Pre-fertilisation Sperm Events Flashcards
What are the immediate sperm events?
Very rapid transport to uterus, semen coagulation & loss of spermatozoa
Which part of the spermatozoa is responsible for movement?
Tail (flagellum) – propels sperm 3mm/min
What assists the movement of sperm at ejaculation?
Female tract contractions
What two sections make up the flagella?
Central axoneme & dyneins
What are some of the common tail abnormalities?
Coiled tail, double midpiece, folded tail, detached head
What is the function of prostaglandins in the seminal plasma?
Stimulate muscular activity in female tract
What is the route sperm takes following ejaculation?
Cervix-> uterus ->oviduct
Where does rapid and sustained sperm transport occur?
Uterus through to the oviduct
What is significant about sperm in the dog?
Remain functional for many days (uterine sperm reservoir)
How many sperm reach the oviduct and what occurs there?
1% sperm, sperm binds to oviductal cells (prolong lifespan), sperm released around ovulation, main site of capacitation (assists with the release of sperm)
What is the function of capacitation?
Detachment of the sperm from the oviductal epithelium, exposure of surface proteins that can bind to oocyte, enables acrosome reaction
What are the three glycoproteins that make up the zona pellucida?
ZP1 (minor component), ZP2 (structural component), ZP3 (“receptor”)
What are the four steps of fertilisation?
Binding of spermatozoa to ZP ->acrosomal reaction ->penetration through ZP ->fusion of plasma membranes
What happens once the spermatozoa head penetrates ZP?
Calcium mobilisation is induced within the oocyte
What induces the completion of meiosis II?
Sperm binding to oocyte
