pregnancy parturition and lactation

Question 1

where and when is the delay for fertilization to occur?

Answer 1

days 1-2 after sperm deposited;

at ampullary-isthmic junction

Question 2

when does egg enter uterine cavity?

and as what?

Answer 2

days 3-4

as a morula

Question 3

when does blastocyst implant?

Answer 3

around day 5-7

Question 4

how do steroid hormones circulate?

Answer 4

bound to plasma proteins , they are nonpolar/poorly soluble

little is present in free form –> free form is active/capable of entering target cells

Question 5

what carries estrogen and testosterone in circulation?

what carries cortisol and progesterone?

Answer 5

sex hormone binding globulin (SHBG)

cortisol binding globulin (CBG)

Question 6

binding capacity of cbg and shbg

how is spillover handled?

Answer 6

high affinity but low capacity due to low amounts of cbg and shbg

albumin can carry excess (nonspecific/low affinity but high capacity)

Question 7

blood levels of cbg and shbg are highest in…

Answer 7

pregnant women at term (highest E level)

estrogen stimulates production of both!

Question 8

urinary excretion of free hormone is a direct reflection of what?

Answer 8

index of the levels of ACTIVE free hormone in circulation

Question 9

mechanism of steroid hormone

Answer 9

pass through target cell membrane and bind to cytoplasmic receptor

transfer into nucleus and bind to specific chromatin receptor

RNA transcription –> mRNA –> translation of specific proteins

Question 10

two main chemical modifications to inactivate steroid hormones (in liver)

Answer 10

glucuronidation or sulfation - increases water solubility
reduction - inactivation

allows excretion!

Question 11

3 transport functions of the cervix

Answer 11

• rapid transport of sperm into uterus
• colonization of sperm into cervical crypts
• slow release of sperm from crypts (delayed delivery)

Question 12

how fast do sperm reach fallopian tube? does orgasm play role?

Answer 12

5-15 min!

NO

Question 13

role of sperm motility

Answer 13

necessary for fertilization
but does not account for the rapid transport to the ampulla; it is the female tract fluid movement that mediates this transport

Question 14

sperm capacitation

Answer 14

occurs in the female repro tract and results in a sperm capable of fertilizing an egg

involves the acrosome reaction! –activation of hydrolytic enzymes and the merging of sperm head and membranes

Question 15

acrosome reaction

Answer 15

series of hydrolytic enzyme activation expose proteins on sperm head –>allows a sperm to interact with zona pellucida receptors and digest its way through the egg

Question 16

fertilization is ___ mediated

requires sperm head to bind to ______

Answer 16

receptor;

sperm head must bind to zona pellucida with proteins exposed by acrosome reaction

Question 17

penetration of the vitelline membrane by the sperm requires 2 reactions

Answer 17

1 - release of cortical granules into the perivitelline space (prevents polyspermy)
2-triggers final stages of meiosis in the oocyte (2nd meiotic division, 2nd polar body, and haploid number achieved)

Question 18

the ____ invades the endometrial stroma

Answer 18

syncytiotrophoblast

Question 19

the portion of the blastocyst that lies against the uterine wall is destined to become ____

Answer 19

the fetal placenta (trophoblastic cells)

endometrium at site of contact becomes female placenta (decidua baalis)

Question 20

what transforms the endometrium in contact with blastocyst into the decidua (maternal placenta)?

Answer 20

progesterone from the corpus luteum

no progesterone = no implantation!

Question 21

placenta =

Answer 21

decidua (maternal tissue) + trophoblast

Question 22

autonomy of fetal tissue

Answer 22

after placenta is formed, there is high fetal autonomy in that the trophoblastic tissue produces gonadotropins and steroids that are adequate to maintain gestation,even in complete absence of maternal pituitary and ovarian function

Question 23

hCG

Answer 23

glycoprotein made by the trophoblast

actions are similar to LH

roles: maintain corpus luteum progesterone secretion and stimulation of T secretion by the fetal testis
may also prevent rejection and stimulate placental steroidogenesis

Question 24

earliest sign of definitive pregnancy?

Answer 24

presence of hCG in the plasma (6-8 days after fertilization)

hcg in urine is about 18 days after ovulation

Question 25

HPL

Answer 25

human placental lactogen

resembles prolactin and growth hormone

secreted primarily into MATERNAL circulation
at term it is highest af all placental hormones

roles: metabolization of maternal fat stores, peripheral insulin resistance (allows fat utilization), breast development , and ion transport across amniotic membranes

Question 26

progesterone in pregnancy

Answer 26

progesterone from corpus luteum signals to the hypothalamus that implantation has occured and prevents FSH from initiating follicular phase

it also maintains the vascular bed for implantation (nidation) and quiets the uterus (inhibits formation of prostaglandins and inhibits contractility)

Question 27

after 8 weeks, what is the main source of progesterone?

Answer 27

placenta

Question 28

role of estrogen in pregnancy

Answer 28

1 - uterus growth
2- breast development
3- soften pelvic ligaments
4 - increase steroid carrier proteins
5 - produce clotting factors

Question 29

main source of estrogen in pregnancy

Answer 29

mothers ovaries initially

after 7th week, fetal-placental unit is the primary source of estrogen

Question 30

what 6 effectors induce parturition

Answer 30

1 - progesterone decline
2 - sustained high estrogen (E dominance)
3 - PG formation
4 - upregulated oxytocin receptors
5 - relaxin from placenta and CL
6 - oxytocin by pars nervosa

Question 31

oytocin and delivery

Answer 31

stretching of the uterus and cervix by the baby initiates neuroendocrine reflex for oxytocin release

oxytocin brings increasing rounds of contractions (+ reflex signals for oxytocin release)

Question 32

most effective type of contraception?

Answer 32

oral contraceptives

Question 33

action of estrogen containing birth control pills is to …?

Answer 33

interfere with natural ovarian feedback signal of the follicular phase –> no hypothalamic signal, no ovulatory surge of LH –> no ovulation !

Question 34

DMPA

NET-EN

Answer 34

depot-medroxyprogesterone acetate
norethisterone enantate

long lasting injectable contraceptives (1x every 2-3 months)

Question 35

pre-eclampsia

Answer 35

high BP and proteinuria

symptoms: headaches, visual disturbances, abd. pain, anxiety, and nausea/dizziness

can cause convulsions and coma

Question 36

preeclampsia treatment

Answer 36

only cure is delivery

• use antihypertensives
• use corticosteroids to mature fetal lungs for early delivery