Embryology Flashcards Preview

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Flashcards in Embryology Deck (46):
1

Where is the egg fertilised

Uterus

2

Describe process of egg development

Zygote -> morula -> blastocyst -> blastocoele

3

What comprises the blastocyst

Trophoblast
Inner cell mass

4

What is the trophoblast

Extraembryonic structure --> uterus

5

What is the inner cell mass

Embryonic structure

6

The first division of the inner cell mass leads to two sections called the

Epiblast & hypoblast

7

The hypoblast becomes

Extraembryonic tissue
Extends over the cavity and lines the sides
Becomes the yolk sak

8

The epiblast is the

Embryo

9

The epiblasts consists of

Hollow cavity = primordial amniotic cavity

10

Bilamnar disk

Disk seperating the aminiotic cavity with the yolk sack

11

Where does the primitive streak originate from

The upper surface of the epiblast

12

The primitive streak invaginates to form

The primitive groove

13

The primitive groove gives rise to

Endoderm
Mesoderm
Ectoderm

14

Gastrulation

When the three germ layers form from the primitive groove

15

The endoderm is formed during gastrulation when

The first epiblast cells move to hypo

16

The mesoderm is formed when

2nd epiblast cells into epi and eno

17

The ectoderm is formed during gastrulation when

All the other two layers are formed -> these are just left behind!

18

Describe the formation of the notochord

Cells move from the ectoderm into the mesoderm to form the notocord. Move via the primitive node

19

Describe the notocord

Primitive
Only in embryo
Under spinal cord
First structure to form
Gives animal anterior and posterior

20

Ectoderm will give rise to which structures

Nervous system & epidermis

21

Mesoderm will give rise to which structures

Blood, heart, kidneys, gonads, bones, muscles, connective tissue

22

Endoderm will give rise to

Epithelium of gut and associated tissues

23

Hox genes

Order of genes predict the expression pattern in embryo

24

Mesenchyme

Shape and behaviour of a cell

25

What are the 3 types of mesoderm

Paraxial mesoderm
Intermediate mesoderm
Lateral mesoderm

26

What does paraxial mesoderm give rise to

Derms
Axial skeleton
Axial and limb muscles

27

What does the intermediate mesoderm give rise to

Urogenital tract

28

What does the lateral mesoderm give rise to

Ventrolateral body wall
Heart
Gut wall
Blood vessels
Visceral pleura

29

What are somitomeres

loose masses of paraxial mesoderm derived cells that form along each side of the neural tube

30

How many somitomeres form

20

31

Which pair of somitomeres become independant

The 8th pair

32

What do the somitomeres below the 8th independent pair become?

Somites

33

What do somites form

Sclerotome or dermomyatome

34

What does sclerotome give rise to

Skeleton except the skull

35

What does dermomyatome become

Dermatome or mytotome

36

What does dermatome become

Dermis of the skin

37

What does myotome become

Trunk muscles

38

What are pharangeal arches

Structure that is like the gills

39

What is the origin of the pharangeal arches

Mesoderm

40

The limbs originate from which germ layer

Mesoderm -> controlled by ectoderm

41

Describe the formation of digits

Start off as disks -> apoptosis

42

Apoptosis

Programmed cell death

43

What is a coelom

body cavity or space than runs the length of a vertebrate. It separates the body into an inner tube and an outer tube. The coelom forms when the lateral plate mesoderm splits.

44

Describe morula

16 cell stage
Day 3

45

What is the neural crest? What later structures does it give rise to

The neural crest is the name for the edges of the neural folds that come to be adjacent to, but separate from, the neural tube.

dorsal root ganglia, spinal nerve fibres, and the sympathetic chain ganglia

46

Where is the notochord? What is it replaced by, during development in vertebrates

The notochord is a rod-shaped, mesodermal structure that helps to organise important adjacent components, notably somites and the overlying neural tube. It is the key anatomical feature in chordates, so all vertebrates have a notochord during early development.