Lecture 8 - Fertilisation In Vivo & In Vitro Flashcards
What is chemotaxis and thermotaxis? Why is it important in the female reproductive system?
- Helps to draw the sperm to the oocyte so it isn’t just randomly swimming
- Thermotaxis: temperature gradient, warmer in fallopian tube (36degrees)
- Chemotaxis: oocyte secretes factors into fallopian tube creating a gradient
What are the 3 processes needed for fertilisation? A.k.a. What 3 things does the sperm have to undergo?
- Sperm capacitation
- Acrosome reaction
- Fusion with oocyte
What is sperm capacitation and how does it occur?
- Functional maturation of the spermatozoon
- As the sperm moves along the fallopian tube there is an increase in Protein Tyrosine Phosphorylation, hyperactivation of sperm motility and preparation for the acrosome reaction
What is the acrosome reaction?
- As the sperm approaches the zona pellucida the membrane surrounding the acrosome fuses with that of the sperm head.
- Acrosomal process comes out and attaches to zona pelluicida
- Plasma membrane of egg and spem head bind allowing sperm nucleus to enter.
What does the fertilisation do to the oocyte in terms of Ca2+?
- Fertilisation causes intracellular Ca2+ oscillations in the oocyte - no Ca2+ oscillations = no embryo development
- The ER in the oocyte is where the Ca2+ is released from
What is ART
Assisted Reproductive Technology
ART - look at lecture slides
Look at pages 14-28 of lecture slides for good understanding of ART (easy to understand)
To mimic the acrosomal reaction what two things need to be added in to ART?
Progesterone & Ca2+ ionophore
What types of signals does the developing embryo get in vivo? Does an in vitro embryo get these same signals? How is this overcome?
Paracrine, autocrine & endocrine. In vitro, only get the autocrine signals (no mother means no paracrine & endocrine signals). Overcome by adding in endogenous & exogenous signals to increase the success rate of ART.
