NM704 Exam - Questions With Verified Solutions
(100%)
Placental events that cause labor (2 points) Right Ans - 1. Placental
production of corticotropin-releasing hormone (CRH) increases over the
course of pregnancy and peaks at the time of birth
2. Researchers call this the "placental clock" as the inciting mechanism for
labor
Corticotropin-releasing hormone (CRH)'s role in starting labor (5 points)
Right Ans - 1. From placenta and fetus
2. Facilitates maturation of the fetal HPA axis, which initiates production of
cortisol and estrogenprecursors from the fetal adrenal gland
3. Enhances uterine response to oxytocin and prostaglandins
4. Promotes pro-inflammatory response (production of cytokines)
5. The type of CRH receptors present in the uterine myometrium shifts from
those that suppress uterine contractions to those that promote contractile
activity.
The role of fetal hormones in starting labor (4 points) Right Ans - 1. In
response to placental CRH, the fetal hypothalamic-pituitary-adrenal (HPA)
axis stimulates the fetal adrenal gland to synthesize and excrete the chemical
precursor the placenta must have to synthesize estrogen.
2. The resultant placental synthesis of estrogen increases such that more
estrogen than progesterone is available.
1. Estrogen then initiates multiple changes in the uterine myometrium that
facilitates myometrial contraction.
2. The fetal adrenal gland also produces cortisol, which stimulates placental
CRH production
The maternal components in starting labor (3 points) Right Ans - 1.
Cervical Remodeling (softening, ripening, dilation, and repair)
2. Prelabor Uterine Contractions
3. Environmental influences, stress, and healthcare interventions
Describe the anatomic and physiologic changes in the cervix necessary for the
onset and progress of labor
Cervical remodeling (4 Phases) Right Ans - 1. Softening
,2. Ripening
a. Occurs just prior to labor and/or during the first hours of labor.
b. It changes from being relatively firm and measuring approx. 3-4 cm in
length, to being much softer and shorter.
c. The process of thinning, referred to as cervical effacement, can be measured
when the cervix is palpated clinically.
d. Effacement is evaluated in terms of cervical length in cm or by reporting a
percentage of the original length
3. Dilation
a. The opening and widening of the cervical OS.
4. Repair
What are the inhibitors seen in Phase 0 of Parturition, Quiescence? (5)
Right Ans - 1. Progesterone
2. Prostacyclin
3. Relaxin
4. Nitric oxide
5. CRH
What are the uterotropins in Phase 1 of Parturition, Activation? (2) Right
Ans - 1. Estrogen
2. Prostaglandins
What are the uterotonins in Phase 2 of Parturition, Stimulation? (2) Right
Ans - 1. Prostaglandins
2. Oxytocin
Describe the significance of progesterone in the onset of and progress of labor
(6 points) Right Ans - 1. Progesterone levels do not fall in labor
2. But its actions on the myometrium change prior to labor
3. Progesterone is synthesized in the placenta.
4. The uterus different progesterone receptors that have different functions.
5. During pregnancy
a. progesterone primarily binds to PR-B
b. which suppresses contractions
c. blocks upregulation of prostaglandin and oxytocin receptors that initiate
contractions
, 6. During labor
a. the myometrium PR-A
b. When progesterone binds to PR-A it causes pro-inflammatory effects
associated with labor
c. There is no change in circulation progesterone concentrations
d. But the change in receptor concentrations changes the effects of
progesterone
Describe the significance of estrogen in the onset of and progress of labor
Estrogen has four main actions (4) Right Ans - 1. Causes the inflammatory
cascades
2. Myometrial cells to express receptors for prostaglandins and oxytocin
3. Gap junctions -allows communication between muscle cells to start
contractions
Note: estrogen does not cause the myometrium to become contractile but it
promotes cellular changes that support coordination of the contractions
Describe the significance of prostaglandins in the onset of and progress of
labor (5 points) Right Ans - Come from the fetal membrane
Prostaglandins have 4 main actions:
1. Promote cervical ripening
2. Increase myometrial sensitivity to oxytocin
3. Promote formation of gap junctions
4. Cause an upregulation of oxytocin receptors
Describe the significance of oxytocin in the onset of and progress of labor (4
points) Right Ans - Source: hypothalamus, fetus, fetal membrane, placenta
Oxytocin has
1. Increases prostaglandin production
2. Induce myometrial contractions when bound to oxy receptors (releasing
intracellular calcium)
3. Potent UTEROTONIC
NO, the two do not correlate
Uterine contractility has more to do with the number of oxytocin receptors
and their sensitivity
(100%)
Placental events that cause labor (2 points) Right Ans - 1. Placental
production of corticotropin-releasing hormone (CRH) increases over the
course of pregnancy and peaks at the time of birth
2. Researchers call this the "placental clock" as the inciting mechanism for
labor
Corticotropin-releasing hormone (CRH)'s role in starting labor (5 points)
Right Ans - 1. From placenta and fetus
2. Facilitates maturation of the fetal HPA axis, which initiates production of
cortisol and estrogenprecursors from the fetal adrenal gland
3. Enhances uterine response to oxytocin and prostaglandins
4. Promotes pro-inflammatory response (production of cytokines)
5. The type of CRH receptors present in the uterine myometrium shifts from
those that suppress uterine contractions to those that promote contractile
activity.
The role of fetal hormones in starting labor (4 points) Right Ans - 1. In
response to placental CRH, the fetal hypothalamic-pituitary-adrenal (HPA)
axis stimulates the fetal adrenal gland to synthesize and excrete the chemical
precursor the placenta must have to synthesize estrogen.
2. The resultant placental synthesis of estrogen increases such that more
estrogen than progesterone is available.
1. Estrogen then initiates multiple changes in the uterine myometrium that
facilitates myometrial contraction.
2. The fetal adrenal gland also produces cortisol, which stimulates placental
CRH production
The maternal components in starting labor (3 points) Right Ans - 1.
Cervical Remodeling (softening, ripening, dilation, and repair)
2. Prelabor Uterine Contractions
3. Environmental influences, stress, and healthcare interventions
Describe the anatomic and physiologic changes in the cervix necessary for the
onset and progress of labor
Cervical remodeling (4 Phases) Right Ans - 1. Softening
,2. Ripening
a. Occurs just prior to labor and/or during the first hours of labor.
b. It changes from being relatively firm and measuring approx. 3-4 cm in
length, to being much softer and shorter.
c. The process of thinning, referred to as cervical effacement, can be measured
when the cervix is palpated clinically.
d. Effacement is evaluated in terms of cervical length in cm or by reporting a
percentage of the original length
3. Dilation
a. The opening and widening of the cervical OS.
4. Repair
What are the inhibitors seen in Phase 0 of Parturition, Quiescence? (5)
Right Ans - 1. Progesterone
2. Prostacyclin
3. Relaxin
4. Nitric oxide
5. CRH
What are the uterotropins in Phase 1 of Parturition, Activation? (2) Right
Ans - 1. Estrogen
2. Prostaglandins
What are the uterotonins in Phase 2 of Parturition, Stimulation? (2) Right
Ans - 1. Prostaglandins
2. Oxytocin
Describe the significance of progesterone in the onset of and progress of labor
(6 points) Right Ans - 1. Progesterone levels do not fall in labor
2. But its actions on the myometrium change prior to labor
3. Progesterone is synthesized in the placenta.
4. The uterus different progesterone receptors that have different functions.
5. During pregnancy
a. progesterone primarily binds to PR-B
b. which suppresses contractions
c. blocks upregulation of prostaglandin and oxytocin receptors that initiate
contractions
, 6. During labor
a. the myometrium PR-A
b. When progesterone binds to PR-A it causes pro-inflammatory effects
associated with labor
c. There is no change in circulation progesterone concentrations
d. But the change in receptor concentrations changes the effects of
progesterone
Describe the significance of estrogen in the onset of and progress of labor
Estrogen has four main actions (4) Right Ans - 1. Causes the inflammatory
cascades
2. Myometrial cells to express receptors for prostaglandins and oxytocin
3. Gap junctions -allows communication between muscle cells to start
contractions
Note: estrogen does not cause the myometrium to become contractile but it
promotes cellular changes that support coordination of the contractions
Describe the significance of prostaglandins in the onset of and progress of
labor (5 points) Right Ans - Come from the fetal membrane
Prostaglandins have 4 main actions:
1. Promote cervical ripening
2. Increase myometrial sensitivity to oxytocin
3. Promote formation of gap junctions
4. Cause an upregulation of oxytocin receptors
Describe the significance of oxytocin in the onset of and progress of labor (4
points) Right Ans - Source: hypothalamus, fetus, fetal membrane, placenta
Oxytocin has
1. Increases prostaglandin production
2. Induce myometrial contractions when bound to oxy receptors (releasing
intracellular calcium)
3. Potent UTEROTONIC
NO, the two do not correlate
Uterine contractility has more to do with the number of oxytocin receptors
and their sensitivity
