Intro to Embryology

Question 1

preembryonic phase weeks

Answer 1

0-3 weeks

Question 2

embryonic phase weeks

Answer 2

4-8 weeks

Question 3

foetal phase weeks

Answer 3

9-40 weeks

Question 4

what occurs in week 1 of preembryonic phase

Answer 4

zygote is formed, divides to form blastocyst, moves through uterine tube to reach uterine cavity

Question 5

mitchondrial diseases are inherited from

Answer 5

mother because only eggs contribute mitochondria to the next generation

Question 6

solid ball of cells following mitosis is called

Answer 6

morula

Question 7

why does morula turn into blastocyst

Answer 7

the inner cells of a morula cannot get nutrition so the blastocyst is formed in order to get them the nutrition they need using the trophoblast, inner cell mass and blastocyst cavity structure

Question 8

where does blastocyst formation occur

Answer 8

uterine cavity where it implants into endometrium

Question 9

how does ovum or fertilised ovum move through Fallopian tube

Answer 9

ciliated epithelium beat the ovum to move it to uterine vanity

Question 10

ectopic pregnancy

Answer 10

ovum implants somewhere outside of the uterine cavity due to inflammation in the uterine tube which prevents the function of the ciliated epithelium

Question 11

what occurs in week 2 of preembryonic phase

Answer 11

implantation occurs in uterine endometrial layer and placenta begins to develop, cells that later form the embryo form a bilaminar disc, sacs, membranes and cord to nourish the baby start to form

Question 12

trophoblast divides to form two layers which ultimately forms a

Answer 12

chorion which has finger like projections called chorionic villi

Question 13

functions of chorion

Answer 13

implantation process, forms part of placenta in due course and secretes human chorionic gonadotropin HCG which is used to detect pregnancy

Question 14

endometrium with implanted conceptus

Answer 14

decidua

Question 15

what happens to inner cell mass in week 2

Answer 15

form a 2 layered flat disc called the bilaminar disc so that 2 cavities now begin to form -amniotic cavity and yolk sac

Question 16

functions of placenta

Answer 16

foetal nutrition, transport of waste and gases, immune system

Question 17

what type of twins share placenta

Answer 17

monozygotic, identical. same genetic makeup and one placenta

Question 18

primitive streak

Answer 18

formed in the midline of the epiblast in week 3 by the dipping in of cells and once the primitive streak is formed, the axis of the embryo is formed

Question 19

3 germ layers

Answer 19

ectoderm, mesoderm, endoderm

Question 20

how is trilaminar disc formed and name of the process

Answer 20

epiblast cells migrate to inbetween the epiblast and hypoblast and then displace the hypoblast to form three germ layers and cells are now specialised.

Question 21

name of the process of how trilaminar disc formed

Answer 21

gastrulation

Question 22

what is neural tube formation called

Answer 22

neurulation

Question 23

how is neural tube formed

Answer 23

cells from ectoderm sink down to form a solid tube, release notochord then neural plate is formed in the ectoderm, those neural plates sink down to form neural tube which causes crests to form on surface which eventually join which is induced by the notochord

Question 24

what happens to mesoderm after neurulation

Answer 24

thickens and then separates into three parts

Question 25

three parts of mesoderm

Answer 25

paraxial mesoderm, intermediate plate mesoderm, lateral plate mesoderm (which splits)

Question 26

where are somites formed

Answer 26

paraxial mesoderm

Question 27

somites are split into 3 which are

Answer 27

dermatome, myotome, sclerotome

Question 28

what happens after somites formed and split

Answer 28

lateral folding and the lateral plate mesoderm that split joins with other split at end in C shape

Question 29

endoderm forms what

Answer 29

gut and respiratory system

Question 30

lateral plate mesoderm forms what

Answer 30

peritoneum, pleura, body cavities

Question 31

intermediate plate mesoderm forms what

Answer 31

urogenital system eg kidneys and reproductive

Question 32

ectoderm forms what

Answer 32

epidermis of skin and neural tube

Question 33

paraxial mesoderm forms

Answer 33

dermatome (dermis), myotome (muscles), sclerotome (bones)

Question 34

teratology

Answer 34

study of when things go wrong during development

Question 35

teratogens

Answer 35

environmental factors that cause abnormal development

Question 36

period of greatest sensitivity to teratogens

Answer 36

weeks 3-8

Question 37

period of greatest sensitivity to teratogens

Answer 37

weeks 3-8