Getting Pregnant Flashcards
What is the role of the seminal plasma secreted in semen
Transport medium
Nutrition
Buffering capacity against acidic vagina
Role for prostaglandins in stimulating muscular activity in female tract
Where does the final maturation of sperm take place
In the epididymis - spermatozoa become mobile after maturation
What are the phases in sexual response in humans
Excitment phase
Plateau phase
Orgasm phase
Resolution phase
What are the phases in the male sexual response
Erection
Emission
Ejaculation
What are the stimulants and efferents for erection
Stimulants - psychogenic and tactile
Efferents - somatic and autonomic efferents. Pelvic (PNS) and pudendal (somatic) nerves
What causes an erection - what does it require
Efferents cause haemodynamic changes in erectile tissue
Erection requires: sinusoidal relaxation, arterial dilation and venous compression
Venous compression occurs as erectile tissue expands and pushes against tunica albuginea -> compresses veins within erectile tissue
Describe the neurophysiology of an erection
Inhibition of sympathetic arterial vasoconstrictor nerves, activation of PNS, and activation of non-adrenergic, non-cholinergic autonomic nerves to arteries resulting in NO release
NO is released from endothelial cells due to ACh (M3 receptor) -> NO diffuses to vascular SM and causes vasodilation
Describe emission and ejaculation
Emission and ejaculation are under sympathetic control
Emission - movement of semen into prostatic urethra due to contraction of smooth muscle in prostate, vas deferens and seminal vesicles
Ejaculation involves contraction of glands and ducts and contraction of internal bladder sphincter (prevents retrograde ejaculation)
What is the time period of the fertile window
Sperm are viable for 48-72hrs
Oocytes are viable for 6-24hrs
Where does fertilisation occur
Fertilisation occurs in ampulla of uterine tubes
Describe the steps in fertilisation
Sperm push through corona radiata -> sperm surface receptor binds to ZP3 glycoprotein of zona pellucida
Binding triggers acrosome reaction - release of enzymes that digest zona pellucida and allows sperm to fuse membranes with oocyte
Cortical reaction occurs after fusion of membranes - reaction changes oocyte membrane to prevent further sperm fusing to oocyte
Series of Ca waves are activated following fusion causing meiosis II to resume and complete -> sperm and oocyte pronuclei come together and zygote forms
When oocytes are fertilised in vitro, when are they implanted in the uterus
Oocytes are allowed to divide to the 4 or 8 cell stage and then the morula is transferred to the uterus for implantation
What is PGD
Pre-implantation genetic diagnosis
Used to test for serious heritable conditions prior to transfer of morula to uterus
