Physio Of Pregnancy, Parturition, Lactation

Question 1

what is the mature placenta composed of?

Answer 1

chorionic villi, intervillous space, decidua basalis

Question 2

Umbilical vein carries what?

what about the arteries?

Answer 2

O2 rich blood

O2 poor blood

Question 3

spiral arteries from the mother dump where?

Answer 3

into the intervillous space

Question 4

what is the placenta the lifeline for for the fetus?

Answer 4

Fetal Gut, lung, and kidney

Question 5

what is the intervillous space also called?

why is this?

Answer 5

functional capillary

because there’s no capillaries present between the maternal arterioles and venules

Question 6

factors regulating maternal blood flow?

Answer 6

maternal arterial blood pressure, intra-uterine pressure, pattern of uterine contraction.

Question 7

the fetus has high affinity for what?

Answer 7

O2

so the hemoglobin of the fetus is higher so it helps facilitate the O2 blood from the mom to the fetus

this happens regardless of the intervillous space having low PO2 from the maternal blood.

Question 8

other than fetal Hb, what else ensures adequate fetal oxygenation?

Answer 8

high cardiac output to increase the carrying capacity

Question 9

what crosses the placenta?

Answer 9

waste (urea and creatinine)

lipid soluble steroid hormones

glucose

Question 10

Endocrine function of the placenta?

Answer 10

syncytiotrophoblasts of the placenta produce several steroid and protein hormones.

**maintain pregnant state of the uterus –> hCG

**stimulation of alveolar growth and maternal breasts

**maternal metabolism

**regulation of development and partuition

Question 11

first hormone released by syncytiotrophoblasts? when is it highest?

Answer 11

hCG.. the beta subunit is an indication of pregnancy so this is why pregnancy tests work. 10 weeks is highest amount.

Question 12

when hCG is reduced, what increases?

Answer 12

progesterone from the placenta because we have a shift from having the corpus luteum producing progesterone to the actual placenta producing it… key to maintaining pregnancy

Starts at week 10

Question 13

Human placental lactose?

Answer 13

Growth Hormone

Question 14

What are the levels of estrogen in the placenta?

Answer 14

Estradiol is highest, then estriol, then estrone.

in estriol, we have higher levels of this during pregnancy.. outside of pregnancy is estradiol.

Question 15

hCG has a high affinity for what?

Answer 15

the LH receptor to stimulate it on the corpus luteum to maintain progesterone levels.

Question 16

Human Placental Lactogen (hPL)

produced by what?

similar to what?

what actions does it have on the body like growth hormone?

Answer 16

produced by syncytiotrophoblast

similar structure to prolactin

**antagonistic action to insulin, contributing to the diabetogenicity of pregnancy*

so it’s like Growth hormone!!

helps shift lipids to the baby for energy

Question 17

Progesterone?

what produces it for this lecture and what is it required to do?

regulation?

Answer 17

placenta produces a high amount of progesterone, which is required to maintain a quiescent myometrium and a pregnant uterus.

the placenta produces as much progesterone as the cholesterol levels and the levels of desmolase / 3B-HSD will allow.

Question 18

Estrogen produced by syncytiotrophoblasts?

what comes from the fetus?

major estrogen of pregnancy?

Answer 18

aromatase in the placenta (from syncytiotrophoblasts) facilitates the production of estradiol, estrone, and estrione from the DHEAS (sulforated?) released from the fetal zone.

Estriol

Question 19

Estrogen

Answer 19

increasing utter-placental blood flow

increase LDL expression in the syncytiotrophoblasts because it needs to sequester cholesterol from the mom to make more estrogenic activities.

induce prostaglandins and oxytocin for parturition

growth and development of breasts

Question 20

what do syncytiotrophoblasts have that creates a ton of progesterone?

what protein is not required although it’s required by other cells?

Answer 20

a lot of CYP11a and 3B-HSD

StAR protein

also blocks CYP17… which is 17a hydroxylase and the 17,20 desmolase… so it doesn’t go to testosterone

Question 21

what happens in very late pregnancy to develop the adrenal cortex?

how do we avoid high levels of cortisol in the fetus but

Answer 21

fetal pituitary release ACTH which acts on cholesterol… this portion of the fetus DOES HAVE 17a hydroxylase/17,20 desmolase so it goes to Cortisol

Question 22

cortisol to cortisone?

Answer 22

11B-HSD type 2

protects fetal adrenal axiss from maternal cortisol

Question 23

Progesterone does what for uterine motilityy? what about contractions?

Answer 23

REDUCES AND INHIBITS

Question 24

MAIN estrogen subtype of pregnancy?

Answer 24

ESTRIOL

Question 25

what does the maternal placental-fetal unit do to overcome the placental limitations?

Answer 25

mother supplies cholesterol as LDL

fetal adrenal glands and liver supply the enzymes lacking in the placenta.

Question 26

fetus shouldn’t be making any estrogens why

Answer 26

if it did, it would expose itself to high levels of hormones that are needed by the mother, not the fetus.

so no 3B-HSD and aromatase.

Question 27

what does the fetus do with sulfate?

what does this include?

Answer 27

conjugates stuff to reduce its activity

pregnenalone

DHEA

Question 28

Progesterone and alveolar ventilation?

Answer 28

increases it

Question 29

what promotes quiet uterus activity?

Answer 29

progesterone and relaxin

Question 30

what happens during labor for the myometrium?

Answer 30

increase in gap junctions between myometrial cells and increase the # of oxytocin receptors

Question 31

0 station?

Answer 31

when the baby’s head is even with ischial spines

Question 32

what increases the uterine contractility?

what does this do?

Answer 32

estrogen….

technically both estrogen and progesterone increase during pregnancy but estrogen increases even more and progesterone remains constant from 7 month on.

increases oxytocin receptors

Question 33

what initiales labor?

what physical thing of the uterus increases these?

Answer 33

prostaglandins –> PGF2a and PGE 2 increase motility of the uterus

stretch of the uterus

Question 34

Ferguson reflex?

Answer 34

stretch of the cervix

Question 35

what initiates labor?

then once labor is released, what’s released in bursts and what does it do?

Answer 35

prostaglandins

oxytocin, stimulates powerful contractions to sustain labor.

Question 36

Relaxin does what?

Answer 36

produced by corpus luteum, placenta, and decidua

keeps uterus quiescent during pregnancy

Question 37

Braxton Hicks contractions?

Answer 37

weak and slow rhythmic contractions throughout pregnancy but they get super strong

Question 38

preeclampsia?

Answer 38

high blood pressure and signs of damage to another organ system –> often the kidneys

Question 39

why doesn’t prolactin act and help make milk during pregnancy?

Answer 39

it’s inhibited by high estrogen and progesterone

Question 40

lactation initiation?

Answer 40

prolactin up

estrogen and progesterone down

suckling

Question 41

four effects of suckling on hormone release?

Answer 41

1) seeing or hearing the kid suck
2) dopamine release is inhibited (remember that is PIF)
3) spinal cord neurons stimulate the production and release of oxytocin from posterior pituitary
4) spinal cord neurons inhibit the arcuate and prep-tic area of hypothalamus causing fall in GnRH production

Question 42

suckling reduces GnRH production.. so what’s going to be inhibited?

Answer 42

LH and FSH so inhibiting the ovarian cycle