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what are the major sequence of events following deposition of spermatozoa in female tract
1. immediate transport
what species ejaculate into the cranial vagina?
cow, sheep, rabbit, primates, dog and cat
what species ejaculates semen into the cervix?
in what species does the semen get squirt through the cervical lumen during copulation?
in what species do most of the ejaculate gains entrance into the uterine lumen?
dog pig and horse
what species ejaculates in a series of jets?
what is unique about the first 3-4 squirts of semen in the stallion?
it is high in pressure, 80% of the spermatozoa
what is unique about the last 5-8 squirts of semen in the stallion?
it is lower in pressure and contains fewer sperm
spermatozoa are lost from the female tract by:
phagocytosis by neutrophils and retrograde transport
what species have a relatively solid vaginal plug that is externally visible following copulation?
mice and rats
true or false: domestic animals have a conspicuous vaginal plug
what is the job of neutrophils?
poised to attack foreign materials that are introduced into the female reproductive tract, including spermatozoa (live and dead)
spermatotozoal transport consists of a:
rapid phase and a sustained phase
after a few minutes after copulation where can the spermatozoa be found?
in the oviducts
is the functional importance of the rapid phase obvious?
no, no idea
out of the two phases of spermatozoal transport which one is more important?
the sustained phase
what happens in the sustained phase?
sperm moves in to the isthmus and attaches to the oviductal epithelium. the sperm can attach to the ENTIRE oviduct
what is the importance of sperm docking?
it is crucial to sperm survival because it elicits a signal cascade in the sperm that promotes viability. without docking the sperm would die within 6-10 hours after insemination
what is rapid transport of spermatozoa the primary result of?
the elevated tone and motility of muscular of the female tract
when estradiol is high what happens?
PGF2a PGE1 are also high
what do prostaglandins in semen do?
they cause increased tone and motility of the uterus and/or the oviduct
in camelids what causes ovulation?
seminal plasma components
what is a major barrier to spermatozoal transport and it can also serve as a reservoir for spermatozoa?
what are the two types of cervical mucus in the cow?
sialomucin and sulfomucin
what is sialomucin?
a mucuc of low viscosity, it is produced by cells in the basal areas of the cervical crypts
what is sulfomucin?
produced in the apical portions of the cervical epithelium covering the tips of the cervical folds. quite viscous
the low viscousity environment of the deeper cervical crypts create what?
a privileged pathways
for maximum fertility to be achieved, what must happen to the spermatozoa?
it must reside in the female reproductive tract for a minimum period of time,
what happens to the spermatozoa when it is in the reproductive tract?
the spermatozoa undergoes changes that makes them fertile. these changes are known as spermatozoal capacitation
location of capacitation happens where in the reproductive tract?
it varies within species
is the stripping process of capacitation understood?
can the process of capacitation be reversed?
where does acquisition of hyperactive motility occur?
in the oviduct
how does the motility pattern change after acquisition?
from a linear motility to a frenzied dancing motion
what is thought to come about hyperactive motility?
to facilitate sperm oocyte contact
binding to the zona pellucid requires?
specific zona binding proteins on the spermatozoal membrane
what are the three glycoproteins or the zona pellucida?
zona proteins 1, 2, 3 ZP1 ZP2 ZP3
what zona proteins are structural proteins providing structural integrity of the zona?
ZP1 and ZP2
what does ZP3 do?
acts like a receptor for a hormone
how many zona binding sites are there?
what are the two binding sites called?
primary zona binding region & acrosome reaction promoting ligand
what does the primary zona binding region do?
is responsible for adherence of spermatozoa to the zona pellucida
what does the acrosome reaction promoting ligand do?
the ZP3 molecules brings to this region and signal transduction occurs
what is the acrosomal reaction?
an orderly fusion of the spermatozoal plasma membrane and the outer acrosomal membrane
what is vesiculation?
when the two membranes fuse, many small vesicles are formed
what causes damages to the acrosome membranes?
cooling quickly, osmotic pressure changes, sudden heating, or marked changes in pH
what does damage to the acrosome membrane causes?
the premature loss of acrosomal contents and such sperm cannot accomplish fertilization
release of acrosomal enzymes allows for?
the spermatozoon to digest its way through the zona pellucida
what is an acrosin?
one enzyme that is released from spermatozoa during the acrosomal reaction. enhances the sperm's ability to bind to the zona
what is a proacrosin?
an inactive acrosin. has a strong affinity for zona. it becomes active when sperm begins to penetrate the zona pellucida
what does fertilization require?
the fusion of the equatorial segment and the oocyte plasma membrane
what does the cortical reaction prevent?
penetration by additional spermatozoa
when does exocytosis happen?
after membrane fusion between the oocyte and spermatozoon, the cortical granules undergo this
what results from exocytosis?
the zona block
what is prevented by the zona block?
what is polyspermy?
the fertilization of an oocyte by more than one spermatozoon which results in embryo death
what also prevents polyspermy?
pronuclie formation allows the male and female DNA to:
form a single nucleus
what must be done to the nucleus of the male DNA in the oocyte?
they must condense so it can pair up with the females
what is primary reducing agent for the nucleus?
what is superfecundation?
multiple fathers in a litter. spermatozoa from all males are eligible to fertilize oocytes
what percentage of the menstrual cycle have the potential to generate a pregnancy?
at bat =
1 opportunity to achieve pregnancy
batting average =
probability of becoming pregnant
good at bat =
many swings but depletes extragonadal reserves
what is transcervical insemination?
semen is delivered using a pipette to penetrate and bypass the cervix
what is intracervical insemination?
the pipette is positions within the cervix and semen is delivered into the cranial half of the cervix and flows directly into the uterine horns
what is intravaginal insemination?
semen is deposited into the cranial vagina
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