mnsr 43

Question 1

first step of fertilisation:
-entry of — into the – which lasts —
the sperm tail is still — outside the – and the head is in the —
- the fusion of the head w/ oocyte is accomplished by — on the egg membrane enveloping the sperm head
- once the 2 membrane fuse there is a immediate —– by the speromotaozn
- newly fertilised oocyte is called – and faces 2 problems:

Answer 1

• sperotozoan into the cumulus mass to fusion which lasts 10-20 min
• zona pellicuda , pervetellian spaces
• microvilli
• immediate cessation of movement
• zygot and the problems are: it must prevent the entry of spermatozoa causing polyspermy and the ovum zygote must complete the 2nd meiotic division

Question 2

polyspermy is prevented by —

Answer 2

cortical reaction

Question 3

in the cortical reaction:
1- on fusion the calcium ions stored in the ER are related into the —
2- this causes series of — of electrical charges being set up in the vitelline membrane which lasts for hours
3- hyperpolization is caused by — membrane permeability to k+ ions and it prevents the fusion with other sperm
4- this events take — of fertilisation so its called fast block to polyspermy
5- cortical granule will fuse with — releasing the content into perivetlline spaces
6- the granules contain – which act on — and prevents the entry of the sperm
7- this event is rapid and takes minutes - slow block to polyspermy

Answer 3

• ooplasm
• hyperpolirizing
• increased
• seconds
• oocyte
• enzyme
• zona pellucida

Question 4

the fusion of male and females gametes are called —
an — commences in the egg involving the metabolic changes including a burst of protein synthesis
within 2 to 3 hours —- will be reactivated and the — polar body is included
actin contains the — seem important in the incorporation of the sperm nucleas at the site of fertilisation
when the sperm enters the – the nucleas envelope disperses immediately

Answer 4

syngamy
activation programme
mioetic divison
second
microfilaments
ooplasm

Question 5

morulla is propelled down the — buy the ciliated epithelium and after ovulation it enter —
the merula becomes —

Answer 5

• fallopian tube
• uterus
• blastocysts

Question 6

type of cells in the blastocyes :

Answer 6

trophoblast and embroblast

Question 7

— are cells in the blastocytes and they are surrounded by inner fluid filled city the balstocelic cavity and this fluid accumulation is possible bc of the tight junctions between the cells

Answer 7

outer layer of tripohecoderm ( trophoblast ) and they are the first extra embryonic tissue , sac surrounds the foetus ab metal proton of the placenta for a site of exchange of nutrients

Question 8

– are cells of the blastocysts and are asymmetrically placed within the blastoceloic cavity and eventually develops into an embryo

Answer 8

inner cell mast (embryoblast )

Question 9

implantation occurs in the – which is a characteristic of species and on day —-

Answer 9

• untrun tissue contact
• day 6 and 7

Question 10

trophoblast and the uterine endometrium epithelium come into contact and the opposing microvilli interlock or fuse which is called —
the close contact induces —- and —- in the underlying endometrial stromal tissue

Answer 10

attachment , vasulatization , differentiation

Question 11

the two types of implantation:
humans, primates , animals are —
for succesful implantation to occur the endometrial walk of the uterus must be primed by hormones ——

Answer 11

• invasive and non inaseve
• invasive
  -progestren and oestrogen