Endocrinology of pregnancy Flashcards
What hormone induces tubular fluid reabsorption?
Oestrogen.
What hormones induce nutrients and glycoprotein secretion into epididymal fluid?
Androgens.
What distance does the spermatozoa travel from testis to oviduct?
100,000x its length, equivalent to 150km for a 1.5m human.
What is the spermatozoa concentration in semen?
15-120 million/ml
What is the volume of seminal fluid in semen?
2-5ml
What are the contents of semen?
Spermatozoa
Seminal fluid
Leucocytes
Potentially viruses, e.g. hepatitis B, HIV
What proportion of spermatozoa in ejaculate enter the cervix?
1%
What proportion of spermatozoa that entered the cervix reach the ovum?
0.01%
What proportion of spermatozoa in ejaculate reach the ovum?
1 in a million.
Where is seminal fluid produced?
Small contribution from epididymis/testis.
Mainly from accessory sex glands: seminal vesicles, prostate, bulbourethral glands.
What is capacitation of sperm?
Achieve fertilising capacity in the female reproductive tract.
Loss of glycoprotein coat.
Change in surface membrane characteristics.
Develop whiplash movements of tail.
Takes place in ionic and proteolytic environment of Fallopian tube.
Oestrogen-dependent.
Calcium-dependent.
What is the acrosome reaction?
Capacitated sperm binds to ZP3 (glycoprotein receptor).
Calcium influx into sperm (stimulated by progesterone).
Release of hyaluronidase and proteolytic enzymes.
Spermatozoon penetrates the zona pellucida (glycoprotein coat of ovum).
Where does fertilisation occur?
Fallopian tube
What reaction does fertilisation trigger?
Cortical reaction.
What is the cortical reaction after fertilisation?
Cortical granules release molecules which degrade zona pellucida (e.g. ZP2 and 3), therefore prevents further sperm binding.