Placental Hormones

Question 1

Human chorionic gonadotropin (hCG)

Answer 1

• Maintains the corpus luteum of pregnancy
• Stimulates secretion of testosterone by developing testes in XY
  embryos

Question 2

Estrogen

Answer 2

• also secreted by the corpus luteum of pregnancy
• Stimulates growth of the myometrium, increasing uterine
  strength for parturition

Question 3

Progesterone

Answer 3

• Also secreted by corpus luteum of pregnancy
• Suppresses uterine contractions to provide quiet environment
  for the fetus
• Promotes formation of a cervical mucus plug to prevent uterine
  contamination
• Helps prepare the mammary glands for lactation

Question 4

Human chorionic somatomammotropin

Answer 4

• has a structure similar to that of both growth hormone and
  prolactin
• reduces maternal use of glucose and promotes the breakdown of stored fat (similar to growth hormone) so that greater quantities of glucose and free fatty acids may be shunted to the fetus
• Helps prepare the mammary glands for lactation ( similar to
  prolactin)

Question 5

relaxin

Answer 5

• also secreted by the corpus luteum of pregnancy
• Softens the cervix in prep for cervical dilation at parturition
• Loosens the connective tissue between the pelvic bones in prep
  for parturition

Question 6

placental PTHrp

Answer 6

• Parathyroid hormone-related peptide
• Increases maternal plasma Ca2+ level for use in calcifying fetal
  bones
• if necessary, promotes localized dissolution of maternal
  bones, mobilizing their Ca2+ stores for the use by the
  developing fetus

Question 7

Human Chorionic Somatomammotropin

Answer 7

• Humanchorionic somatomammotropin (hCS) is also called
  human placental lactogen (hPL).
• Initially believed to be necessary for breast development during
  pregnancy and for milk production (lactation).
• Women who do not make hCS during pregnancy because of a
  genetic defect still have adequate breast development and milk
  production.
• Alteration of the mother’s glucose and fatty acid metabolism to
  support fetal growth (glucose resistance)
  > in the late stages of pregnancy, the foetus often uses as much
  glucose as the entire body of the mother uses
• During pregnancy, about 4% of women develop gestational
  diabetes mellitus (GDM), with elevated blood glucose levels
  caused by insulin resistance, similar to type 2 diabetes.

Question 8

Question 9

Parturition

Answer 9

• During the first 2 trimesters the uterus is quiet
• In third trimester uterus become more exitable and leads to
  Braxton-Hicks false contractions
• As parturition approaches cervix softens due to dissociation of
  collagen fibers
  > Relaxin produced by CL of pregnancy and placenta
  > Relaxin also softens connective tissue between pelvic bones

Question 10

Question 11

Question 12

Lactation – The mammary gland

Answer 12

lobes (15- 20) divided by adipose tissue – has nothing to do with ability to nurse
lobules contain glandular alveoli secrete milk in lactating female
milk is secreted into a series of secondary tubules
tubules converge to form a series of mammary ducts
converge to form a lactiferous duct – drains into tip of nipple
lumen expands to form an ampulla (milk accumulation)
high estrogen and progesterone prevent lactation before parturition
loss of placenta abruptly declines estrogen and prolactin levels and initiates lactation

Question 13

Question 14

Lactation – The suckling reflex

Answer 14

Question 15

Breast milk benefits to infant

Answer 15

Question 16

Breast milk benefits to mother

Answer 16

Question 17

Menopause

Answer 17

• All women undergo menopause
• decrease in estrogen due to follicle depletion
• decrease of estrogen = risk of osteoporosis
• around the age of 50
• 60 onwards = postmenopause

Question 18

andropause

Answer 18

• Only some men undergo andropause
• Decrease in testosterone due to
  > Hypothalamus decreasing testosterone inhibition
  > Circadian rhythm dysfunction
  > Testicular defect (Leidig cells)
• Decrease of testosterone = risk of osteoporosis