Embryology

Question 1

Terminology of utero development: 0-3 weeks

Answer 1

• conceptus/embryo

Question 2

Terminology of utero development: 3-8 weeks

Answer 2

• embryonic period

Question 3

Terminology of utero development: 9-40 weeks

Answer 3

-fetal period

Question 4

What are the 6 phases of embryogenesis?

Answer 4

• gametogenesis
• fertilisation
• cleavage
• gastrulation
• formation of a body plan
• organogenesis

Question 5

Explain gametogenesis

Answer 5

• formation of gametes

- a gamete is a cell with a complement of 23 chromosomes

Question 6

Process of the formation of male gametes

Answer 6

• spermatogenesis

Question 7

Process of the formation of female gametes

Answer 7

• oogenesis

Question 8

Explain the process of fertilisation

Answer 8

• union of gametes

Question 9

Explain the process of cleavage

Answer 9

• period of rapid cell division

- rapid mitotic cell division with no increase in size

Question 10

Explain the process of gastrulation

Answer 10

• formation of the germ layers

Question 11

What are the names of the 3 layers created during gastrulation?

Answer 11

• ectoderm
• mesoderm
• endoderm

Question 12

What happens during the formation of the body plan?

Answer 12

• embryonic folding

Question 13

Explain the process of organogenesis

Answer 13

• formation of organs and organ systems

Question 14

What occurs during the Foetal period?

Answer 14

• growth and weight gain

Question 15

What does the primary process of induction represent?

Answer 15

• ability of one cell type to cause another to differentiate

Question 16

What does epigenetic mean?

Answer 16

• preferential expression of either the maternal of parental copy of a gene

Question 17

What is fertilisation?

Answer 17

• sperm binds to the glycoprotein –> zona pellucida
• acrosomal enzymes of the sperm breaks its way into the egg
• egg and sperm plasma fuse

Question 18

What does sperm entry into the zona pellicuida trigger?

Answer 18

• triggers the end of meiosis 2 and causes the release of cortical granules by the oocyte

Question 19

Where does fertilisation normally occur?

Answer 19

• the ampulla of the uterine tube

Question 20

What is cleavage?

Answer 20

• the zygote undergoes many mitotic divisions to divide the egg into daughter cells –> blastomere

Question 21

Up to 8 cells in the zona pellicuida, they are all____

Answer 21

• totipotent

Question 22

What is mosaicism?

Answer 22

• individuals with 2 or more cell lines with different chromosome complements

Question 23

Morula is the name given when there are more than __ cells

Answer 23

• 16+ blastomeres

Question 24

What day does implantation normally occur, and where?

Answer 24

• day 6

- posterior or anterior wall of the uterine wall

Question 25

What 2 layers is the bilaminar embryo made up of?

Answer 25

• epiblast

- hypoblast

Question 26

What is an ectopic pregnancy?

Answer 26

• implantation outwit the uterus

Question 27

what week does the primative streak form?

Answer 27

• week 3

Question 28

Explain the process of gasturlation

Answer 28

• movement of epiblast through the primitive streak

- body axis formed

Question 29

hypoblast cells are replaced by what?

Answer 29

• definitive endoderm

Question 30

The epiblast of the bilaminar embryo becomes what in the formation of a triliminar?

Answer 30

• ectoderm

Question 31

What are the 3 layers of the trilaminar disk?

Answer 31

• ectoderm
• mesoderm
• endoderm

Question 32

What does the ectoderm become?

Answer 32

• dermis
• skin
• nails

Question 33

What does the mesoderm become?

Answer 33

• axial skeleton
• organs
• urogential

Question 34

What does the endoderm become?

Answer 34

• lining of the :
• resp tract
• GI tract