Endo 11: endocrinology of pregnancy Flashcards
Most tubular fluid = reabsorbed in the ________ + _______ under the control of oestrogen
Most tubular fluid = reabsorbed in the RETE RESTIS + EARLY EPIDIDYMIS under the control of oestrogen
Where is oestrogen mainly produced by?
sertoli cells.
nutrients = secreted into epididymal fluid to:
- provide energy for impending possible journey
- to coat surface of spermatozoon
–> nutrients = secreted under influence of androgens
What does semen contain?
- spermatozoa
- seminal fluid
- leucocytes
- potentialy virus e.g HIV
Where does seminal fluid mainly come from?
mainly from accessory sex glands
- seminal vesicles
- prostate
- bulbourethral glands
small contribution from epididymis
What 3 stages are involved in the capacitation of sperm?
- loss of glycoprotein coat
- change in surface memb characteristics
- development of whiplash movements of tail
Where does capacitation of sperm take place in?
takes place in ionic + proteolytic environment of the fallopian tube
Capacitation is dependent on 2 things.
what are the 2 things?
- oestrogen dependent
- Ca2+ dependent
What causes calcium dependent acrosome reaction?
- sperm approaches ovum
- spermatozoon binds to ZP3 glycoprotein on zona pellucida (outer layer of ovum)
- once bound –>progesterone stimulates Ca2+ influx into the spermatozoon
- causes Ca2+ dependent acrosome reaction
What happens after Ca2+ dependent acrosome reaction?
- enables exposed spermatozoon recognition site to bind to 2nd glycoprotein ZP2
- once bound –> acrosome released enzymes
- allows penetration of zona pellucid
- so head of spermatozoon can enter the ovum .
Fertilisation results in expulsion of ______________
Fertilisation results in expulsion of 2nd polar body
what happens in zonal reaction after fertilization?
- ca2+ dependent process:
- cortical granules release molecules that degrade the zona pellucida
- which prevents binding of other sperms
- when diploidy = established, zygote starts dividing to form initial 2-cell conceptus
Describe the development of the Conceptus
- conceptus continues to divide as it moves down fallopian tube –> to uterus (3-4 days)
- it receives nutrients from uterine secretions
- and this free living phase can last for 9-10 days
- the conceptus undergoes compaction to form a 8-16 morula
- then it becomes a blastocyst
inner cell mass of blastocyst becomes:
inner cell mass of blastocyst becomes: the embryo
Trophectoderm of blastocyst becomes:
Trophectoderm of blastocyst becomes: the chorion –> which later becomes placenta
What are the 2 phases of implantation?
- attachment phase
2. decidualisation phase
What happens in the attachment phase?
- outer trophoblast cells come into contact with the uterine surface epithelium
What happens in the decidualisation phase?
“endometrial changes due to progesterone”
- glandular epithelial secretion
- glycogen accumulation in stroll cell cytoplasm
- growth of capillaries
- increased vascular permeability
implantation requires _________ domination in presence of _________
implantation requires progesterone domination in presence of oestrogen
What are the 2 molecules important for attachment/ implantation of ovum?
Leukemia Inhibitory Factor (LIF):
- -> from endometrial secretory glands
- -> stimulates adhesion of blastocyst to endometrial cells
Interleukin-11 (IL-11) :
- -> released from endometrial cells
- -> released into uterine fluid
What factors are involved in decidualisation?
- IL-11
+histamine, TGFB
In the first 40 days of pregnancy:
- progesterone + oestrogen = produced in ______ _______
from day 40:
In the first 40 days of pregnancy:
- progesterone + oestrogen = produced in CORPUS LUTEUM (triggered by hCG)
- -> essential for development of fetoplacental unit
- -> inhibits LH + FSH
from day 40:
- placenta takes over
Describe the production of oestradiol in the placenta
- mother provides pregneolone as precursor
- -> which leads to progesterone
- progesterone leads to steroid production by foetus
- maternal + foetal adrenals produce precursor DHEAS
- which is taken up by placenta
- to produce oestradiol
Why are levels of oestradiol / oestrogen not a useful indicator of the baby’s health?
- because estradiol /oestrogen also comes from the mother as well
