11) Endocrinology of pregnancy Flashcards
Which enzyme converts testosterone to oestrogen?
Aromatase
2 symptoms of someone with an aromatase deficiency?
Excess testosterone=acne + hirturism
Lack of oestrogen=tall as oestrogen req to close growth plates + osteoporosis
4 components of semen:
12-120million spermatozoa (only 1 million reach ovum)
Seminal fluid
Leucocytes
(viruses)
2 places that produce seminal fluid:
1) epidiymis
2) accessory sex glands e.g. seminal vesicles
5 steps in fertilisation:
Capcitation Acrosome reaction Fertilisation Cortical reaction Implantation (attachment + decidulisation)
What is sperm capcitation with examples of the changes that take place?
Sperm achieving the capability to fertilise an egg
- whiplash tail develops
- loss of glycoprotein coat
Where does sperm capacitation take place?
Fallopian tube
What happens during the acrosome reaction?
When the digestive head of the sperm penetrates the ovum
- Sperm binds to ZP3 receptors on ovum
- Ca2+ influx into acrosome (due to progesterone)
- digestive enzymes released=sperm penetrates
Where does fertilisation take place?
Fallopian tube
What is the cortical reaction?
Hardening of the zona pellucida to prevent further fertilisation of ovum by more than 1 sperm
-ZP3 receptors on ovum surface degraded=no sperm receptors left
What is the first stage in the development of the conceptus:
Free living phase (9-10 days)
- moving from fallopian tube to uterus
- gets nutrition from uterine secretions
2 stages in implantation:
1) attachment-outer trophoblast cells make contact with uterine endometrium
2) decidualisation-endometrial changes due to progesterone
3 factors involved in implantation:
LIF
IL-11
Progesterone
How do hormones during pregnancy change?
HcG-high until about 40 days (maintains corpus luteum-but then there is the luteo-placental shift)
Oestrogen + progesterone increase throughtout
Lactogen increases
What is the main oestrogen during pregnancy?
Oestriol
What is the purpose of lactogen in pregnancy?
changes metabolism e.g. makes mother more insulin resistance so more glucose to foetus as mother can handle higher glucose levels
What happens to the pituitary gland during pregnancy?
Increases in size due to lactotrophs increasing in size
Why can’t elevated prolactin be used as a test for a prolactinoma if someone is pregnant?
Prolactin levels are increased in pregnancy
3 things oxytocin causes:
Uterine contractions
Cervical dilation
Milk ejection
What is the stimulus for lactation?
Suckling
What can high prolactin levels cause in men + women?
Men=loss of libido
Women=amenorrhoea
What are the 2 hormones req for lactation?
Oxytocin=milk ejection
Prolactin=milk synthesis
