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spermatozoa in the female tract - Coggle Diagram
spermatozoa in the female tract
major sequence of events following desposition
3: uterus
capacitation initiated
phagocytosis
4: oviduct
docking to oviductal cell
capacitation completed
hyperactive motility
2: cervix
"privileged pathways"
removal of non-motile sperm
removal of some abnormalities
5: fertilization
acrosome reaction
spermatozoon penetrates oocyte
male and female pronuclei form
1: immediate transportation
phagocytosis
entrance into cervix/uterus
retrograde loss
spermatozoa are lost from the females tract by
phagocytosis by neutrophils
neutrophils are poised to attack foreign materials that are introduced into the female reproductive tract at insemination
retrograde transport
fertilization
involves a series of specific interactions between spermatozoa and the oocyte
acquisition of hyperactive motility occurs in the oviduct. motility pattern changes from a progressive linear motility pattern which they swim in a relatively straight line, into a frenzied dancing motion
postcapacitation sequence of events leading to fertilization
6) sperm engulfed
7) decondensation of sperm nucleus
5) seprm-oocyte membrane fusion
8) formation of male pronucleus
4) penetration of zona pellucida
3) acrosomal reaction
2) binding to zona pellucida
1) hyperactive motility
binding to the zona pellucida requires specific zona-binding proteins on the spermatozoal membrane
spermatozoa are known to contain specific proteins on their plasma membrane surface overlying the acrosome that bind specifically to zona pellucida proteins
release of acrosomal enzymes allows the spermatozoon to digest its way through the zona pellucida
requires fusion of hte equatorial segment and the oocyte plasma membrane
fusion proteins
cortical reaction prevents penetration by additional spermatozoa
after membrane fuision, the oocyte undergoes a series of changes that prepare it for early embryogenesis
polyspermy is prevented by the zona block
polyspermy is the fertilization of an oocyte by more than one spermatozoon which results in embryo death
pronuclei formation allows the male and female DNA to form a single nucleus
the fertile period varies significantly among mammalian females
in most domestic species the period of estrus is less than 24 hours
sperm can remain viable for as lon as 5 to 6 days before oculation in women
fertilization can be accomplished as long as six days after the onset receptivity
superfecudation: spermatozoa from all ales are eligible to fertilize oocytes
batting averages and pregnancies are similar
a good "at-bat" = many swings (bat depletes extragonadal reserves)
a swing = 1 mating
the batting averages = probability of becoming preganant
each "at-bat" = opportunity to achieve pregnancy
delivery of semen to the proper anatomical region of the female tract is required for successful artificial insemination
higher proportion of spermatozoa deposited in the uterus
spermatozoa deposited into only one uterine horn of the cow experience intercornual transport
when AI is performed in the cow and semen is deposited into the cervix, a greater portion of spermatozoa are lost to the exterior than when deposition is in the uterus
different AI techniques in domestic species
intracervical insemination
intravaginal insemination
transcervical insemination