Ten Cate's Development, structure and function

Question 1

Continuous thickened band of epithelium forms around mouth in presumptive upper and lower jaws after how long?

Answer 1

37 days of development

Question 2

Thickened bands of epithelium are shaped like?

Answer 2

Horse-shoe shaped

Question 3

Why are thickened bands of epithelium horse-shoe shaped?

Answer 3

They correspond in position to the future dental arches of the upper and lower jaws

Question 4

Formation of these thickened epithelium horse-shoe bands are a result of?

Answer 4

• Change in orientation of the mitotic spindle and cleavage plane of dividing cells

Question 5

Primary epithelial band quickly gives rise to?

Answer 5

Two subdivisions which ingrow into the underlying mesenchyme colonized by neural crest cells

Question 6

Which lamina forms first from primary epithelial band?

Answer 6

Dental lamina forms first. Vestibular lamina forms second.

Question 7

Vestibular lamina is positioned in front or behind dental lamina?

Answer 7

Just in front of dental lamina

Question 8

What is a key feature of initiation of tooth development?

Answer 8

Formation of localized thickenings or placodes within the primary epithelial bands.

Question 9

Role of dental placodes?

Answer 9

Believed to initiate formation of the various tooth families

Question 10

Morphology of dental placodes?

Answer 10

Morphologically similar to those of teeth, also initiate the development of other ectodermal appendages, such as hair and feathers

Question 11

Formation and growth of dental placodes is believed to involve?

Answer 11

• Transcription factor p63
• TNF
• Ectodysplasin (Eda)
• Others

Question 12

Overactivation of ectodysplasin leads to?

Answer 12

Extra teeth with aberrant morphology

Question 13

Smaller than normal dental placodes leads to?

Answer 13

Missing and smaller teeth

Question 14

Larger dental placodes leads to?

Answer 14

Supernumerary and larger teeth

Question 15

Vestibule forms as a result of?

Answer 15

As a result of proliferation of the vestibular lamina into the ectomesenchyme soon after the formation of dental lamina

Question 16

Cells of the vestibular lamina rapidly enlarge and then?

Answer 16

Degenerates to form a cleft that becomes the vestibule between the cheek and the tooth-bearing area.