previous year question on pharyngeal arches embryology based on neet pg, usmle, plab and fmge or mci...

Thyroid medullary cells that produce calcitonin develop from:

A: Ultimobranchial bodyB: Floor of the primitive pharynxC: 3rd pharyngeal archD: Lung buds

Correct Ans:AExplanation

Neural crest derivatives from the ultimobranchial body give rise to thyroid medullary C cells.It produces calcitonin. The C cells are interspersed throughout the thyroid gland.

ALSO KNOWThe ultimobranchial body arises from bilateral ventral swellings of the 4th pharyngeal pouches and gets integrated into the thyroid where it forms the parafollicular cells or C-cells for the production of calcitonin.

Ref: Harrison, E-18, P-2911.

Sample Previous Year Question on Embryology (Pharyngeal Arches) based on previous Year Questions of NEET PG, USMLE,PLAB,FMGE (MCI Screening). Please visit www.medicoapps.org for more such Quizzes

Which of the following pharyngeal arch give rise to epiglottis in embryological life?

A: 1st pharyngeal archB: 2nd pharyngeal archC: 3rd pharyngeal archD: 4th pharyngeal archCorrect Ans:DExplanation

The hypobranchial eminence, derived from the bases of the third and fourth pharyngeal arches, forms the epiglottis. Pharyngeal and laryngeal muscles, laryngeal skeleton, cranial nerve X are derived from fourth and sixth pharyngeal arches.

Ref: A Textbook of Neuroanatomy By Maria Patestas, Leslie P. Gartner, 2009, 6.


A 17-year-old male is examined by a physician, who notes a mass at the back of the young man's tongue. The physician biopsies the mass, and the pathology report comes back with a diagnosis of normal thyroid tissue. The occasional presence of such tissue at the back of the tongue is related to the embryonic origin of the thyroid near which of the following structures?

A: First pharyngeal pouchB: Foramen cecum

C: Nasolacrimal ductD: Second pharyngeal archCorrect Ans:BExplanation

The thyroid gland originates as a mass of endodermal tissue near the foramen cecum, which is near the tuberculum impar (which becomes the central part of the tongue). During development, the thyroid descends in front of the pharynx, maintaining a connection to the tongue via the thyroglossal duct.

Usually, the thyroglossal duct disappears. Uncommonly, residual ectopic thyroid tissue can be left anywhere along the path, including at the back of the tongue. (In rare patients, all of the thyroid tissue remains at this site, forming a mass that should not be excised, for obvious reasons!).

The first pharyngeal pouch develops into the middle ear and eustachian tube. The nasolacrimal ducts connect the eyes to the mouth. The second pharyngeal arch develops into many muscles of the face and styloid process of the temporal bone.


A 17-year-old male is examined by a physician, who notes a mass at the back of the young man's tongue. The physician biopsies the mass, and the pathology report comes back with a diagnosis of normal thyroid tissue. The occasional presence of such tissue at the back of the tongue is related to the embryonic origin of the thyroid near which of the following structures?

A: First pharyngeal pouchB: Foramen cecum

C: Nasolacrimal duct

D: Second pharyngeal archCorrect Ans:BExplanation

The thyroid gland originates as a mass of endodermal tissue near the foramen cecum, which is near the tuberculum impar (which becomes the central part of the tongue). During development, the thyroid descends in front of the pharynx, maintaining a connection to the tongue via the thyroglossal duct.

Usually, the thyroglossal duct disappears. Uncommonly, residual ectopic thyroid tissue can be left anywhere along the path, including at the back of the tongue. (In rare patients, all of the thyroid tissue remains at this site, forming a mass that should not be excised, for obvious reasons!).

The first pharyngeal pouch develops into the middle ear and eustachian tube. The nasolacrimal ducts connect the eyes to the mouth. The second pharyngeal arch develops into many muscles of the face and styloid process of the temporal bone.


Which of the following pharyngeal arches develops into epiglottis?

A: 1st pharyngeal archB: 2nd pharyngeal archC: 4th pharyngeal archD: 3rd pharyngeal archCorrect Ans:CExplanation

Pharyngeal arch Muscular contributions Skeletal contributions

1st (also called "mandibular arch")

Muscles of mastication, anterior belly of the digastric, mylohyoid, tensor tympani, tensor veli palatini

Maxilla, mandible (only as a model for mandible not actual formation of mandible), the incus and malleus of the middle ear, also Meckel's cartilage

2nd (also called the "hyoid arch")

Muscles of facial expression, buccinator, platysma, stapedius, stylohyoid, posterior belly of the digastric

Stapes, styloid process, hyoid (lesser horn and upper part of body), Reichert's cartilage

3rd Stylopharyngeus Hyoid (greater horn and lower part of body), thymus, inferior parathyroids

4th Cricothyroid muscle, all intrinsic muscles of soft palate including levator veli palatini

Thyroid cartilage, superior parathyroids, epiglottic cartilage

6th All intrinsic muscles of larynx except the cricothyroid muscle

Cricoid cartilage, arytenoid cartilages, corniculate cartilage

Ref: Langman Embryology, 11 Edition, pg. 277


Intrinsic muscles of the tongue are derived from:

A: 2nd branchial cleftB: Pharyngeal arch mesenchymeC: Occipital somitesD: Cervical somites

Correct Ans:CExplanationThe occipital somites (four to five) give rise to muscles of the tongue. The tongue's embryonic origin is derived from first 4 pharyngeal arches contributing different components. Anterior 2/3rd or body of tongue is derived from 3 lingual buds the median tongue bud (tuberculum impar) and 2 lateral lingual swellings developing at each side of the median tongue bud. 2/3rd of the tongue originates from the first pharyngeal arch.

Sensory innervation to this area is by the mandibular branch of the trigeminal nerve. (Taste sensation to the anterior 2/3rd of the tongue is provided by the chorda tympani branch of the facial nerve). Post 1/3rd or root of the tongue is formed from two median elevations.

Ref: Human Embryology INDERBIR SINGH 6th Ed Page 98,156.


previous year question on pharyngeal arches embryology based on neet pg, usmle, plab and fmge or mci...

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