Embryology

Question 1

What impedes the movement of sperm?

Answer 1

Female antibodies
Cervix
Uterotubal junction

Question 2

Where does fertilisation usually occur?

Answer 2

In the ampulla (wider middle) of the uterine tube

Question 3

What is the maternal egg surrounded by?

Answer 3

Outer corona radiata
Tough covering zona pellucida
Oocyte cell membrane

Question 4

What happens at the first cell division?

Answer 4

Male and female chromosomes condense and divide by mitosis.

It is still contained in the zone pellucida

Question 5

What is the bundle of cells the stage after the zygote called?

Answer 5

Morula

Question 6

What is the name of the inner cells of the morula?

Answer 6

Embryoblast - will become the embryo

Question 7

What is the name of the outer cells of the morula?

Answer 7

Trophoblast - will become the placenta

Question 8

What is a blastocyst?

Answer 8

When the inner cells of the morula move to one end and leave a fluid filled cavity

Question 9

What happens during implantation?

Answer 9

Blastocyst attaches to the uterine wall.

If more than one they spread evenly along the horns

Question 10

What are the two layers of the embryoblast?

Answer 10

Epiblast

Hypoblast

Question 11

What does the epiblast form?

Answer 11

The amniotic cavity

Question 12

What does the hypoblast form?

Answer 12

The yolk sac - the first bit of nutrition before the placenta forms

Question 13

What is the trilaminar germ disc?

Answer 13

Ectoderm
Mesoderm
Endoderm

Question 14

What is the slit at the caudal end of the disc called?

Answer 14

Primitive streak

Question 15

What occurs at the primitive streak?

Answer 15

The epiblast cells migrate through the streak to form the trilaminar layers

Question 16

What is the ectoderm?

Answer 16

The cells that remains in the epiblast on the outside

Question 17

What is the mesoderm?

Answer 17

The cells that migrate through the primitive streak and lie in the middle

Question 18

What is the endoderm?

Answer 18

The cells that migrate through the primitive streak and displace the hypoblasts

Question 19

What does the ectoderm form in the body?

Answer 19

The CNS and the PNS

The epidermis of the skin

Question 20

What does the mesoderm form in the body?

Answer 20

The connective tissues

most stuff

Question 21

?What does the endoderm form?

Answer 21

The gastrointestinal tract - organs and epithelium

The respiratory tract epithelium

Question 22

What are the 3 parts of the mesoderm?

Answer 22

Paraxial mesoderm
Intermediate mesoderm
Lateral plate mesoderm

Question 23

What does the paraxial mesoderm form?

Answer 23

The somites

Question 24

What does the intermediate mesoderm form?

Answer 24

The urogenital systems

Question 25

What does the lateral plate mesoderm form?

Answer 25

Visceral - muscular gut wall

Parietal - body wall

Question 26

What is it called when all the organs are the wrong way round?

Answer 26

Situs invertus

Question 27

What is the notochord?

Answer 27

The midline, skeletal rod in embryos

Question 28

What does the notochord induce?

Answer 28

Proliferation(growth) of the paraxial mesoderm

Development of the neural folds to form the neural groove

Question 29

What does the neural tube form?

Answer 29

The CNS

Question 30

hat do the neural crest cells form?

Answer 30

The PNS

Question 31

What is head to tail folding called?

Answer 31

Cephalocaudal folding

Question 32

What is folding round the body called?

Answer 32

Lateral folding

Question 33

What are non identical twins called?

Answer 33

Dizygotic

Question 34

What are identical twins called?

Answer 34

Monozygotic