Endocrinology of Pregnancy Flashcards
What is induced by oestrogen and androgens in the male reproductive tract
oestrogen - Tubular fluid reabsorption
Androgens - nutrients (e.g. fructose) and glycoprotein secretion into epididymal fluid
What is semen made up of
Spermatozoa (15-120 million/ml)
Seminal fluid (2-5ml)
Leucocytes
Potentially viruses e.g. hepatitis B, HIV
What proportion of spermatozoa enter the ovuum
1/100 enter the cervix
1/10,000 cervix to ovum
1/million reach ovum
Where is seminal fluid produced
Mainly from accessory sex glands:
seminal vesicles
Prostate
Bulbourethral glands
Small contribution from epididymis/testis
Describe the capacitation of sperm
Achieves fertilising capability in the female reproductive tract
Takes place in ionic & proteolytic environment of the Fallopian tube
Oestrogen-dependent
Ca2+-dependent
What occurs in the capacitation of sperm
- Loss of glycoprotein coat
- Change in surface membrane characteristics
- Develop whiplash movements of tail
Describe the acrosome reaction
- Sperm binds to ZP3 (sperm receptor)
- Ca2+ influx into sperm (stimulated by progesterone)
- Release of hyaluronidase + proteolytic enzymes from acrosome
- Spermatozoon penetrates the Zona Pellucida
Where does fertilisation occur and what does it trigger
Fallopian tube
Triggers a cortical reaction
Cells from haploid to diploid
What happens in the cortical reaction
Cortical granules release molecules which degrade zona Pellucida (e.g. ZP2 + 3)
Prevents further sperm binding - no receptors
Describe the development of conceptus
Continues to divide as it moves down Fallopian tube to uterus (3-4 days)
Receives nutrients from uterine secretions
This free-living phase can last for ~ 9-10 days
Describe the process of implantation and what does it require
- Attachment phase - outer trophoblast cells contact uterine surface epithelium
- Decidualisation phase - changes in underlying uterine stromal tissue (within few hours)
Requires progesterone domination in the presence of oestrogen
Which molecules are involved in the attachment process
Leukaemia inhibitory factor (LIF) from endometrial secretory glands stimulates adhesion of blastocyst to endometrial cells
Interleukin-11 (IL11) from endometrial cells is released into uterine fluid and may be involved
HB-EGF
What endometrial changes are stimulated by progesterone
Glandular epithelial secretion
Glycogen accumulation in stromal cell cytoplasm
Growth of capillaries
Increased vascular permeability (→oedema)
Which factors are involved in endometrial changes due to progesterone
Interleukin-11 (IL11)
Histamine
Prostaglandins
TGF-beta (angiogenesis)
What are the hormone changes during pregnancy
Early rice in human chorionic gonadotrophin
Slow rises in Progesterone, oestrogen and human placental lactogen which peak later (in order of height of peak)
Describe progesterone and oestrogen producing in the first 40 days of pregnancy
Produced in the corpus luteum, stimulated by human chorionic gonadotrophin
Essential for developing fetoplacental unit
Inhibits maternal LH and FSH (-ve feedback)
What is human chorionic gonadotrophin produced by and what does it act on
Trophoblasts
Acts on LH receptors
Describe progesterone and oestrogen producing after the first 40 days of pregnancy
Placenta takes over production
Describe those oestrogen and progesterones are produced for the foetus by the mother
Mother cholesterol -> pregnenolone -> DHEAS
DHEAS produce by mother, adrenals and liver.
What is the significance of DHEAS IN pregnancy
Maternal and fetal DHEAS is converted into oestrogen
Produced by the adrenal glands and liver of the foetus from pregnenolone
Which maternal hormones increase in pregnancy
ACTH Adrenal steroids Prolactin IGF1 (stimulated by placental GH-variant) Iodothyronines PTH related peptides
Which maternal hormones decrease in pregnancy
Gonadotrophins
Pituitary GH
TSH
Describe endocrine control of parturition (labour)
Foetal oestrogen, Maternal cortisol and Maternal oxytocin binds to the oxytocin receptor
Causes uterine myometrial contraction, cervical dilation and milk ejection
What does oxytocin stimulate
Uterine contraction
Cervical dilation
Milk ejection
