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Spermatozoa in the female tract - Coggle Diagram
Spermatozoa in the female tract
After insemination spermatozoa in the female reproductive tract must:
1) transverse the cervix
2) be transported through the uterus to the oviduct
rapid phase
rapid transport of spermatozoa is primarily the result of elevated tone and motility of the muscularis of the female tract
Sustained phase
3) undergo capacitation
4) bind to the oocyte
5) undergo the acrosome reaction
6) penetrate the zona pellucida and fuse with the oocyte plasma membrane
Spermatozoa are lost from the female tract by: phagocytosis by neutrophils, retrograde transport
The cervix is a major barrier to spermatozoal transport and it can also serve as a reservoir for spermatozoa
Spermotozoa must reside in the female tract before they acquire maximum fertility
Artificial inscemination
Transcervical insemination- semen is delivered using a pipette to penetrate and bypass the cervix
Intracervical insemination- In the sow, the insemination pipette is positioned within the cervix and semen is delivered into the cranial half of the cervix and flows directly into the uterine horns
Intravaginal insemination- In dogs and cats semen is deposited in the cranial vagina
Fertilization
acquisition of hyperactive motility occurs in the oviduct
Postcapacitation sequence of events leading to fertilization
Binding of the zona pellucida requires specific zona- binding proteins on the spermatozoal membrane
The acrosomal reaction is an orderly fusion of the spermatozoal plasma membrane and the outer acrosomal membrane
damage to the acrosome membrane and plasma membrane is irreversible. Damage to these membranes is brought about by changes in osmotic pressure, sudden cooling, sudden heating, or marked changes in pH
Release of acrosomal enzymes allows the spermatozoon to digest its way through the zona pellucida
Fertilization requires fusion of the equatorial segment and the oocyte plasma membrane
The cortical reaction prevents penetration by by additional spermatazoa
Pronuclei formation allows the male and female DNA to form a single nucleus
Fertile period varies by species in females
