Embryology Unit 2

Home , Ectopic thymus, Thyroglossal duct

Unit 2 Embryology Clinically Oriented Anatomy (COA)

Texas Tech Health Sciences Center Created by Jake Sellers, Fall 2019 jake.sellers@uhsc.edu Soluons

1. E 11.B 21.A 2. D 12.C 22.D 3. B 13.E 23.C 4. B 14.A 24.E 5. C 15.D 25.B 6. D 16.A 7. B 17.C 8. D 18.B 9. B 19.E 10.E 20.B

Pharyngeal Apparatus Queson #1: With respect to pharyngeal arches, which of the following can neural crest cells diﬀerenate into?

A. Nerves B. Bone C. Arteries D. All of the above E. A and B

Queson #1:

A. Nerves B. Bone C. Arteries: mesoderm diﬀerenates into muscles and arteries D. All of the above E. A and B: neural crest cells diﬀerenate into nerves, bone and connecve ssue

Queson #2: Which of the following embryonic structures are obliterated during development?

A. Pharyngeal arch 3 B. Pharyngeal arch 4 C. Pharyngeal membrane 1 D. Pharyngeal arch 5 E. Pharyngeal groove 1 Queson #2:

A. Pharyngeal arch 3 B. Pharyngeal arch 4 C. Pharyngeal membrane 1 D. Pharyngeal arch 5: Pharyngeal arch 5, grooves & membranes 2, 3, and 4 are all obliterated E. Pharyngeal groove 1

Queson #3: Which of the following structures are derived from pharyngeal arch 1?

A. Cricoid carlage B. Incus C. Stapes D. Tympanic cavity E. Epithelial lining of auditory tube Queson #3:

A. Cricoid carlage: Derived from pharyngeal arch 6 B. Incus: Derived from pharyngeal arch 1 C. Stapes: Derived from pharyngeal arch 2 D. Tympanic cavity: Derived from pharyngeal membrane 1 E. Epithelial lining of auditory tube: Derived from pharyngeal pouch 1

Queson #4: Which of the following pharyngeal arches is the posterior belly of the digastric muscle derived from? A. Pharyngeal arch 1 B. Pharyngeal arch 2 C. Pharyngeal arch 3 D. Pharyngeal arch 4 E. Pharyngeal arch 6 Queson #4:

A. Pharyngeal arch 1: Muscles of mascaon, mylohyoid, anterior belly of the digastric muscle, tensor tympani, tensor veli palani B. Pharyngeal arch 2: Posterior belly of the digastric muscle, facial expression muscles, stylohyoid, stapedius C. Pharyngeal arch 3: Stylopharyngeus D. Pharyngeal arch 4: Cricothyroid, most so palate muscles, most pharynx muscles E. Pharyngeal arch 6: Most intrinsic larynx muscles, upper esophageal muscle

Queson #5: Which of the following structures are derived from pharyngeal arch 3?

A. Stapes B. Upper ½ hyoid C. Lower ½ hyoid D. Thyroid carlage E. Cuniform carlage Queson #5:

A. Stapes: Derived from pharyngeal arch 2 B. Upper ½ hyoid: Derived from pharyngeal arch 2 C. Lower ½ hyoid: Derived from pharyngeal arch 3 D. Thyroid carlage: Derived from pharyngeal arch 4 E. Cuniform carlage: Derived from pharyngeal arch 6

Queson #6: Which of the following nerves are derived from pharyngeal arch 4?

A. CN V B. CN VII C. CN IX D. Superior laryngeal E. Recurrent laryngeal Queson #6:

A. CN V: Derived from Pharyngeal arch 1 B. CN VII: Derived from Pharyngeal arch 2 C. CN IX: Derived from pharyngeal arch 3 D. Superior laryngeal: Derived from pharyngeal arch 4 E. Recurrent laryngeal: Derived from pharyngeal arch 6

Queson #7: Which of the following structures are derived from pharyngeal arch 3?

A. Cricothyroid muscle B. Stylopharyngeus muscle C. Stylohyoid muscle D. Cricoid carlage E. Arytenoid carlage Queson #7:

A. Cricothyroid muscle: Derived from pharyngeal arch 4 B. Stylopharyngeus muscle: Derived from pharyngeal arch 3 C. Stylohyoid muscle: Derived from pharyngeal arch 2 D. Cricoid muscle: Derived from pharyngeal arch 6 E. Arytenoid muscle: Derived from pharyngeal arch 6

Queson #8: Which of the following structures are derived from pharyngeal arch 6? A. Palane B. Superior laryngeal nerve C. Most pharynx muscles D. Upper esophageal muscles E. Facial nerve Queson #8:

A. Palane: Derived from pharyngeal arch 1 B. Superior laryngeal nerve: Derived from pharyngeal arch 4 C. Most pharynx muscles: Derived from pharyngeal arch 4 D. Upper esophageal muscles: Derived from pharyngeal arch 6 E. Facial nerve: Derived from pharyngeal arch 2

Queson #9: Which of the following structures are derived from pharyngeal pouch 4?

A. Inferior parathyroid gland B. Superior parathyroid gland C. Thymus D. Epithelial lining of the middle ear E. Epithelial lining of palane tonsil crypts Queson #9:

A. Inferior parathyroid gland: Derived from pharyngeal pouch 3 B. Superior parathyroid gland: Derived from pharyngeal pouch 4 C. Thymus: Derived from pharyngeal pouch 3 D. Epithelial lining of the middle ear: Derived from pharyngeal pouch 1 E. Epithelial lining of palane tonsil crypts: Derived from pharyngeal pouch 2

Oral and Neck Regions Queson #10: What condion results when the thyroid fails to detach from the foramen cecum?

A. First Arch Syndrome B. Pharyngeal fistula C. DiGeorge Syndrome D. Ectopic thyroid E. Thyroglossal duct cyst Queson #10: A. First Arch Syndrome: First Arch Syndrome results from abnormal development of pharyngeal arch 1 B. Pharyngeal fistula: Pharyngeal fistulas result from the persistence of pharyngeal pouch 2 and pharyngeal groove 2 C. DiGeorge Syndrome: DiGeorge Syndrome results from the failure of pharyngeal pouches 3 & 4 to develop correctly D. Ectopic thyroid: An Ectopic thymus, parathyroid, or thyroid can result from abnormal migraon E. Thyroglossal duct cyst: While the thyroid migrates down the neck during development, it remains aached to the posterior part of tongue (foramen cecum) by the thyroglossal duct. Typically, this connecon atrophies; however, in rare cases it persists and develops into a thyroglossal duct cyst.

Queson #11: Which of the following nerves is responsible for special taste sensaon in the posterior 1/3 of the tongue?

A. Mandibular nerve B. Glossopharyngeal nerve C. Chorda tympani D. Internal laryngeal nerve E. Olfactory nerve Queson #11: A. Mandibular nerve: Provides motor innervaon to the muscles of mascaon B. Glossopharyngeal nerve: The posterior 1/3 of the tongue is innervated by the glossopharyngeal nerve (IX) for both general and special taste sensaons C. Chorda tympani: anterior 2/3 of the tongue is innervated by the trigeminal nerve (V3) for general sensaon and by the facial nerve (VII) via the chorda tympani for special taste sensaon D. Internal laryngeal nerve: The upper part of the larynx & epiglos are innervated by the vagus nerve (X) for general and special taste sensaon, speciﬁcally as internal laryngeal nerve of the superior laryngeal nerve. (See Moore Fig 8.91) E. Olfactory nerve: Responsible for sense of smell

Queson #12: A cle lip can result when which two of the following structures fail to fuse during development? A. Two adjacent maxillary prominences B. Two intermaxillary segments C. Intermaxillary segment and adjacent maxillary prominence D. Primary palate and secondary palate E. Two palane shelves Queson #12:

A. Two adjacent maxillary prominences B. Two intermaxillary segments C. Intermaxillary segment and adjacent maxillary prominence: When the intermaxillary segment fails to fuse with the adjacent maxillary prominence, a cle lip will develop unilaterally or bilaterally D. Primary palate and secondary palate: An anterior cle palate results when the secondary palate fails to fuse with the primary palate E. Two palane shelves: A posterior cle palate results when the two palane shelves fail to unite along the palane raphe

Queson #13: A posterior cle palate can result when which two of the following structures fail to fuse during development? A. Two adjacent maxillary prominences B. Two intermaxillary segments C. Intermaxillary segment and adjacent maxillary prominence D. Primary palate and secondary palate E. Two palane shelves

Queson #13:

Queson #14: A child presents to the clinic with pneumonia. You noce that the child has an underdeveloped chin and small ears; the mother also informs you that this is the fourth case of pneumonia the child has had this year. What other clinical condion would you expect to accompany the ones previously menoned if you suspect DiGeorge Syndrome? A. Hypocalcemia B. Hypercalcemia C. Pharyngeal ﬁstula D. Ectopic thyroid E. Ectopic parathyroid Queson #14:

A. Hypocalcemia: DiGeorge Syndrome results from the failure of pharyngeal pouches 3 & 4 to develop correctly producing a weakened immune system due to thymus insufficiency and hypocalcemia from the lack of parathyroid hormone which normally raises calcium levels. B. Hypercalcemia: DiGeorge Syndrome would have the opposite effect C. Pharyngeal fistula: Pharyngeal fistulas result from the persistence of pharyngeal pouch 2 and pharyngeal groove 2. When this combinaon occurs, a hole will develop in the neck. D. Ectopic thyroid: An Ectopic thyroid can result from abnormal migraon. E. Ectopic parathyroid: An Ectopic parathyroidcan result from abnormal migraon.

Ear Queson #15: What week of embryogenesis does the inner ear develop?

A. Week 1 B. Week 2 C. Week 3 D. Week 4 E. Week 5 Queson #15:

A. Week 1 B. Week 2 C. Week 3 D. Week 4: The inner ear develops in the 4th week of embryogenesis arising from a thickened ectodermal layer known as the oc placode which matures into the oc vesicle E. Week 5

Queson #16: Which of the following germ layers gives rise to the inner ear?

A. Ectoderm B. Mesoderm C. Endoderm D. Paraxial mesoderm E. Lateral plate mesoderm Queson #16:

A. Ectoderm: The inner ear develops in the 4th week of embryogenesis arising from a thickened ectodermal layer known as the oc placode which matures into the oc vesicle B. Mesoderm C. Endoderm D. Paraxial mesoderm E. Lateral plate mesoderm

Queson #17: Which of the following embryonic structures do the semicircular ducts/canals derive from?

A. Cochlear duct B. Saccule C. Utricle D. External auditory meatus E. Auricle Queson #17:

A. Cochlear duct B. Saccule: the saccule will develop into the cochlea (hearing) and the saccule “proper” C. Utricle: The utricle develops into the semicircular ducts (equilibrium) and the utricle “proper” D. External auditory meatus E. Auricle

Queson #18: Which of the following structures are joined by the auditory tube?

A. Inner ear and nasopharynx B. Middle ear and nasopharynx C. External ear and nasopharynx D. Inner ear and pharynx E. Middle ear and pharynx Queson #18:

A. Inner ear and nasopharynx B. Middle ear and nasopharynx: The opening to the auditory tube provides a connecon between the middle ear and the nasopharynx C. External ear and nasopharynx D. Inner ear and pharynx E. Middle ear and pharynx

Queson #19: Which of the following structures in the ear is connected to the stapes?

A. Malleus B. Tensor tympani C. Tympanic membrane D. Round window E. Oval window Queson #19:

A. Malleus: Connected to the tympanic membrane, tensor tympani, and incus B. Tensor tympani: Connected to the malleus C. Tympanic membrane: Connected to the malleus D. Round window: Connected to secondary tympanic membrane E. Oval window: The stapes is connected to the oval window of the inner ear and transmits mechanical sound into liquid vibraons

Eye Queson #20: The rena develops from neuroectoderm in a speciﬁc chronology of events. Which of the following displays the correct order of events from beginning to end?

A. Opc vesicle à opc sulcus à opc cup B. Opc sulcus à opc vesicle à opc cup C. Opc vesicle à opc sulcus à opc stalk D. Opc sulcus à opc vesicle à opc stalk E. Opc vesicle à opc stalk à opc cup Queson #20:

A. Opc vesicle à opc sulcus à opc cup B. Opc sulcus à opc vesicle à opc cup: The rena develops from neuroectoderm in a chronology of events as follows: opc sulcus, opc vesicle, opc cup C. Opc vesicle à opc sulcus à opc stalk D. Opc sulcus à opc vesicle à opc stalk E. Opc vesicle à opc stalk à opc cup

Queson #21: Which of the following structures mature into the central artery and vein of the rena?

A. Hyaloid Vessels B. Opc stalk C. Opc cup D. Choroid ﬁssure E. Choroidal layer Queson #21:

A. Hyaloid vessels: When the choroid fissure closes, the hyaloid vessels mature into the central artery and vein of the rena B. Opc stalk: The opc stalk becomes the opc nerve (CN II) C. Opc cup: The opc cup forms the rena and part of the iris D. Choroid fissure: The opc stalk has a choroid fissure inferiorly with the hyaloid vessels E. Choroidal layer: From anterior to posterior, the iris is composed of the choroidal layer, outer pigment layer of rena, and the inner neural layer of rena

Queson #22: The cornea arises from which embryonic structure?

A. Surface ectoderm B. Neural crest mesenchyme C. Mesoderm D. A and B E. B and C Queson #22:

A. Surface ectoderm: The lens placode is derived from surface ectoderm B. Neural crest mesenchyme: The ciliary muscles are formed from overlying neural crest mesenchyme C. Mesoderm: The extraocular muscles and the vessels associated with the eye arise from mesoderm D. A and B: The cornea arises from surface ectoderm and neural crest mesenchyme E. B and C

Queson #23: From anterior to posterior, the iris is composed of which layers? A. Outer layer of the rena à ciliary body à inner neural layer of the rena B. Ciliary body à outer layer of the rena à inner neural layer of the rena C. Choroidal layer à outer pigment layer of rena à inner neural layer of the rena D. Outer pigment layer of rena à choroidal layer à inner neural layer of the rena Queson #23:

A. Outer layer of the rena à ciliary body à inner neural layer of the rena B. Ciliary body à outer layer of the rena à inner neural layer of the rena C. Choroidal layer à outer pigment layer of rena à inner neural layer of the rena: From anterior to posterior, the iris is composed of the choroidal layer, outer pigment layer of rena, and the inner neural layer of rena D. Outer pigment layer of rena à choroidal layer à inner neural layer of the rena

Queson #24: Which of the following structures of the eye are derived from neural crest cells?

A. Lens placode B. Cornea C. Ciliary body D. Extraocular vessels E. Choroid layers Queson #24:

A. Lens placode: The lens placode is derived from surface ectoderm B. Cornea: The cornea arises from surface ectoderm and neural crest mesenchyme C. Ciliary body: The ciliary body of the iris derives from the outer & inner renal layers D. Extraocular vessels: The extraocular muscles and the vessels associated with the eye arise from mesoderm E. Choroid layers: The sclera and choroid layers of the eye develop from neural crest cells

Queson #25: Coloboma Iridis results when what structure(s) fails to close?

A. Ciliary processes B. Choroid ﬁssure C. Choroid layers D. Sclera E. Rena Queson #25:

A. Ciliary processes: The ciliary processes produce aqueous humor that circulates from the posterior chamber (between lens and iris) through the pupil and into the anterior chamber of the eye (between the iris and cornea) B. Choroid fissure: Coloboma Iridis results when the choroid fissure fails to close. Although the “notch” may appear in other areas, the most common place is the iris C. Choroid layers: The choroid layer nourishes the outer layers of the rena D. Sclera: Tough fibrous ssue that protects and maintains shape of the eye E. Rena: Focuses light into neural signals