Exam - Fertilization Flashcards
what is the first trap of sperm transport
cervical folds
the glands of the cervix produce whaat
acidic mucus
what does the acidic mucus do
prevents entry of microorganisms
what acts as the physical barrier in cervix
fold + mucus = plug
when is there a change in mucus composition
during estrus E2
what changes occur to the mucus during estrus
less acidic
thinner and more elastic
forms strands or “privilege pathways PP” to allow sperm to pass
when does P4 return mucus to acidic barrier
after ovulation
what is the dose of semen in artificial insemination of cows
20x10^6 spermatozoa or less
where is the semen deposited in artificial insemination of cows
body of the uterus (first AI)
anterior cervix (repeat AI)
what is the primary source of loss with AI in cows
retorgrade flow
wrong horn
what are the major reason for AI failure in cows
cow not in heat
poor technique
early embryonic mortality
what does effective sperm transport require
contractions of the female reproductive tract
process of contractions
mating -> nervous stimulation-> posterior pituitary gland - > oxytocin –> milk ejection/increased contractions of uterus/oviducts by high ratio E2:P2
what must happen to ejaculated spermatozoa from domestic species
it must be capacitated in female tract
what does the loss of surface proteins acquired during epididymal transit equal
reorganization of plasma membrane lipid composition
why is motility important for final approach to oocyte
hyperactivation
where is the capacitation initiated
in uterus at the utero-tubal junction
what is required following capacitation
intact acrosomes for acrosome reaction during fertilization
where must capacitation be performed
in vitro for IVF
in the oviduct, what are well developed in the infundibulum and ampulla
internal mucosa and lamina propria
what do the internal mucosa and lamina propria possess
ciliated epithelium beat and move fluid towards uterus
what do secretory cells in oviduct (peg cells) do
secrete nutrients for oocyte and antimicrobial
what is the oviduct made of
smooth muscle layers
what are the important steps required for fusion during fertilization
penetration of the corona radiata
perforation of the zone pellucid = acrosome reaction
transfer of the nucleus
what is the corona radiate
a layer of granulosa cells
how do granulosa cells get dissociated
several spersm reach the corona radiata and release enzymes to dissociate - sacrificing themselves
what does one lucky seem reach
the zona pellucida
what is the acrosomal reaction
membrane proteins on the sperm cell surface bind glycoproteins of zone pellucida
where does fertilization occur
junction of ampulla+isthmus
when does the oocyte complete meiosis
as the sperm enters
what is the zygote
both haploid pronucleus fuse to form a diploid fertilized egg
how long after sperm entry is a zygote formed
within 12h
how large is a zygote
giant
what happened tot he zygote
it divides every 24h to form smaller cells through cleavage
when does the morula enter the uterus
after 4-5 days
what does the unattached embryo convert to
a blastocyst
how foes the unattached embryo convert to a blastocyst
inner cell mass will form embryo
trophoblast will form the amnion and the chorioin
cavity = blastocoele
