Early Human Development

Question 1

what is the firsts step of fertilisation

Answer 1

sperm binds with bona pellucida glycoprotein ZP3

Question 2

what happens after the initial stage of fertilisation

Answer 2

enzymes from sperm
into egg
moms of both fuse
cortisol granule release from egg = fertilisation mem impenetrable by other sperm

Question 3

what is he haploid gamete form

Answer 3

sperm penetrates egg also triggers completion of second meiotic div

Question 4

what is a zygote

Answer 4

fusion of male and female pronuclei restores the diploid num of chromos

Question 5

what surrounds zygote

Answer 5

zona pallucida

Question 6

what ar blastomeres

Answer 6

smaller daughter cells - mitotic div of zygote

Question 7

up to 8 cell stage what is said for the blastomeres

Answer 7

totipotent

Question 8

what is totipotent

Answer 8

give rise to any cell in embryo and supporting tissues

Question 9

when does a blastocyst form

Answer 9

4-5 days

Question 10

so what does a zygote consist of

Answer 10

blastomeres

Question 11

what is a morula

Answer 11

16 blastomeres

Question 12

what happens to a morula

Answer 12

under goes compaction to form a blastocyst

Question 13

what is compaction

Answer 13

forms blastocyst

formation of cell junctions smoothing outside

Question 14

what is blastocyst hatching

Answer 14

zona pellucide breaks

blastocyst free float

Question 15

what does the inner cell mass do

Answer 15

gives rise to embryo

r

Question 16

what do the remaining cells do that are not forming embryo

Answer 16

form the trophoblast which contributes to placenta

Question 17

what are the embryonic stem cells derived from

Answer 17

from ICM

Question 18

what happens after blastocyst hatching

Answer 18

from zona pellucida

embryo interacts directly with endometrial lining of uterus

Question 19

where are normal sites for implantation

Answer 19

middle or upper dorsal uterine wall

Question 20

were are abnormal sites of implantation

Answer 20

ovary
ampulla
uterine tube
lower uterus
cervix
peritoneum

Question 21

what is an ectopic pregnancy

Answer 21

when implantation in abnormal site

Question 22

what kind of process is implantation

Answer 22

active

Question 23

what does the blastocyst interact with or implantation

Answer 23

maternal tissues

Question 24

what happens in implantations at cellular level

Answer 24

trophoblasts divide and secrete subs break endometrial cell connections
cell processes to burrow into uterine walll

Question 25

what happens after implantation

Answer 25

embryo blast | prod cells = cav = amniotic cav/mem

Question 26

when does impacted embryo occur

Answer 26

9-12 days

Question 27

what is a syncytiotrophoblast

Answer 27

placental villi, which invades the wall of the uterus, contacts maternal blood supply

Question 28

where is the amniotic cavity presented

Answer 28

above bilayered embryonic disc and yolk sac below

Question 29

what encircles entire embryo

Answer 29

chorionic cavity

Question 30

what s the earliest indication of placenta

Answer 30

filled maternal blood sinusoids in trophoblasts has connections

Question 31

what is gastrulation

Answer 31

most imp if doesn't occur no further dev | formation of germ layers

Question 32

what happens in gastrulation

Answer 32

2 layers become 3

Question 33

what do cells migrate to in gastrulation

Answer 33

primitive streak

Question 34

what do the additional cells do when they get to primitive streak

Answer 34

go inside and push apart bilaminar structure and form an additional middle layer

Question 35

what are the 3 layers formed from gastrulation

Answer 35

endoderm mesoderm ectoderm

Question 36

what is the endoderm

Answer 36

innermost layer | later form lining of gut

Question 37

what is the mesoderm

Answer 37

middle layer new rise to muscle, bone and internal organs

Question 38

what is the ectoderm

Answer 38

outermost layer | rise to nervous system and skin

Question 39

what is neuralation

Answer 39

formation of neural tube

Question 40

what is the first step of neuralation

Answer 40

an area of the ectoderm is induced to form neural tissue

Question 41

what is the distinctive shape of neural tube

Answer 41

cranial end broader and caudal narower

Question 42

at day 19/20 what happens to neural tue

Answer 42

neural tissue roll up itself and isnkinto body wall of embryo for protection

Question 43

what happens to neural tube formation at day 23

Answer 43

has ant neuropore and post neuropore | cranial closes first

Question 44

what does the neural crest do

Answer 44

undergo epithelial to mesenchymal transition and leave the neuroectodermtm enter the mesoderm

Question 45

what are neural crest derivatives

Answer 45

``` scan cells and meninges DRG autonomic gang bones and CT of craniofacial melanocytes chromatin cells odontoblasts ```

Question 46

how is a 3D embryo formed

Answer 46

cranial, caudal and lateral folding

Question 47

what do pharyngeal arches do

Answer 47

develop in all vertebrates | contribute to much of face and neck

Question 48

when do the diff arches form

Answer 48

1 = day 22 2 + 3 = day 24 4 + 6 = day 29

Question 49

what does each arch consist of

Answer 49

core of mesenchyme - musculature of face and neck neural crest cells - skeletal components of face cranial nerve component artery

Question 50

what sp comes form arch 1

Answer 50

maxilla mandible zygomatic and temporal squamous bones muscles of mast

Question 51

what sp comes form arch 2

Answer 51

muscle facial exp

Question 52

what forms upper and mid facial features

Answer 52

proliferating mesenchyme ventral to developing brain

Question 53

what are the facial swellings

Answer 53

frontonasal prominence nasal placode maxillary prominence mandibular prominence

Question 54

what are the nasal swellings

Answer 54

``` frontonasal prom medial nasal swell lateral nasal swell max prom mand prom ```