Bailey Flashcards
The superior parathyroid glands develop from which pharyngeal pouch?
A. Second
B. Third
C. Fourth
D. Fifth
C.
the superior parathyroids develop from the fourth pharyngeal pouch.
The inferior parathyroids develop from the third pharyngeal pouch along with the thymus.
Which of the following structures develop from the third pharyngeal pouch?
(Multiple options correct)
A. Thymus gland
B. Inferior Parathyroid
C. Superior parathyroid
D. Ultimobranchial body
A and B
the inferior parathyroid and thymus both develop from the third pharyngeal pouch.
whereas the ultimobranchial body and the superior parathyroid develop from the 4th pharyngeal pouch.
What is the normal weight of the thyroid gland?
A. 10-15g
B. 15-20g
C. 20-25g
D. 25-30g
C - the normal weight of the thyroid is 20-25g.
Which of the following statements is true regarding anatomy of the thyroid?
A. Normal thyroid gland weighs 10-15g.
B. functioning unit of the thyroid is lobule supplied by multiple arterioles, whereas the follicles are supplied by a single arteriole.
C. each lobule contains 60-80 follicles
D. Follicles are lined with squamous epithelium.
E. the follicle contains colloid in which thyroglobulin is stored.
E. The follicle contains colloid in which thyroglobulin is stored.
- Normal gland weighs 20-25g.
- lobule is the functioning unit and it is supplied by a single arteriole.
- each lobule contains 24-40 follicles, NOT 60-80.
- the follicles are lined by cuboidal epithelium NOT squamous.
what percentage of the RLN on the right side are non-recurrent and enter the larynx from above?
A. 2%
B. 5%
C. 8%
D. 10%
A. 2% of the recurrent laryngeal nerves on the right are non-recurrent and enter the larynx from above.
RLN is a branch of the vagus that recurs around the arch of aorta on the left and the subclavian artery on the right.
Maximum risk of the injury to the RLN during surgery is at which point?
A. at the cricothyroid joint
B. level of Berry’s ligament
C. Tracheo-esophageal groove
D. Both A and B
A and B - the maximum risk of injury to the RLN during surgery is at the entry point of the larynx at the cricothyroid joint which lies at the level of Berry’s ligament.
which of the following is not a boundary of the Beahr’s triangle?
A. Recurrent Laryngeal Nerve
B. Tubercle of Zuckerkandl
C. Carotid Artery
D. Inferior thyroid artery
B. Tubercle of Zuckerkandl
the Beahr’s triangle is formed by the RLN in the TE-groove along with inferior thyroid artery and carotid artery.
Tubercle of Zuckerkandl - is the most posterolateral portion of the gland, lying below the which the RLN can often be found in the TE groove as the gland is mobilized laterally.
Arrange the following steps of thyroxine production in the correct order.
- oxidation of iodide
- coupling of monoiodotyrosine and di-iodotyrosine to form T3 and T4.
- Trapping of inorganic iodine from the blood
- Binding of iodine with tyrosine to iodotyrosine
- resorption of thyroglobulin complex into the cell and breakdown.
A. 4-2-1-3-5
B. 3-1-4-2-5
C. 3-1-2-4-5
D. 1-3-2-4-5
B. 3-1-4-2-5
a - Trapping of inorganic iodine from blood
b -Oxidation of iodide
c - Binding of iodine with tyrosine to form iodotyrosine
d - couping of monoiodotyrosine and di-iodotyrosine to form T3 and T4.
e - resorption of the thyroglobulin complex into the cell and breakdown.
thyroxine is bound to all of the following in blood except -
A. Albumin
B. TBPA
C. Thyroglobulin
D. TBG
ans C -
in blood thyroxine is bound to albumin, Thyroid binding pre-albumin (TBPA), thyroid binding globulin (TBG).
Thyroglobulin complex is present in the colloid within the gland.
what percentage of T4 and T3 remains unbound or free in circulation, and therefore active -
A. 0.01% and 0.1%
B. 1% and 0.1%
C. 0.03% and 0.3%
D. 0.3% and 0.1%
Ans - C.
- 03% of thyroxine of T4 remains free or unbound or fT4
- 3% of the T3 remains free or unbound or fT3
what is the average duration of action of T4.
A. few minutes
B. few hours
C. few days
D. few months
Ans C -
T4 is slow acting and remains active for 4-14 days.
T3 is fast acting and acts within few hours.
what is the normal level of TSH?
A. 0.1 to 1.1 mU/L
B. 0.2 to 2.2 mU/L
C. 0.3 to 3.3 mU/L
D. 7 to 9 mU/L
Ans C -
normal levels of TSH - 0.3 to 3.3 mU/L
What is the normal level of fT4 in serum?
A. 1 to 10 nmol/L
B. 10-30 nmol/L
C. 30-60 mmol/L
D. 90-100 nmol/L
Ans - B
10-30 nmol/L
what is the normal level of fT3 in serum?
A. 1.5-3.5 umol/L
B. 3.5-7.5 umol/L
C. 7.5-10 umol/L
D. 10-12.5 umol/L
Ans B -
3.5 to 7.5 umol/L
A patient presents with undetectable TSH, with fT4 45 nmol/L and fT3 of 5 umol/L.
What could be the possible cause?
A. Hypothyroidism
B. Suppressive T4 therapy
C. thyrotoxicity
D. T3 toxicity
Ans B - supressive T4 therapy
undetectable TSH with raised fT4 (normal levels are 10-30 nmol/L) and normal or raised fT3 (3.5-7.5 umol/L) is suggestive of supressive T4 therapy.
which of the following statements is TRUE regarding the thyroid stimulating antibodies or TRAbs?
A. they belong the IgM class of immunoglobulins
B. they are responsible for virtually all cases of thyrotoxicosis other than autonomous toxic nodules
C. they have a duration of action of 1.5-3 hours on TSH receptors
D. their measurement is necessary to make the diagnosis.
E. they are largely produced in the serum
Ans B - they are responsible for virtually all cases of thyrotoxicosis other than autonomous toxic nodules.
- they belong to IgG class.
- TSH acts for 1.5 to 3 hours, whereas TRAbs act for longer duration - 16-24 hours.
- their measurement is NOT necessary to make the diagnosis.
- they are largely produced in the thyroid itself.
Bailey 27e pg 802, 803.
What are the levels above which TPO antibodies are considered positive ?
A. 10 U/mL
B. 15 U/mL
C. 20 U/mL
D. 25 U/mL
ans D - 25 U/mL
Serum levels of antibodies against Thyroid peroxidase and thyroglobulin are useful in determining the cause of thyroid dysfunction and swellings.
Autoimmune thyroiditis may be associated with thyroid toxicity, thyroid failure or euthyroid goitre.
Bailey 27 e pg 803.
What are the titres of Anti-thyroglobulin which are considered significant -
A. 1:10
B. 1:100
C. 1:1000
D. 1:10000
Ans B -
Titres of anti-thyroglobulin greater than 1:100 are considered significant.
The presence of anti-thyroglobulin antibodies interferes with the assays of serum thyrogobulin and thus have implications in follow up of thyroid cancers.
Bailey 27e pg 803.
Which of the following is considered the workorse investigation in case of thyroid disease
A. TSH
B. USG
C. FNAC
D. TRab
ans B - USG is considered the workhorse investigation in thyroid disease.
Bailey 27e Pg 803.
Imaging modality of choice for retrosternal extension of goitre ?
A. USG
B. X ray Chest
C. CT Chest
D. MRI
ans C - CT chest is the investigation of choice for retrosternal extension as well as when metastatic disease is detected.
Bailey 27e Pg 803
Best investigation to comment upon invasion of the pre-vertebral fascia in thyroid cancer ?
A. USG
B. CT
C. MRI
D. Radioisotope scintigraphy
Ans - MRI is superior in determining presence of prevertebral fascia invasion.
CT is useful for determining the extent of airway invasion.
Bailey 27e Pg 803.
What percentage of ‘cold’ and ‘warm’ thyroid nodules are malignant?
A. 80% cold, 5% warm
B. 20% cold, 5% warm
C. 20% cold, 1 % warm
D. 80% cold, 1% warm
ans B - 20% cold and 5% warm.
Bailey 27e Pg 804.
investigation of choice in discrete thyroid swellings?
A. FNAC
B. USG
C. CT
D. Radioisotope scintigraphy
Ans A - FNAC
Bailey 27e Pg 804.
As per the British Thyroid associated classification for FNA in thyroid swellings, non-neoplastic is ?
A. Thy 1 B. Thy 2 C. Thy 3 D. Thy 4 E. Thy 5
ans B - Thy 2 is considered non-neoplastic.
As per the british thyroid association classification for FNA -
Thy 1 - nondiagnostic Thy 1c - nondiagnostic cystic Thy 2 - non-neoplastic Thy 3 - Follicular Thy 4 - Suspicious for malignancy Thy 5 - malignant.
Bailey 27e pg 805.