Principles of Embryology

Question 1

What is gametogenesis

Answer 1

Germ cell formation
Oogenesis - oocyte (egg)
Spermatogenesis - spermatoza (sperm)

Question 2

Define fertilization

Answer 2

Fusion of the sperm and the oocyte to form the zygote

Question 3

Define cleavage

Answer 3

Period of rapid cell division (no size increase)

formation of morula then blastocyst (day 1-4)

Question 4

Define Gastrulation

Answer 4

Formation of the germ layers - week 3
ectoderm, mesoderm, endoderm
body axes established

Question 5

What is formation of the body plan

Answer 5

Embryonic folding
Tube-within-a-tube
Gut tube within skin/body wall

Question 6

What is organogenesis

Answer 6

Organ/organ systems formation
Basis of these all in place by end of embryonic period
continued during develop during foetal period

Question 7

What happens during the foetal period

Answer 7

Growth and weight gain
Tissues mature and become functional
Overt sexual differentiation
Bone laid down, connections made in CNS

Question 8

What are the 6 primary processes of zygote development

Answer 8

Cell division
Differentiation - specialisation/change in appearance/adoption of new function
Cell attachment - tissue formation
Apoptosis
Induction - ability of one cell type to cause another to differentiate
Cell migration

Question 9

What are the 2 secondary processes of zygote development

Answer 9

Axis formation/polarity - cells need to know where they are in relation to each other & the embryo
Folding/Rotation - entire embryo/structures within

Question 10

What are the controls of development

Answer 10

Genetic - gene expression (tightly regulated in time and space)
Epigenetic - preferential expression of either the maternal or paternal copy of a gene
Environmental