Endocrinology 11 - Endocrinology of Pregnancy Flashcards
Where is seminal fluid from?
- Small contribution from epididymis or tesis
- Acessory sex glands - seminal vesicles, prostate, bulbourethral glands
Describe the process of capacitation of sperm
- Maturation and activation
- Loss of glycoprotein coat
- Change in surface membrane characteristics
- Develop whiplash movements of tail
- Achieved in the fallopian tube (oestrogen and Ca2+ dependent)
Describe the acrosome reaction
- Sperm binds to ZP3 (sperm receptor)
- Calcium influx into the sperm (stimulated by progesterone)
- Release of hyaluronidase and proteolytic enzymes from the acrosome
- Spermatozoon penetrates the zona pellucida
Describe the process of fertilisation
- Occurs within the fallopian tube
- Triggers cortical reaction
- Cortical granules release molecules which degrade zona pellucida (prevents further sperm binding)
- Haploid to diploid
Describe the development of conceptus
- Continues to divide as it moves to the uterus
- Recieves nutrients from uterine secretions
- Can last for 9-10 days
Describe the process of implantation
- Attachment phase (outer trophoblast cells contact uterine surface epithelium)
- Decidualisation phase (changes in underlying uterine stromal tissue)
- Requires progesterone domination in the presence of oestrogen
Describe the process of attachment phase
- Attachment of blastocyst to endometrial lining to trigger implantation
- Outer trophoblast cells contact uterine surface endothelium
- Leukaemia inhibitory factor from endometria secretory glands stimulates adhesion of blastocyst to endometrial cells
- Interleukin 11 from endometrial cells is released into uterine fluid
Describe the process of decidualistion
- Trophoblast migration into the endometrium and maternal spiral arteries
- CHanges in underlying uterine stromal tissue within a few hours of contact (progesterone domination + oestrogen presense)
- Endometrial changes
- Interleukin 11, histamine and prostagladins are involved
Describe progesterone and oestrogen production during pregnancy
- In the first 40 days, produced by the corpus luteum, which inhibits maternal LH and FSH
- From day 40, the placenta takes over production
Describe the physiological changes in maternal hormones
Increase in
- ACTH
- Adrenal steroids
- Prolactin (test visual fields in pregnant women)
- IGF1
- Iodothyronines (due to hCG)
- PTH related peptides
Decrease in
- Gonadotrophins
- Pituitary GH
- TSH
Describe the endocrine control of partruition
- Oestrogen, cortisol and oxytocin are the key hormones
- Oxytocin induces uterine contraction, cervical dilation and milk ejection
Describe the endocrine control of lactation
- Prolactin stimulates milk synthesis (adenohypophysis)
- Oxytocin stimulates milk ejection (neurohypophysis)
Which hormone becomes important in pregnancy?
hCG - human chorionic gonadotrophin
Which factors are involved in implnatation?
- IL11
- LIF (leukaemia inhibitory factor)
- Progesterone
Describe the hormone changes and effects during pregnancy
- hCG goes up initially to maintain the corpus leuteum, and then decreases when oestrogen and progesterone production is taken over by the placenta (human chorionic gonadotrophin)
- Human placental lactogen (metabolism and insulin resistance, so the nutrients go to the baby) increases
- Oestrogen and progesterone increase
How are progesterone and oestrogen produced during pregnancy?
- Maternal and fetal DHEAS are the main source of the substrates that are then converted to the oestrogens
- Made from cholesterol and pregnenolone
How does prolactin inhibit the reproductive axis?
Via kisspeptin production - if there is not enough leptin kisspeptin will be inhibited as well
List the stages of fertilisation
Acrosome and cortical reaction
List the stages of implantation
Attachment and decidualisation
Describe the process of spermatogenesis
- Spermatogonia to primary spermatocyte
- Divides to secondary spermatocyte (haploid - Meiosis I)
- Divides to spermatid (meiosis II)
- Finally to spermatozoa
List the stages of sperm maturation
- Capacitation
- Acrosomal Reaction
- Fertilisation
List the endometrial changes in the decidualisation phase
- Glandular epithelial secretion
- Glycogen accumulation
- Growth of capillaries
- Increased vascular permeability
