Endocrinology of Pregnancy Flashcards
Inside to outside layers of the testis, what cells and what’s made there?
Inside is spermatozoa are formed, next layer outwards is the Sertoli cells which make sperm, and the outermost layer are the Leydig cells which make testosterone
Sertoli cells make..
sperm
Leydig cells make…
testosterone
Sertoli cells are stimulated by …
FSH
Leydig cells are stimulated by …
LH
What do men need oestrogen for and what is it made by
Converted from testosterone by aromatase and is needed for bone
Features of aromatase deficiency in males (3)
- Tall oestrogen needed to close growth plates
- Infertility or low sperm count
- Osteoporosis Fractures from a young age
Features of aromatase deficiency in females (4)
- Virilisation -> Changes that make a female develop male characteristics
- Hirsutism
- Deepening of the voice
- Amenorrhoea
Where does the spermatozoa travel from testes?
Oviduct
Where is seminal fluid produced (4)
- Small contribution from the epididymis/testis
- MAINLY from the accessory sex glands:
Seminal vesicles
Prostate
Bulbourethral glands
What happens to sperm to gain fertilising ability? (3)
- Loss of glycoprotein ‘coat’
- Change in surface membrane characteristics
- Develop whiplash movements of the tail
Where is a sperm capacitated
- Takes place in ionic and proteolytic environment of the Fallopian tube
What is required for sperm capacitation (2)
- Oestrogen dependent
- Ca2+ dependent
What receptor do sperm bind to on the ovum
- Sperm binds to ZP3 (glycoprotein receptor on zona pellucida of ovum)
what happens when sperm binds to the ZP3 receptor on the ovum? what stimulates this?
- Ca2+ influx into the sperm (stimulated by progesterone)
What enzyme breaks down the polysaccharide of the zone pellucida
hyaluronidase
What breaks down the zone pellucida
- Release of hyaluronidase (breaks down polysaccharides) and proteolytic enzymes (break down protein)
Describe the acrosome reaction starting with sperm binding
- Sperm binds to ZP3 (glycoprotein receptor on zona pellucida of ovum)
- Ca2+ influx into the sperm (stimulated by progesterone)
- Release of hyaluronidase (breaks down polysaccharides) and proteolytic enzymes (break down protein)
- Spermatozoon penetrates zona pellucida
Where in the vagina does fertilisation occur
Fallopian tube
What reaction does fertilisation trigger
cortical reaction
What happens in the cortical reaction
Cortical granules release molecules which degrade the zona pellucida (e.g. ZP2/ZP3) PREVENTS FURTHER SPERM FROM BINDING
How long does it take for the zygote to move down Fallopian tube to uterus
3-4 days
How long is the zygote a free living unbound ting
About 9-10 days
2 phases of implantation?
ATTACHMENT phase
DECIDUALISATION phase
What happens during the ATTACHMENT phase
Outer trophoblast cells contact uterine surface epithelium
Followed by DECIDUALISATION phase
What happens during the DECIDUALISATION phase (brief)
Changes in underlying uterine stromal tissue (within a few hours)- allows it to receive the fertilised egg
Wha hormone is dominant in attachment of the egg to the uterus over what
Progesterone > oestrogen
what is leukaemia inhibitory factor
from endometrial secretory glands (and blastocyst?) stimulates adhesion of blastocyst to endometrial cells
what secretes leukaemia inhibitory factor
endometrial secretory glands
What stimulates adhesion of blastocyst to endometrial cells
leukaemia inhibitory factor
from endometrial secretory glands
(and a bit of IL-11 )
2 hormones involved in attachment phase?
- IL-11 and leukaemia inhibitory factor
decidua is …
thick layer of modified mucous membrane which lines the uterus during pregnancy and is shed with afterbirth
What endometrial changes take place due to progesterone? (4)
Glandular epithelial secretion (nutrients)
Glycogen accumulation in stromal cell cytoplasm (stromal cells are layer under epithelium)
Growth of capillaries (increased blood supply for placenta)
Increased vascular permeability ( Oedema
Factors involved in the endometrial changes of progesterone?
IL-11, histamine, certain prostaglandins, TGFbeta (promotes angiogenesis
hCG is produced by what
Placenta
hCG acts on what receptors
LH receptors
Purpose of hCG?
Acts like a gonadotrophin in the absence of LH/FSH (due to prolactin inhibition)
what does a urine pregnancy test test
hCG
How many weeks does it take for hCG in plasma to peak during prenancy
about 8
What is the dominant reproductive hormone throughout pregnancy
Progesterone
where is PROGESTERONE AND OESTROGEN PRODUCTION in the FIRST 40 DAYS
- Produced by CORPUS LUTEUM (follicle that released the ovum)
what stimulates PROGESTERONE AND OESTROGEN PRODUCTION in the FIRST 40 DAYS
Stimulated by hCG (produced by trophoblasts) and acts on LH receptors
- Essential for developing fetoplacental unit
What cells produce hCG during pregnancy
trophoblasts
From day 40 of pregnancy, where are oestrogens sourced from
Placenta
DHEAS converted by X into oestrogens
Placenta
What produces DHEAS
mother and foetus
What maternal hormones increase during pregnancy (6)
- ACTH- can cause erroneous Cushing’s diagnosis
- Adrenal steroids
- Prolactin If someone has a prolactinoma then you have to use MRI to track prolactinoma size, OR can measure visual fields in each trimester
- IGF1 (stimulated by placental GH-variant)
- Iodothyronines (increased demand for thyroid hormones in pregnancy)
- PTH related peptides
What maternal hormones decrease during pregnancy (6)
- Gonadotrophins
- Pituitary GH
- TSH
During pregnancy this hormone goes up or down: ACTH
Increases
During pregnancy this hormone goes up or down: Prolactin
Increases
During pregnancy this hormone goes up or down: adrenal steroids
Increases
During pregnancy this hormone goes up or down: IGF1
Increases
During pregnancy this hormone goes up or down: Iodothyronines
Increases
During pregnancy this hormone goes up or down: PTH related peptides
Increases
During pregnancy this hormone goes up or down: gonadotrophin
Decreases
During pregnancy this hormone goes up or down: Pituitary GH
Decreases
During pregnancy this hormone goes up or down: TSH
Decreases
What hormones are involved in parturition and ions (4)
calcium, driven partly by oestrogen and inhibited by progesterone, Oxytoxin
What hormone inhibits parturition
Progesterone
What drives parturition (3)
Oxytocin, oestrogen and calcium entry
What hormone promotes milk ejaculation
Oxytocin
What hormone promotes milk syntheiss
prolactin
