Fertility And Infections Of The Reproductive Tract Flashcards
Why are clotting factors and proteolytic enzymes both found in semen?
Clotting factors ensure deposition of semen in the female reproductive tract, while proteolytic enzymes then break down the clots to allow the motile sperm to make their way to the ampulla for fertilisation
What nervous innervation is erection controlled by?
Somatic and autonomic efferent of the parasympathetic nervous system.
Pelvic nerve - parasympathetic
Pudendal nerve - somatic
What three physiological processes are required to sustain erection?
Sinusoidal relaxation,
Arterial dilation,
Venous compression.
what chemical mediator controls erection?
How is it released?
Nitric oxide.
1.Post ganglionic fibres release Ach
2. Ach binds to M3 receptors and activates nitric oxide synthase
3. NO diffuses into vascular smooth muscle and causes vasodilation.
(NO can also be released directly by nerves)
Where are some causes of erectile dysfunction?
Descending inhibition of spinal reflexes eg spinal nerve compression,
Tears in corpora cavernosa,
Vascular disease,
Drugs.
How does viagra cause prolonged erections?
Slows rate at which cGMP degrades, causing vasodilation to continue long after exposure to nitric oxide
Which branch of the nervous system controls ejaculation?
Sympathetic nervous system
Why does the internal sphincter of the bladder close during ejaculation?
Prevent retrograde ejaculation into the bladder
How can quality of mucus indicate female fertility?
Thick and acidic likely less fertile, as progesterone is actively attempting to prevent entry of sperm
What is capacitation?
Further maturation of sperm in the female reproductive tract.
Tail changes to whip like motion, sperm cell membrane changes to allow the acrosome reaction and fusion with the oocyte.
What is the fertile window for spermatozoa in the female reproductive tract?
48-72 hours, meaning fertile period includes sperm deposition up to 3 days before day of ovulation
What is the acrosome?
Outer shell of sperm derived from golgi, containing enzymes necessary for fertilisation
What is the acrosome reaction?
Sperm push through corona radiata and bind with the surface protein ZP3 to the zona pellucida, causing release of enzyme ps and digestion.
After penetration, what mechanism ensures no more sperm enter the oocyte?
Calcium dependant exocytosis of protease containing cortical granules from the ovums plasma membrane, digest other sperm. Called the cortical reaction.
What effect do calcium waves following fusion have on the pronuclei?
Pronuclei move together and meiosis 2 occurs, forming mitosis spindle for cleavage.
After the first differentiation, forming inner and outer cell masses, what does the zygote become?
Blastocyst. This hatches from the zona pellucida and implants upon the uterine surface
What makes chlamydia an obligate intracellular bacterium?
Able to prevent fusion of phagosome after phagocytosis so can replicate within the phagocyte
What are common signs of chlamydia infection?
Males - testicular swelling and pain, dysuria
M+F - dyspareunia, discharge, often asymptomatic.
What are common symptoms associated with gonorrhoea?
Thick yellow discharge
Dysuria in men
Only 50% of women present with symptoms compared to 90% men
How are gonorrhoea and chlamydia investigated?
Screening,
Gonorrhoea- urethral swab in men or urine cultures
Chlamydia - NAAT - nucleic amplification studies
When might discharge in a woman be physiological?
How would you be able to tell?
Secretory phase under the influence of progesterone, cervical mucus is thickened.
Ask - cyclical? Colour? No other symptoms suggesting systemic infection?
What is trichomonas vaginalis?
Protozoa found in the vagina at higher than normal physiological pH. Cause yellow offensive smelling discharge, eradicated by metronidazole.
What causes bacterial vaginosis?
Gardnerella vaginalis or other organism proliferation following a decrease in normal lactobacillus levels. Often brought about by excessive cleaning
What may predispose a woman to developing infection with Candida albicans?
Immunosuppressants
Diabetes
Rise in oestrogen (oral contraceptive)
Antibiotic use.
