Coitus and conception Flashcards
How long does sperm production take?
74 days
50 in seminiferous
12-26 in the epididymis
Define reproduction
The formation of a unique individual from gametes
What is the normal volume of ejaculate?
2-4ml
What is considered a normal sperm count?
between 20-200x10^6
What is the normal amount of abnormal sperm?
<30%
What are the phases of coitus
Excitement
Plateau
Orgasm
Resolution
What happens to a woman during sex?
blood engorgement mucous secretions increased hr and rr and bp muscle contraction flushed face vaginal expansion
What mucous does oestrogen encourage?
Thin, clear, alkaline
What mucous does progesterone encourage?
Thick, acidic, cloudy
What branch of the ANS causes an errection?
Parasympathetic via the pelvic nerve
Explain what happens to cause an errection
Increased calcium - NOS - NO - vasodilaltor
cGMP - ca into cellular stores - actin and myosin cross link inhibition
Central arteries in corpus cavernosum engorge with blood and the ischiocavernosum and the bulbospongiosum compress veins
What are the common causes of erectile dysfunction?
Vasomotor DM and hypertension Drugs and alcohol Psychological Tear in corpus cavernosum
What does viagra do?
Inhibits the breakdown of the cGMP, maintaining errection
What is emission?
The movement of ejaculate into the prostatic urethra before an errection occurs
why coitus interruptus doesnt work
How does ejaculation occur?
Sympathetic
Pudendal nerve
Contraction of glands, internal urethral spinchter, errectile tissue
What is a dry ejaculation?
When the internal spinchter doesnt contract and it goes into the bladder and no ejaculation at end of penis
What happens to sperm after it enters the female?
Coagulates to prevent leakage
Then proteolytic enzymes break it down
Capacitation
Acrosome reaction
What is capacitation
Removal of glycoprotein coat
Changes from beat movement to whip movement
Explain the acrosome reaction
Removal of acrosome enzymes act on zona pellucida sperm fuses, contents enter via exocytosis fusion and further binding formation of a zygote
How is polyspermy blocked?
ZP hardens and produces factors that will prevent it
How long is the egg viable for?
approx 36 hours
only alive for 24 but the sperm is able to survive for longer which enhances the fertile period
When is the best time for coitus in order to impregnate a woman?
1 day before ovulation
