Physio: Parturition

Question 1

Which of the following is NOT listed as a key outcome of the regular, rhythmic, forceful, and painful contractions during parturition?
a) Progressive cervical dilatation
b) Fetus descent
c) Expulsion of fetus
d) Development of fetal surfactant

Answer 1

d) Development of fetal surfactant

Question 2

Which of the following is listed as a factor that initiates labor?
a) Maternal nutrition
b) Fetal sleep cycles
c) Mechanical factors (stretch of the uterus)
d) Genetic predisposition

Answer 2

c) Mechanical factors (stretch of the uterus)

Hormonal factors and inflammation of the uterus.

Question 3

Hormonal changes initiating labor include a sharp rise in the plasma ratio of which hormones towards the end of gestation?
a) Progesterone-to-estrogen
b) Oxytocin-to-progesterone
c) Estrogen-to-progesterone
d) Relaxin-to-oxytocin

Answer 3

c) Estrogen-to-progesterone

Question 4

Which hormone is described as promoting uterine contractions and serving as a prolabor hormone?
a) Progesterone
b) Oxytocin
c) Estrogen
d) Cortisol

Answer 4

c) Estrogen

Question 5

Which hormone is described as promoting uterine relaxation and serving as a progestation hormone?
a) Estrogen
b) Oxytocin
c) Cortisol
d) Progesterone

Answer 5

d) Progesterone

Question 6

By the end of pregnancy, which hormone’s plasma levels continue to rise, while the other reaches a plateau?
a) Progesterone continues to rise, while Estrogen plateaus
b) Oxytocin continues to rise, while Progesterone plateaus
c) Estrogen continues to rise, while Progesterone plateaus
d) Cortisol continues to rise, while Estrogen plateaus

Answer 6

c) Estrogen continues to rise, while Progesterone plateaus

Question 7

During pregnancy, where are estrogens primarily produced?
a) Maternal ovaries
b) Fetal liver
c) Placenta
d) Maternal adrenal cortex

Answer 7

c) Placenta

Question 8

The immediate precursor for estrogen synthesis by the placenta is what?
a) Cholesterol
b) Pregnenolone
c) DHEA (androgen)
d) Cortisol

Answer 8

c) DHEA (androgen)

Question 9

The precursor for steroid hormones produced by the placenta, which it cannot synthesize itself and is supplied from the mother’s circulation, is what?
a) DHEA
b) Pregnenolone
c) Cholesterol
d) Cortisol

Answer 9

c) Cholesterol

Question 10

From the placenta, cholesterol goes to the fetal circulation and is converted to DHEA in which fetal organ?
a) Fetal liver
b) Fetal pituitary
c) Fetal adrenal cortex
d) Fetal hypothalamus

Answer 10

c) Fetal adrenal cortex

Once cholesterol enters the fetal circulation from the mother, the fetus adrenal cortex takes the cholesterol > DHEA > DHEA is transported to the placenta > Conversion to estrogen

Question 11

What hormone secreted by the fetal hypothalamus and placenta triggers the elevation of maternal plasma estrogens at the end of term?
a) ACTH
b) Cortisol
c) Corticotropin-releasing hormone (CRH)
d) Oxytocin

Answer 11

c) Corticotropin-releasing hormone (CRH)

Question 12

CRH from the fetal hypothalamus and placenta increases the secretion of which hormone in the anterior pituitary?
a) Cortisol
b) DHEA
c) Estrogen
d) ACTH

Answer 12

d) ACTH

Question 13

ACTH in the fetal anterior pituitary increases the secretion of which hormones from the fetal adrenal cortex?
a) Estrogens
b) Progesterone
c) Androgens (like DHEA)
d) CRH

Answer 13

c) Androgens (like DHEA)

Question 14

How does the placenta contribute to the increase in maternal plasma estrogens at the end of gestation, after receiving a precursor from the fetus?

a) It synthesizes cholesterol from maternal circulation
b) It converts pregnenolone to progesterone
c) It converts androgens (like DHEA) to estrogens
d) It directly secretes CRH into maternal circulation

Answer 14

c) It converts androgens (like DHEA) to estrogens

Question 15

According to the “fetal stress” theory, why is CRH secretion increased by the end of term?

a) The placenta becomes less efficient at producing progesterone.
b) Fetal lungs are maturing and releasing surfactant.
c) Maternal immune response is suppressed.
d) The large fetus outstrips the placenta’s ability to supply oxygen/nutrients and remove waste.

Answer 15

d) The large fetus outstrips the placenta’s ability to supply oxygen/nutrients and remove waste.

Due to this the mismatch response causes metabolic stress which triggers the fetal hypothalamus and placenta to excrete CRH > AP > ACTH > Adrenal cortex> Cortisol

Question 16

According to the “placental clock” theory, what determines the timing for increasing CRH secretion and hence the timing for labor?

a) Maternal nutritional status throughout pregnancy.
b) The placenta itself, establishing the timing early in pregnancy.
c) The degree of uterine stretch.
d) Fetal stress hormones reaching a critical level.

Answer 16

b) The placenta itself, establishing the timing early in pregnancy.

The placenta determines when CRH secretion and the timing for labor. The time is established during early pregnancy and the clock ticks until the end of pregnancy marking the end of the gestation

Question 17

Which of the following summarizes why maternal plasma estrogens are increased by the end of gestation, according to the source?

a) Increased production of progesterone by the corpus luteum.
b) Increased secretion of relaxin by the ovaries.
c) Increased availability of DHEA due to ACTH stimulation by CRH, converted to estrogens by the placenta.
d) Direct synthesis of estrogens by the fetal adrenal cortex.

Answer 17

c) Increased availability of DHEA due to ACTH stimulation by CRH, converted to estrogens by the placenta.

Question 18

Where is progesterone initially supplied during pregnancy, before the placenta takes over for the later two-thirds?

a) Fetal adrenal cortex
b) Maternal adrenal cortex
c) Corpus luteum in the ovary
d) Uterine decidua

Answer 18

c) Corpus luteum in the ovary

Question 19

Maternal plasma progesterone levels stop increasing from which month of pregnancy onwards?
a) 4th month
b) 5th month
c) 6th month
d) 7th month

Answer 19

d) 7th month

Question 20

The source states that increased secretion of cortisol by the fetus’ adrenal cortex at the end of pregnancy contributes to offsetting the production of which hormone?

a) Estrogen
b) Oxytocin
c) Relaxin
d) Progesterone

Answer 20

d) Progesterone

Question 21

In the fetal adrenal cortex, ACTH stimulates the secretion of androgens (like DHEA) and also which other hormone that plays a role in limiting progesterone production?

a) Estrogen
b) Oxytocin
c) Relaxin
d) Cortisol

Answer 21

d) Cortisol

Question 22

High levels of cortisol in the blood inhibit the synthesis of progesterone in which organs, according to the source?

a) Fetal adrenal cortex and fetal pituitary
b) Maternal hypothalamus and maternal pituitary
c) Ovaries and placenta
d) Uterine muscle and cervix

Answer 22

c) Ovaries and placenta

Question 23

Besides its role in influencing progesterone production, Cortisol also stimulates the maturation of fetal lungs by increasing the production of what substance?
a) Collagen
b) Prostaglandins
c) Oxytocin
d) Surfactant

Answer 23

d) Surfactant

Question 24

The summary diagram in the source indicates that Cortisol from the fetal adrenal cortex has what effect on Progesterone production?

a) Stimulates it (+)
b) Has no direct effect
c) Inhibits it (-)
d) Converts it to Estrogen

Answer 24

c) Inhibits it (-)

Question 25

Cortisol stimulates the secretion of which hormone, creating a positive feedback loop involving the pituitary and adrenal cortex? a) ACTH b) DHEA c) Estrogens d) CRH

Answer 25

d) CRH

Question 26

Prostaglandins E2 and F2alpha are a family of paracrine agents synthesized in the placenta that have what primary effect on the uterus? a) Promote uterine relaxation b) Inhibit uterine contractions c) Strongly stimulate contractions of the uterine smooth muscle d) Inhibit formation of gap junctions

Answer 26

c) Strongly stimulate contractions of the uterine smooth muscle Note: Cortisol stimulates the production of prostaglandins and CRH

Question 27

Prostaglandins promote the formation of gap junctions between uterine smooth muscle cells by increasing the synthesis of what? a) Collagen b) Elastin c) Myosin d) Connexons

Answer 27

d) Connexons

Question 28

Promoting the formation of gap junctions by increasing connexon synthesis allows for what effect on uterine contractions? a) Weakens contractions b) Makes contractions irregular c) Permits synchronous contractions d) Inhibits contractions

Answer 28

c) Permits synchronous contractions

Question 29

Besides stimulating uterine contractions, prostaglandins also have what important effect on the uterine cervix before labor? a) Cause hardening and thickening b) Inhibit ripening c) Cause softening, dilatation, and thinning d) Increase collagen content

Answer 29

c) Cause softening, dilatation, and thinning

Question 30

What class of drugs, which inhibits cyclooxygenase (COX), is mentioned as reducing prostaglandin formation and potentially inhibiting labor? a) Opioid analgesics b) Steroidal anti-inflammatories c) Antibiotics d) Non-steroid anti-inflammatory drugs (like Aspirin)

Answer 30

d) Non-steroid anti-inflammatory drugs (like Aspirin)

Question 31

Initiation of labor is summarized as being caused by progesterone withdrawal along with increased effects of estrogens, oxytocin, and which other substance? a) Relaxin b) Cortisol c) DHEA d) Prostaglandins

Answer 31

d) Prostaglandins

Question 32

Which mechanical factor is highlighted as potentially initiating rhythmic uterine contractions at the start of labor? a) Maternal movement b) Fetal heart rate c) Placental blood flow d) Mechanical stretch placed on the uterine muscle

Answer 32

d) Mechanical stretch placed on the uterine muscle

Question 33

The fact that twins are born earlier than a single child, on average, is emphasized in the source to highlight the importance of what factor in initiating uterine contractions? a) Hormonal changes b) Uterine inflammation c) Maternal age d) Mechanical stretch

Answer 33

d) Mechanical stretch The size of a fetus and the increase movements of a fetus are mechanical factors that initiate labor

Question 34

Cervical stretch is particularly important during labor as it initiates contractions of the uterine body via what mechanism? a) A hormonal feedback loop involving oxytocin. b) Release of prostaglandins from the cervix. c) Activation of uterine inflammation. d) Reflex feedback loop

Answer 34

d) Reflex feedback loop

Question 35

Apart from uterine stretch, what other mechanical factor is mentioned as playing a role in active labor through contraction? a) Diaphragmatic muscle contraction b) Perineal muscle relaxation c) Contraction of abdominal muscles d) Involuntary leg movements

Answer 35

c) Contraction of abdominal muscles

Question 36

Pain signals from the uterus and birth canal during strong uterine contractions elicit neurogenic reflexes in the spinal cord that cause intense contractions of which muscles? a) Diaphragm b) Pelvic floor muscles c) Back muscles d) Abdominal muscles

Answer 36

d) Abdominal muscles

Question 37

Uterine inflammation is listed as a factor that can initiate labor, particularly through the activation of which key nuclear factor? a) AP-1 b) STAT3 c) NF-kB (nuclear factor kB) d) PPARgamma

Answer 37

c) NF-kB (nuclear factor kB)

Question 38

Activation of NF-kB in the uterine muscle is caused by stretching the uterine muscle and by the action of what substance released from the fetal lungs into the amniotic fluid? a) Cortisol b) DHEA c) Interleukin-1beta d) Pulmonary surfactant protein SP-A

Answer 38

d) Pulmonary surfactant protein SP-A

Question 39

SP-A promotes the migration of which type of cells to the uterus, which then produce inflammatory cytokines? a) Neutrophils b) Lymphocytes c) Mast cells d) Fetal macrophages

Answer 39

d) Fetal macrophages

Question 40

Fetal macrophages migrating to the uterus in response to SP-A produce which inflammatory cytokine that activates NF-kB? a) Tumor Necrosis Factor-alpha (TNF-alpha) b) Interleukin-6 (IL-6) c) Interleukin-8 (IL-8) d) Interleukin-1beta (IL-1beta)

Answer 40

d) Interleukin-1beta (IL-1beta) Once NF- kB is activated it promotes the stimulation of prostaglandins and Interleukin-1beta that promotes labor

Question 41

Bacterial infections and allergic reactions are mentioned as potential activators of NF-kB, which can lead to what outcome? a) Post-term delivery b) Increased placental function c) Delayed labor d) Premature labor

Answer 41

d) Premature labor

Question 42

Once activated, NF-kB stimulates the production of cytokines (like interleukin 8) and prostaglandins, which have what overall effect? a) Inhibit labor b) Have no effect on labor c) Delay the start of labor d) Promote the labor

Answer 42

d) Promote the labor Mature lungs in fetus also can activate labor

Question 43

The first stage of active labor is primarily characterized by what process? a) Expulsion of the fetus b) Expulsion of the placenta c) Contraction of abdominal muscles d) Cervical dilation

Answer 43

d) Cervical dilation Uterine contractions Rupture of Amniotic sac Dilation of cervix

Question 44

The first sign that signals to the mother that labor is imminent, according to the source, is typically what event? a) Onset of painful contractions b) Feeling the urge to push C) Seeing the fetal head crowning d) Rupture of the amniotic sac

Answer 44

d) Rupture of the amniotic sac

Question 45

The postpartum period, where maternal reproductive organs return to the pre-pregnancy state, is called what? a) Gestation b) Parturition c) Menstruation d) Puerperium

Answer 45

d) Puerperium

Question 46

Involution of the uterus is the process of its size reduction postpartum. This process is described as being facilitated by which hormone, released in response to suckling during breastfeeding? a) Estrogen b) Progesterone c) Relaxin d) Oxytocin

Answer 46

d) Oxytocin

Question 47

After delivery (2-4weeks) females pass out which substance? What is its components?

Answer 47

Lochia Lochia comprises of disintergrated and sloughed off epithelial cells that were not removed during labor. It is made up of blood > then serious fluid

Question 48

Postpartum stimulates which 3 factors that decrease the size of the uterus?

Answer 48

Uterine catabolism Decrease blood flow Vasculature regression

Question 49

Expulsion of the fetus, Stage 2 of Partiuiration, involves which events?

Answer 49

1. Amniotic sac ruptures > amniotic fluid drains 2. Fetus pushes head down and acts as a wedge to open structures of the birth canal 3. Fetus is expelled and umbilical cord is cut and severed.

Question 50

What happens to estrogen of progesterone levels during postpartum?

Answer 50

The levels drop due to the absence of the placenta as a source to supply.