Lecture 5

Question 1

2 cell layers formed from mammalian blastocyst

Answer 1

Epiblast- primitive ectoderm

Hypoblast- primitive endoderm

Question 2

Blastodisc consists of

Answer 2

Upper epiblast

Lower hypoblast

Question 3

Blastocoel

Answer 3

Fluid filled space between epiblast and hypoblast

Question 4

Involution

Answer 4

Inward movement through the dorsal lip

Question 5

Convergent extension

Answer 5

Cells elongate in the direction of movement and intercalate

Question 6

Epiboly

Answer 6

Ectoderm also cells flatten and move toward the site of involution

Question 7

Muscles and bones derive from

Answer 7

Somites (blocks of paraxial mesoderm)

Question 8

Sclerotome

Answer 8

Cartilages and bones of vertebral column and ribs

Question 9

Dermonyotome

Answer 9

Dermis and skeletal muscles of the body and limbs

• Myotome: epaxial (deep back muscles) and hypoxia (body wall and limb muscles)
• dermatome: skin dermis

Question 10

One vertebra is made up of?

Answer 10

Posterior half of one somite and anterior half of next somite

Question 11

Specification of spinal segment (vertebra)

Answer 11

Combination of functionally active HOX genes

Adjacent groups have overlapping fun

Question 12

Orthologs

Answer 12

Genes in different species evolved form common ancestral gene

Question 13

Parasols

Answer 13

Gene copies from duplication event within same genome

Question 14

Homeotic Gene

Answer 14

Mutations cause transformation of one organ type into another (homeotic)

Question 15

Stages of Limb/Wing Development

Answer 15

Initiation
Outgrowth (proximal-distal)
Patterning(A-P & D-V)
Chondrogenesis and Ossification (formation cartilages and bones)

Question 16

Process of programmed cell death

Answer 16

Decision to die, execution of death, engulfment of corpse, degradation

Question 17

Uses of cell death

Answer 17

Formation of fingers and toes
Menstruation
Elimination of surplus neuron