Embryology Flashcards Preview

Animal Health Science 1 > Embryology > Flashcards

Flashcards in Embryology Deck (34)
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1
Q

What impedes the movement of sperm?

A

Female antibodies
Cervix
Uterotubal junction

2
Q

Where does fertilisation usually occur?

A

In the ampulla (wider middle) of the uterine tube

3
Q

What is the maternal egg surrounded by?

A

Outer corona radiata
Tough covering zona pellucida
Oocyte cell membrane

4
Q

What happens at the first cell division?

A

Male and female chromosomes condense and divide by mitosis.

It is still contained in the zone pellucida

5
Q

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

A

Morula

6
Q

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

A

Embryoblast - will become the embryo

7
Q

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

A

Trophoblast - will become the placenta

8
Q

What is a blastocyst?

A

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

9
Q

What happens during implantation?

A

Blastocyst attaches to the uterine wall.

If more than one they spread evenly along the horns

10
Q

What are the two layers of the embryoblast?

A

Epiblast

Hypoblast

11
Q

What does the epiblast form?

A

The amniotic cavity

12
Q

What does the hypoblast form?

A

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

13
Q

What is the trilaminar germ disc?

A

Ectoderm
Mesoderm
Endoderm

14
Q

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

A

Primitive streak

15
Q

What occurs at the primitive streak?

A

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

16
Q

What is the ectoderm?

A

The cells that remains in the epiblast on the outside

17
Q

What is the mesoderm?

A

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

18
Q

What is the endoderm?

A

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

19
Q

What does the ectoderm form in the body?

A

The CNS and the PNS

The epidermis of the skin

20
Q

What does the mesoderm form in the body?

A

The connective tissues

most stuff

21
Q

?What does the endoderm form?

A

The gastrointestinal tract - organs and epithelium

The respiratory tract epithelium

22
Q

What are the 3 parts of the mesoderm?

A

Paraxial mesoderm
Intermediate mesoderm
Lateral plate mesoderm

23
Q

What does the paraxial mesoderm form?

A

The somites

24
Q

What does the intermediate mesoderm form?

A

The urogenital systems

25
Q

What does the lateral plate mesoderm form?

A

Visceral - muscular gut wall

Parietal - body wall

26
Q

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

A

Situs invertus

27
Q

What is the notochord?

A

The midline, skeletal rod in embryos

28
Q

What does the notochord induce?

A

Proliferation(growth) of the paraxial mesoderm

Development of the neural folds to form the neural groove

29
Q

What does the neural tube form?

A

The CNS

30
Q

hat do the neural crest cells form?

A

The PNS

31
Q

What is head to tail folding called?

A

Cephalocaudal folding

32
Q

What is folding round the body called?

A

Lateral folding

33
Q

What are non identical twins called?

A

Dizygotic

34
Q

What are identical twins called?

A

Monozygotic