Embryology 1

Question 1

name of cell division process in spermatogenesis/oogenesis?

Answer 1

meiosis
2 step process
produces haploid gametes

Question 2

what is produced through oogenesis?

Answer 2

1 ovum and 3 polar bodies (follicles formed at same time as egg but they cannot be fertilised)

Question 3

what is produced through spermatogenesis?

Answer 3

4 sperms

Question 4

define zygote

Answer 4

a diploid sex cell- it is the first cell of a human being

genetically unique as it has 23 c from mum and dad

Question 5

what does a zygote divide to form in pre embryonic phase?

Answer 5

blastocyst

Question 6

where do the mitochondria and organelles come from?

Answer 6

the mum as the sperm leaves them all behind and only the pro-nucleus of the sperm fuses with the egg at fertilisation

Question 7

what is a morula?

Answer 7

a solid ball of cells formed when a zygote divides a number of times
zygote- morula- blastocyst

Question 8

blastocyst structure

Answer 8

trophoblast
inner cell mass
blastocyst cavity

Question 9

what is a trophoblast

Answer 9

the outer lining of cells of the blastocyst

Question 10

what is inner cell mass

Answer 10

accumulation of cells at one end of blastocyst that forms the baby

Question 11

how does the fertilised egg move down uterine tube?

Answer 11

cilia beat egg down, mucous secretion helps reduce friction

Question 12

ectopic pregnancy

Answer 12

if it occurs anywhere outwith uterine cavity

could occur if cilia function is abnormal

Question 13

when is the pre-embryonic phase

Answer 13

0-3 weeks

Question 14

when is the embryonic phase

Answer 14

4-8 weeks

Question 15

when is the foetal phase

Answer 15

9-40 weeks

Question 16

fertilisation

Answer 16

pronucleus of sperm enters pronucleus of ovum to give a diploid zygote

Question 17

define pronucleus

Answer 17

pronucleus is either of a pair of gametic nuclei, in the stage following meiosis but before their fusion leads to the formation of the nucleus of the zygote.

Question 18

pre-embyronic phase: week 1

Answer 18

zygote is formed and it then divides to form a blastocyst

it moves through uterine tube, to reach uterine cavity

Question 19

which is the first cell in the body

Answer 19

zygote

it is diploid- 46 chromosomes

Question 20

how does a zygote divide

Answer 20

by mitosis forming 2 then 4 then 8

Question 21

what is a solid ball of cells called that is formed from zygote division

Answer 21

morula

Question 22

what goes on to form the baby from the blastocyst

Answer 22

the inner cell mass

Question 23

what is the lining of the blastocyst called

Answer 23

trophoblast

Question 24

what is the lining/ wall of the uterus called

Answer 24

endometrium- smooth muscle where embryo wants to be embedded

Question 25

how does the egg move down the Fallopian tube?

Answer 25

cilia on epithelium beating it through

Question 26

what is an ectopic pregnancy

Answer 26

egg implanting in uterine tube itself may be due to cilia function is abnormal

Question 27

week 2 of pre-embryonic phase

Answer 27

implantation occurs and placenta begins to develop

cells that later form the embryo form a bilaminar disc

sacs, membranes and cord to nourish the human conceptus (baby) start to form

Question 28

does the ovum divide as it moves through fallopian tube

Answer 28

yes it does and it becomes a blastocyst just as it reaches the uterine cavity normally

Question 29

where does implantation occur

Answer 29

in the endometrium- lining of the uterus

Question 30

what does the chorion do

Answer 30

Implantation process (chorionic villi)

Forms part of the placenta in due course

Secretes human Chorionic gonadotropin (HCG)

Question 31

what does a trophoblast form

Answer 31

a chorion

Question 32

what can HCG hormone be used to detect in women

Answer 32

pregnancy, hormone can be detected in urine

Question 33

what does the chorion have on it’s surface and why is this helpful

Answer 33

it has chorional villi that enable it to penetrate into the endometrium and implant into the uterine cavity lining.

Question 34

what is the endometrium called after implantation

Answer 34

decidua

Question 35

what do the cells of the inner cell mass form

Answer 35

a 2- layered flat disc called the bilaminar disc

Question 36

what 2 cavities form either side of the bilaminar disc

Answer 36

amniotic cavity

yolk sac

Question 37

which cavity is formed on top of the bilaminar disc?

Answer 37

amniotic cavity

Question 38

what are the 2 layers of cells called in the bilaminar disc

Answer 38

epiblast

hypoblast (below the epipblast)

Question 39

where does waste accumulate in the embryo

Answer 39

allantoic sac

Question 40

what is the main source of nutrition for an embryo

Answer 40

placenta but also a little from yolk sac

Question 41

main functions of the placenta

Answer 41

Foetal nutrition
Transport of waste and gases
Immune etc