical trunk of Subclavian artery
What gives arterial supply to the anterior aspect of the thyroid?
superior thyroid artery
Where does the Inferior thyroid vein drain into?
Brachiocephalic vein
Where does the middle thyroid vein drain into?
internal jugular vein
What controls the secretion of hormones from the thyroid?
TSH
What controls the blood supply to the thyroid?
Superior, middle, and Inferior cervical sympathatic Ganglion (vasculomotor)
Patient does surgery to correct hyperparathyroidism by removing the thyoid gland. After surgery, their voice becomes harsh due to the inactivity of the cricothyroid muscle. which nerve is affected? a. External laryngeal Nerve b. Recurrent laryngeal nerve
a. External laryngeal Nerve (both laryngeal nerves cause voice changes when damaged)
While trying to remove the superior thyroid which is true? a. Thyroidectomy should be lateral/away from the gland b. Thyroidectomy should be close to the gland
b. Thyroidectomy should be close to the gland
What gives arterial supply to the isthmus of the thyroid?
Thyroid ima
While trying to remove the inferior thyroid which is true? a. Thyroidectomy should be lateral/away from the gland b. Thyroidectomy should be close to the gland
a. Thyroidectomy should be lateral/away from the gland
Patient does surgery to correct hyperparathyroidism by removing the thyoid gland. After surgery, they complain of excessive dryness of mouth? a. External laryngeal Nerve b. Recurrent laryngeal nerve
b. Recurrent laryngeal nerve (mucus membrane supplied by nerve)
parafollicular cell secretion is controlled by
blood calcium levels
What two things can be found in epithelial follicles of the thyroid gland?
colloid and thyroglobulin (paler gelatinous protein)
Which cell lines follicles of the thyroid gland?
follicular cells or thyrocytes
Which cell shape lines follicles of the thyroid gland?
inactive gland = surrounded by squamous active gland = surrounded by columnar or cuboidal
follicular cell secretion is controlled by
TSH
What do C cells secrete?
calcitonin (C cells aka parafollicular cells)
Which of the following appears darker under H&E? a. follicular cells b. parafollicular cells
a. follicular cells
Which of the following appears larger under H&E? a. follicular cells b. parafollicular cells
b. parafollicular cells
What moves iodide to the follicular cell?
Na+/I- symporter
What moves iodide to the colloid?
I-/Cl- transporter aka pendrin
What enzyme transforms iodide to iodine?
thyroperoxidase
in the colloid, one iodine attached to the tyrosine of thyroglobulin. What does this create?
monoiodotyrosine (MIT)
What is produced when a monoiodotyrosine (MIT) and diiodotyrosine (DIT) join together?
triiodothyronine (T3)
What makes it easier to remove the thyroid from the parathyroid?
the thin connective tissue capsule
What two locations is the thyroid derived from?
endoderm and the fifth pharyngeal pouch
in the colloid, two iodines attached to the tyrosine of thyroglobulin. What does this create?
diiodotyrosine (DIT)
What is the origin of parafollicular cells?
they’re from the ultimobranchial body, which is derived from the 5th pharyngeal pouch
Which occurs due to thyroglossal duct remnants? a. thyroglossal cyst b. thyroglossal fistula c. both
c. both
Which is derived from the foramen cecum? a. follicular cells b. parafollicular cells
a. follicular cells
Which is open to the surface/skin? a. thyroglossal cyst b. thyroglossal fistula c. both
b. thyroglossal fistula
A patient who recently had his thyroid removed still has T3 and T4 in his circulation. What can explain this?
accessory thyroid glandular tissue
Besides the thyroid glands, where can T3/4 be found?
liver and kidney (1/3)
Which has a faster turnover rate? a. T3 b. T4 c. both the same
a. T3 (10%/day for T4 versus 70%/day for T3)
Which buffers acute changes in hormone secretion? a. T3 b. T4 c. both
b. T4
Which is biologically active? a. reverse T3 b. T3 c. T4
b. T3
Which is most abundant? a. reverse T3 b. T3 c. T4
c. T4
Which of the following converts T4 to reverse T3? a. Deiodinase type 1 b. Deiodinase type 2 c. Deiodinase type 3 d. A&B
c. Deiodinase type 3 (benov’s note also had D1)
Which enzyme allows iodine to bind to the tyrosine of thyroglobulin?
thyroperoxidase
Describe the concentration of iodine in the plasma versus in the follicular cell
30 times more concentrated in the follicular cell
Which of the following inactivates T4? a. Deiodinase type 1 b. Deiodinase type 2 c. Deiodinase type 3 d. A&B
c. Deiodinase type 3
Which plasma protein do most thyroid hormones bind to?
Thyroxine binding globulin
Which of the following activates T4? a. Deiodinase type 1 b. Deiodinase type 2 c. Deiodinase type 3 d. A&B
d. A&B (T4 to T3)
Which of the following has more T4 binding to it than T3? a. albumin b. thyroxine binding pre-albumin
b. thyroxine binding pre-albumin
Which has a stronger negative inhibition effect? a. reverse T3 b. T3 c. T4
b. T3
Which of the following has more T3 binding to it than T4? a. albumin b. thyroxine binding pre-albumin
a. albumin
Which hormone increases the growth and vascularity of the thyroid gland?
TSH (Iodide salts: Reduces the size and vascularity of hyperplastic thyroid glands)
Young patient with low thyroid hormones has abnormally short stature. Explain the mechanism.
thyroid hormones stimulate growth hormone action and other hormones to promote bone formation
Oxygen consumption of which tissues are not sensitive to thyroid hormones and why?
adult brain, testis, and spleen because they lack mitochondrial TH receptors
Patient had a lack of TSH for a long time. What happened to his thyroid?
atrophy
Explain the mechanism behind tremors in hyperthyroidism
TH interact with the sympathetic branch of the ANS; beta-adrenergic receptor stimulation
What two things stimulate pulmonary surfactant formation?
thyroid hormones and fetal adrenal gland
When is the thyroid hormone are anabolic?
when they have a low physiologic amount, they have a protein anabolic effect decreasing nitrogen excretion
Describe thyroid hormone levels in Hashimoto thyroiditis
initially high levels, but as the destruction of follicular tissue occurs it becomes low
Antibodies against which of the following are called anti microsomal antibodies? a. thyroglobulin b. thyroid peroxidase
b. thyroid peroxidase (aka anti-peroxidase antibodies)
A low IQ in which of the following is reversible? a. Infantile hypothyroidism b. congenital hypothyroidism
a. Infantile hypothyroidism (occurs during childhood; give PTH to reverse it)
Which of the following causes carpal tunnel syndrome? a. hypothyroidism b. hyperthyroidism
a. hypothyroidism
Which of the following is caused by IgG1 antibodies? a. Hashimoto thyroiditis b. Graves disease
b. Graves disease
Which receptor do IgG1 antibodies bind to?
TSH receptors
Which of the following causes pretibial myxoedema? a. hypothyroidism b. hyperthyroidism
b. hyperthyroidism
Which of the following causes a bruit or murmur? a. hypothyroidism b. hyperthyroidism
b. hyperthyroidism
Which of the following causes menorrhagia? a. hypothyroidism b. hyperthyroidism
a. hypothyroidism
Which of the following causes exophthalmos? a. hypothyroidism b. hyperthyroidism
b. hyperthyroidism
Which of the following has low TRH? a. Primary hypothyroidism b. Pituitary hypothyroidism c. Hypothalamic hypothyroidism
c. Hypothalamic hypothyroidism
Which of the following has low TSH? a. Primary hypothyroidism b. Pituitary hypothyroidism c. Hypothalamic hypothyroidism
b. Pituitary hypothyroidism
Describe TRH and TSH values in graves disease
both low
What stimulates the transcription of the Na+/I- symporter gene?
TSH
What is required during the iodide to iodine transformation by thyroperoxidase?
H2O2, Hydrogen peroxide
Which of the following causes hypothyroidism? a. Hashimoto thyroiditis b. Graves disease
a. Hashimoto thyroiditis
What antipsychosis medication causes hypothyroidism?
lithium
Whats the main way that TSH regulates thyroid function?
Uptake of iodide by follicle cells, by stimulating transcription of the iodide transporter genes
Explain why pregnant women are more prone to hypothyroidism
because they produce antibodies to their own thyroid gland
Which of the following can be taken orally? a. Levothyroxine b. Liothyronine c. Liotrix d. all of the above
d. all of the above
Which of the following has a fast peak and a short duration? a. Levothyroxine b. Liothyronine c. Liotrix d. all of the above
b. Liothyronine
A pregnant women (in the last trimester) with low thyroid hormones comes in with high blood pressure that lasted for a week. Whats the possible cause?
hypothyroidism increases the risk of preeclampsia — a condition that causes a significant rise in a woman’s blood pressure during the last three months of pregnancy
Which of the following can be given via IV? a. Levothyroxine b. Liothyronine c. Liotrix d. all of the above
a. Levothyroxine
Liotrix is a mixture of T3 and T4, but at which ratio?
1:4
What kind of drugs are contraindicated in a patient whos taking thyroid hormones?
Drugs that induce CYP450 enzymes because they can accelerate the metabolism of the thyroid hormones and may decrease their effectiveness.
Which of the following is preferred in Myxoedema coma? a. Levothyroxine b. Liothyronine c. Liotrix d. all of the above
b. Liothyronine (Myxedema coma = severe hypothyroidism leading to decreased mental status, hypothermia, and other symptoms related to slowing of function in multiple organs. It is a medical emergency with a high mortality rate.)
How can giving thyroid hormone drugs beneficial in some cancers?
some cancers are TSH-dependent, so giving T3/4 reduces the TSH and helps treat
Which of the following is caused by hyperthyroidism? a. Hashimoto thyroiditis b. Graves disease
b. Graves disease
Which of the following causes more frequent bowl movements? a. hypothyroidism b. hyperthyroidism
b. hyperthyroidism
How many doses of radioactive iodine is given to treat hyperthyroidism?
one dose
What’s the half-life for radioactive iodine?
8 days
What has a longer half-life? a. Methimazole b. Propylthiouracil c. both d. neither
a. Methimazole
Which is preferred in Pregnant women? a. Methimazole b. Propylthiouracil c. both d. neither
b. Propylthiouracil (less likely to cross barriers)
Which inhibits the release of preformed thyroid hormone? a. Methimazole b. Propylthiouracil c. both d. neither
d. neither
Which is mainly used to relief symptoms of hyperthyroidism? a. Iodide salts b. Propylthiouracil c. Propranolol d. Methimazole
c. Propranolol
Which is used to treat thyroid storms? a. Iodide salts b. Propylthiouracil c. Propranolol d. Methimazole
a. Iodide salts (transient effects)
Which TWO inhibit T4 to T3 conversion? a. Iodide salts b. Propylthiouracil c. Propranolol d. Methimazole
b. Propylthiouracil & c. Propranolol
Which causes a metallic taste in the mouth? a. Iodide salts b. Propylthiouracil c. Propranolol d. Methimazole
a. Iodide salts
Which TWO cause hypoprothrombinemia? a. Iodide salts b. Propylthiouracil c. Propranolol d. Methimazole
b. Propylthiouracil & d. Methimazole
Which reduces hyperplastic thyroid gland vascularity? a. Iodide salts b. Propylthiouracil c. Propranolol d. Methimazole
a. Iodide salts
Why do Propylthiouracil & Methimazole need weeks to start working?
because they don’t stop the release of preformed hormones, so in those weeks the body is releasing what it previously made
Which has a lower incidence of side effects? a. Methimazole b. Propylthiouracil
a. Methimazole
Which has a possible adverse effect of tongue or larynx swelling? a. Iodide salts b. Propylthiouracil c. Propranolol d. Methimazole
a. Iodide salts
most autoimmune diseases are a. monogenic b. polygenic
b. polygenic
T/F: autoimmune thyroiditis can cause either hypo/hyperthyroidism, but it always has goiter to go along with it
false, yes it causes hypo/hyperthyroidism but it doesn’t have to have a goiter (some are with some are without)
Which of the following suppresses the immune system? a. IL-23 b. IL-4 c. IL-10 d. IL-15 e. IL-21 f. IL-12
c. IL-10
Which TWO of the following activate Th1? a. IL-23 b. IL-4 c. IL-10 d. IL-15 e. IL-21 f. IL-12
d. IL-15 & f. IL-12
What three proteins are targeted by lymphocyte made antibodies in autoimmune thyroiditis?
Thyroid peroxidase Thyroglobulin Thyroid-stimulating hormone receptor
Which of the following does graves disease cause? a. hypothyroidism b. hyperthyroidism c. both
b. hyperthyroidism
Which of the following does Hashimoto’s thyroiditis cause? a. hypothyroidism b. hyperthyroidism c. both
c. both (hyper initially and hypo eventually)
Which TWO of the following activate Th17? a. IL-23 b. IL-4 c. IL-10 d. IL-15 e. IL-21 f. IL-12
a. IL-23 & e. IL-21
Which is NOT a sign of hypothyroidism? a. periorbital edema b. infertility c. paresthesia d. yellow skin d. proximal muscle weakness
d. proximal muscle weakness (a symptom of hyper)
Which of the following activates Th2? a. IL-23 b. IL-4 c. IL-10 d. IL-15 e. IL-21 f. IL-12
b. IL-4
Why does Hashimoto’s thyroiditis cause hyperthyroidism initially?
the inflammation breaks down the follicles and releases the hormones
Why do patients with Hashimoto’s thyroiditis have low iodine uptake?
Thyroglobulin & Thyroid peroxidase are targeted by autoantibodies. They function to uptake iodine, so when they’re targeted iodine uptake is affected.
Which of the following thyroid antigens are targeted in Graves disease? a. Thyroid peroxidase b. Thyroglobulin c. Thyroid-stimulating hormone receptor
c. Thyroid-stimulating hormone receptor
Which of the following is Hashimoto’s thyroiditis associated with? a. toxic goiter b. lymphocytic infiltration c. subclinical hyperthyroidism d. the presence of anti TSH receptors
b. lymphocytic infiltration (she put this Q in class)
Which of the following increases TSH by increasing follicle size? a. Thyroid-stimulating immunoglobulin b. Thyroid growth immunoglobulin c. Thyroid binding- inhibiting immunoglobulin
b. Thyroid growth immunoglobulin
Which is Th1 predominated? a. Grave’s disease b. Hashimoto’s thyroiditis c. both
b. Hashimoto’s thyroiditis (Th1= cell mediates immunity)
chronic lymphocytic thyroiditis is also called
Hashimoto’s thyroiditis
Which of the following is more likely to be targeted in graves disease? a. Thyroid growth immunoglobulin b. Thyroid-stimulating immunoglobulin c. Thyroid binding- inhibiting immunoglobulin
b. Thyroid-stimulating immunoglobulin
Which has tissue destruction? a. Grave’s disease b. Hashimoto’s thyroiditis c. both
b. Hashimoto’s thyroiditis
What thyroid condition is more common in middle-aged women?
Hashimoto’s thyroiditis
Which has lymphocytic infiltration? a. Grave’s disease b. Hashimoto’s thyroiditis c. both
c. both
Which of the following causes hypothyroidism when attacked? a. Thyroid-stimulating immunoglobulin b. Thyroid growth immunoglobulin c. Thyroid binding- inhibiting immunoglobulin
c. Thyroid binding- inhibiting immunoglobulin
Which is Th2 predominated? a. Grave’s disease b. Hashimoto’s thyroiditis c. both
a. Grave’s disease (Th2= humoral immunity)
autoimmune polyendocrine syndrome (APS) is caused by which gene?
AIRE gene
What mechanism defect causes autoimmune polyendocrine syndrome (APS)?
failure of central tolerance
Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome is caused by which gene?
FOXP3