Embryology

Question 1

Oocyte (ovum, egg)

Answer 1

female germ cell

Question 2

Sperm

Answer 2

Male germ cell

Question 3

Zygote

Answer 3

Diploid cell resulting from union of oocyte and sperm at fertilisation

Question 4

Blastomeres

Answer 4

early embryonic cells

Question 5

Morula

Answer 5

Solid mass of 12-32 blastomeres (from Latin - mulberry)

Question 6

Blastocyte

Answer 6

Stage where morula has entered cavity and blastocystic cavity develops within

Question 7

Gastrula

Answer 7

Stage after trilaminar embryonic disc formation

Question 8

Neurula

Answer 8

Stage after gastrula when neural tube forms

Question 9

Embryo

Answer 9

Developing human during embryonic stage (to end of the 8th week)

Question 10

Fetus

Answer 10

Period from the 9th week to birth

Question 11

Week 1

Answer 11

Fertilisation, formation of the morula and blastocyst

Question 12

Week 2

Answer 12

Implantation of blastocyst and formation of bilaminar embryonic disc and early placenta

Question 13

Week 3

Answer 13

Differentiation of cell layers to form the trilaminar embryonic disc

Question 14

Week 4

Answer 14

Folding of the embryo and continuing development of the 3 germ layers (ectoderm, endoderm and mesoderm)

Question 15

Week 5-8

Answer 15

Development of all external and internal structures (organogenetic period)

Question 16

End of Week 8

Answer 16

Embryo looks like an ‘adult’ and is called the fetus. Growth becomes the predominant feature from this point onwards.

Question 17

What comes from the ectoderm?

Answer 17

Skin, nervous system, neural crest (contributes to cardiac outflow, coronary arteries)

Question 18

What comes from the mesoderm?

Answer 18

All types of muscle, most systems, kidneys, blood, bone

Question 19

What comes from the endoderm?

Answer 19

gastrointestinal tract (liver, pancreas but not smooth muscle), endocrine organs

Question 20

What is gastrulation?

Answer 20

Mass movement and invagination (inward folding) of the blastula to form 3 layers (ectoderm, mesoderm, endoderm)