endocrinology of pregnancy

Question 1

semen numbers and how many make it

Answer 1

15-120mil/ml, 1/million make it to ovum

Question 2

formation of seminal fluid

Answer 2

small part from testis, but mainly from ACCESSORY sex glands (prostate, seminal vesicle+ bulbourethral gland)

Question 3

capacitation of sperm

Answer 3

sperm must capacitate to be able to work- this occurs ONLY in female reproductive tract in fallopian tube- glycoprotein coat lost, surface membrane changes and tail develops WHIPLASH movements

Question 4

acrosome reaction DIAGRAM

Answer 4

once capacitation occurs, sperm binds to ZP3 (sperm receptor) on membrane of ovum, Ca2+ influx into sperm occurs, and it penetrates glycoporotein layer surrounding ovum (ZONA PELLUCIDA)

Question 5

fertilisation

Answer 5

in fallopian tube- CORTICAL reaction occurs, where zona pellucida is broken down to prevent further sperm binding: haploid= diploid

Question 6

development of conceptus

Answer 6

keeps dividing as moves down fallopian tube to uterus, receiving nutrients from UTERINE SECRETIONS

Question 7

implantation- 2 phases

Answer 7

attachment phase- uterine contracts due to TROPHOBLAST cells- inolves leukemia inhibitory factor (LIF) and IL11 decidualisation phase uterus lining changes due to progesterone- capillaries growth, secretion from epithelium due to mainly IL11

Question 8

hormone changes during pregnancy DIAGRAM

Answer 8

hCG goes up first- progesterone and oestrogen go up within CORPUS LUTEUM as hCG acts on LH receptors, so hCG goes down after DAY 40 as not needed anymore human placental lactogen also rises

Question 9

progesterone and oestrogen production during pregnancy

Answer 9

maternal and foetal DHEAS is the main source of the oestrogens

Question 10

changes in other hormones during pregnancy

Answer 10

ACTH rises, adrenals, prolactin, IGF1, iodothyronines and PTH gonads (LH/FSH), GH and TSH decrease

Question 11

endocrine control of partruition (labour)

Answer 11

oestrogen, cortisol and oxytocin involved- oxytocin causes uterine contraction, dilation of cervix and milk ejection

Question 12

endocrine control of lactation DIAGRAM

Answer 12

stimulus is suckling, which causes hypothalamus to cause pituitary to release oxytocin (milk EJECTION) and prolactin (milk PRODUCTION)

Question 13

semen formation and voyage

Answer 13

sperm is first concentrated by OESTROGEN, then moves into epididymis, where nutrients are secreted- overall moves form testis to fallopian tube