Bilateral nasal placodes appear during:

 # During which week of development do the bilateral nasal placodes appear?

a. Fourth.

b. Fifth.

c. Sixth.

d. Seventh.

The correct answer is b. Fifth.

During the fifth week, the bilateral nasal placodes, or thickened areas of epithelium,

appear in the upper border of the lip.

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Palatal shelf elevation takes place during:

 # Palatal shelf elevation takes place during which prenatal week of development? 

a. Week 7. 

b. Week 8. 

c. Week 9. 

d. Week 10

The correct answer is: B. Week 8.

Palatal shelf elevation occurs during the eighth prenatal week.

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Zone of fusion between the medial nasal and maxillary process

 # The zone of fusion between the medial nasal and maxillary process is referred to as which of the following? 

a. Cleft lip. 

b. Philtrum. 

c. Nasal fin. 

d. Maxillonasal process.

The correct answer is C. Nasal fin.

A lack of contact or fusion of the medial nasal and maxillary processes results in either a unilateral or bilateral cleft lip. The medial nasal process is called the philtrum. The epithelial coverings of the medial nasal and maxillary processes normally contact and create a zone of fusion termed the nasal fin. 

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Meckel's cartilage is replaced by:

 # Which of the following replace Meckel’s cartilage? 

a. The body of the mandible and the cartilaginous condyle. 

b. The body of the mandible and the condylar unit. 

c. The condylar unit and the angular process. 

d. The alveolar process and the cartilaginous condyle.

The correct answer is: A. The body of the mandible and the cartilaginous condyle.

Together, the body of the mandible and the cartilaginous condyle replace Meckel’s cartilage. The body of the mandible and the condylar unit do not replace Meckel’s cartilage. The condylar unit and the angular process do not replace Meckel’s cartilage. The alveolar process and the cartilaginous condyle do not replace Meckel’s cartilage.

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Face and brain are first supplied by:

 # The face and brain are first supplied by which of the following arteries? 

a. Internal carotid artery. 

b. External carotid artery. 

c. Common carotid artery. 

d. Stapedial artery.

The correct answer is A. Internal carotid artery.

The face and brain are first supplied by the internal carotid artery. The facial vessels form at 7 weeks and then detach from the internal carotid artery and attach to the external carotid artery. The face and brain are first supplied by the internal carotid artery, not by the common carotid artery. The face and brain are first supplied by the internal carotid artery, not by the stapedial artery.

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# Which cranial nerve is tested by hoarseness and muscle response after saying “Ah”?

 # Which cranial nerve is tested by hoarseness and muscle response after saying “Ah”? 

a. Glossopharyngeal. 

b. Trigeminal. 

c. Vagus. 

d. Hypoglossal.

The correct answer is C. Vagus.

Testing the glossopharyngeal nerve includes placing a sweet or salty substance on the posterior one third of tongue. To test the trigeminal nerve, the patient is asked to bite down and to touch his/her face. Muscles responses after saying “Ah” hoarseness are test for the vagus nerve. Tongue protrusion is used to test the hypoglossal nerve.

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Primary function of the optic nerve

 # The primary function of the optic nerve is which of the following? 

a. Lateral rectus muscle and eyeball. 

b. Superior oblique muscle and eyeball. 

c. Eyelid and some eyeball. 

d. Vision.

The correct answer is D. Vision.

The abducens nerve acts on the lateral rectus muscle and eyeball. The trochlear nerve acts on the superior oblique muscle and eyeball. The oculomotor nerve acts on the eyelid and some eyeball. The primary function of the optic nerve is vision.

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