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Flashcards in EXAM III Final Deck (106)
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31

Which of the following during cornea development induces overlying ectoderm to transform from bilayered epithelium (simple cuboidal basal layer plus flattened periderm) to transparent multi-layered cornea?

a. Lens placode
b. Lens ectoderm
c. Neural crest
d. Lens vesicle
e. Neural plate

Lens vesicle

32

During the development of the retina, Shh stimulates which of the following to differentiate into the pigmented retina, which is the outer layer of the optic cup?

a. Otx2
b. BMP-4
c. Tbx-5
d. Vax-2
e. Eph

Otx2

Inner layer of the optic cup is the sensory layer

33

Retinal polarity is fixed into a nasotemporal (anterior-posterior) and dorsoventral axis. Which of the following is associated with the establishment of the nasotemporal axis?

a. Shh, BMP, and Ventroptin
b. Shh and Otx2
c. Foxe3
d. Ephrins and receptors

Ephrins and receptors - nasotemporal axis is fixed first while dorsoventral is fixed second

34

Retinal polarity is fixed into a nasotemporal (anterior-posterior) and dorsoventral axis. Which of the following is associated with the establishment of the dorsoventral axis?

a. Shh, BMP, and Ventroptin
b. Shh and Otx2
c. Foxe3
d. Ephrins and receptors

Shh, BMP, and Ventroptin - nasotemporal axis is fixed first while dorsoventral is fixed second

35

Which of the following is known as an absence of an eye resulting from a mutation in RAX, is very rare and can normally be attributed to lack of formation of the optic vesicle?

a. Anophthalmos
b. Microphthalamos
c. Coloboma
d. Congenital cataract
e. Cyclopia

Anophthalmos

36

Which of the following congenital malformation of the eye can range from an eyeball that is slightly smaller than normal to one that is almost vestigial.

a. Anophthalmos
b. Microphthalamos
c. Coloboma
d. Congenital cataract
e. Cyclopia

Microphthalamos

37

Which of the following congenital malformations of the eye is due to nonclosure of the choroid fissure of the iris during the 6-7th week? Individuals are sometimes sensitive to bright light.

a. Anophthalmos
b. Microphthalamos
c. Coloboma
d. Congenital cataract
e. Cyclopia

Coloboma

38

Which of the following is an evagination from the roof of the stomodeal ectoderm and is the primordium for the anterior pituitary/adenohypophysis?

a. Thyroid
b. Trachea
c. Rathke's pouch
d. Reichert's cartilage
e. Meckel's cartilage

Rathke's pouch

39

A lack of which signaling molecule causes the first pharyngeal arch to develop into jaws?

a. BMP
b. Shh
c. Hox
d. Wnt

Hox

40

Which of the following is necessary to keep pharyngeal arch 2 from differentiating into arch 1 and forming the jaws?

a. BMP
b. Shh
c. Hoxa-2
d. Wnt

Hoxa-2

41

During craniofacial development, which of the following signaling molecules allows for the segmentation of cranial neural tube, which becomes carried over onto neural crest cells that give rise to neural crest tissue?

a. Wnt
b. BMP
c. Shh
d. Hox

Hox

42

Which of the following molecules induces the formation of the frontonasal ectodermal zone?

a. Shh
b. Hox
c. Wnt
d. BMP

Shh from the forebrain = dorsoventral gradient

Dorso = FGF-8
Ventral = Shh

43

For jaw primordia, neural crest are derived from which centers of the brain for the maxillary and mandibular processes?

Maxillary = forebrain and midbrain

Mandibular = hindbrain and midbrain

44

What are the two process of the primordia of the palate?

Median palatine process = unpaired = premaxilla

Lateral palatine processes = paired = secondary plate

45

Which of the following is a condensation of mesenchymal cells around the developing tooth which will form the cementum and periodontal ligament = jaw attachment?

a. Tooth bud
b. Enamel organ
c. Dental lamina
d. Dental sac

Dental sac

46

Which of the following is necessary for tooth development to continue past the bud stage?

a. BMP-4
b. Shh
c. FGF-8
d. Pax-9
e. Msx-1, Msx-2

Pax-9

47

Which of the following causes the formation of the future cusps of the molar?

a. Primary enamel knot
b. Secondary enamel knot
c. Pax-9
d. Hox

Secondary enamel knot

48

Which of the following molecules is branching pattern of salivary glands highly dependent upon?

a. Shh
b. Hox
c. FGF
d. Wnt

Shh

49

For salivary gland development, where does the signaling between Shh and FGF occur? One major difference compared to other types of glandular development.

a. Between the epithelium and mesenchyme
b. Within the epithelium
c. Outside of the epithelium
d. Within the endoderm

Within the epithelium

50

Which of the following results from the lack of fusion of the maxillary and nasomedial process?

a. Cleft lip
b. Cleft palate
c. Holoprosencephaly
d. Dentinogenesis imperfecta
e. Amelogenesis imperfecta

Cleft lip

51

Which of the following defects is based on the defective formation of the forebrain and include external facial malformations, with an extreme case of nose reduction defects, cyclopia (near absence of upper facial & midfacial tissue)

a. Cleft lip
b. Cleft palate
c. Holoprosencephaly
d. Dentinogenesis imperfecta
e. Amelogenesis imperfecta

Holoprosencephaly

52

Which of the following is the main organizer for pharyngeal arch development?

a. Foregut endoderm
b. Midgut endoderm
c. Hindgut endoderm
d. Hindgut mesoderm

Foregut endoderm

53

What two molecules are important in the formation of pharyngeal arches?

a. Hox and Shh
b. Pax and Wnt
c. Tbx1 and FGF8
d. FGF8 and Wnt
e. Shh and Tbx1

Tbx1 and FGF8

54

What molecules cause the formation of the inferior parathyroids and the thymus?

Inferior parathyroid = Shh (pouch 3)

Thymus = BMP-4 (pouch 3)

55

Which of the following becomes incorporated into thyroid as parafollicular (C) cells which secrete calcitonin?

a. Inferior parathyroid
b. Superior parathyroid
c. Postbranchial/ultimobranchial body
d. Thymus

Postbranchial/ultimobranchial body = 4th pouch

56

What is the location of the thyroid in relation to the pharyngeal arches?

Between 1st and 2nd arches

Grows down into underlying mesenchyme as thyroid diverticulum and remains connected temporarily to the floor of the pharynx via thyroglossal duct

Opening of duct = foramen cecum (small pit at base of tongue)

57

What are some characteristics of the pronephros?

Among the first kidneys to develop
Non-functional solid cords required for the remainder of the excretory system to develop

58

The induction of the pronephric ducts requires many molecules, what is the primary inducer and what molecules determine the craniocaudal limits of early urinary system?

a. RA, Hox 4-11
b. RA, Pax 3 and 7
c. Shh, Hox 4-11
d. Shh, Pax 3 and 7

RA and Hox 4-11

59

During the induction of the pronephric ducts, which molecule causes the aggregation of mesenchymal cells in the intermediate mesoderm into pronephric ducts by way of Pax-2 and Pax-8?

a. RA
b. Hox 4-11
c. Lim-1
d. Foxe3
e. Wt-1

Lim-1; formed by TFs Pax-2,8 via Hox 4-11

60

Which of the following is the functional kidney in most vertebrate embryos?

a. Pronephros
b. Mesonephros
c. Metanephros
d. Renal tubules

Mesonephros; caudal to the pronephros containing mesonephric tubules