S6 L1 Sex and Fertilisation Flashcards
Recap:
Menstrual cycle
Recap:
Spermatogenesis
Recap: Maturation of sperm in the epididymic - the sperms journey
Semen
- What does this consists of?
- Function of seminal plasma… Male
- Female, what does oestrogen and progesterone provide…
Seminal plasma
- 3 parts and explain each of them
Where are the different glands?
Normal values for semen analysis:
- Volume of ejaculate
- pH
- Sperm count
2-6ml
pH 7-8
>20 million/mL
There are other things too: e.g. viscosity, motility, morphology
Human sexual response
- 4 responses and explain them
- Explain the cycle
Male sexual response - Erection
- Stimulants
- Efferents
- What happens due to the efferents?
What does the erection of the penis require anatomically?
Parasympathetic innervation of the penis
- Steps of this pathway
Neurophysiology of erection
Role of Nitric Oxide in an erection
Erectile dysfunction causes
Male - Emission and Ejaculation
- Under which control?
- What are each of these terms?
- More detial: Process of ejaculation
Under sympathetic control
• Emission:
• Movement of semen into prostatic urethra
• Contraction of SM in prostate, vas deferens and seminal vesicles
• Ejaculation:
• Expulsion of semen
Expulsion of semen through:
• Contraction of glands and ducts (smooth muscle)
• Bladder internal sphincter contracts
• Preventing retrograde ejaculation
• Rhythmic striatal muscle contractions (pelvic floor, and perineal muscles ischiocavernosus, bulbospongiosus)
Summary of Autonomic control of male sexual function:
- Erection
- Ejaculation
Female:
Reminder of Oestrogen and Progesterone’s role
Menstrual cycle changes in female tract
- Character of the cervical mucus changes over the course of the menstrual cycle
- Oestrogen causes the mucus to be…
- Oestrogen and Progesterone causes the mucus to be…
Physiological changes within the female during sexual activity
Semen deposition
- Where is it deposited?
- Where does it have to move to?
Capacitation
- What is this?
- What happens?
Fertile window
- Women
- Men
•14 day period of presents of corpus luteum
• Once coitus has taken place, there is a further window:
- Spermtozoa 48 -72hr
- Oocytes 6 –24 hr (max)
• Fertile period: sperm deposition up to 3 days prior to ovulation or day of
ovulation
• Gamete transport
- Oocyte: beating cilia & peristalsis of uterine tube
- Sperm: own propulsion
Overview of events in fertilisation
- 4 events
- Occurs normally in the ampulla of the uterine tubes
- Requires loss of sperm outer shell (acrosome), loss of the acrosome of the male sperm allows it to penetrate
- Penetration of ovum membrane, fusion of ova and sperm membrane
- Eventual formation and fusion of pronuclei
Fertilisation
The acrosome:
- What is this
- What does it contain
- Describe the whole acosome reaction
Don’t look at the picture attached to this slide until looked at last slide
- Derived from golgi region of developing spermatid
- Contains enzymes
- Necessary for fertilisation
- Acrosome contains enzyme that are crucially important
Fertilsation:
- How is only one sperm able to fertilse the egg?
Fertilisation: Completion of meiosis II
- What is this?
- Describe what happens?
Next steps:
- Morula
What is Assisted Reproductive Technology (ART)?
Morula:
Each cell at this stage of development is TOTIPOTENT
• i.e. has the capacity to become any cell type
ART:
• Oocytes are fertilised in vitro and allowed to divide to the 4-or 8-cell
stage
• The morula is then transferred into the uterus
• Pre-implantation Genetic Diagnosis (PGD)
• a cell can be safely removed from the morula and tested for
serious heritable conditions prior to transfer of the embryo into
the mother
Next step:
- Blastocyst and hatching
- Implantation
