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Reproductive And Development > 2-25&26-16-Physiology Of Pregnancy, PARTURITION And LACTATION (Lopez)-Covers Slide 49-82 > Flashcards

2-25&26-16-Physiology Of Pregnancy, PARTURITION And LACTATION (Lopez)-Covers Slide 49-82 Flashcards

1
Q

___ is a series of regular, rhythmic, and forceful contractions that develops to facilitate thinning and dilation of the cervix

A

Obstetric definition of labor

-Contractions may last for several hours, a day, or even longer and may eventually result in expulsion of the fetus, placenta, and membranes

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2
Q

This stage of labor is defined by uterine tranquility and refractoriness to contraction

A

0

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3
Q

This stage of labor is defined by uterine awakening, initiation of parturition, extending to complete cervical dilatation

A

1

-Increase in the number of gap junctions between myometrial cells; increase in number of oxytocin receptors

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4
Q

This stage of labor is defined by active labor, from complete cervical dilatation to delivery of the newborn

A

2

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5
Q

This stage of labor is defined by “from delivery of the fetus to expulsion of the placenta and final uterine contraction

A

3

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6
Q

THere are signals from the placenta and fetus that may initiate labor:

The placenta produces ____ and maternal serum levels of this hormone increase rapidly during late pregnancy and labor

A

CRH

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7
Q

As placental CRH accumulates in the fetal circulation during labor, it stimulates fetal ___ secretion, which stimulates both fetal adrenal cortisol and fetoplacental estrogen production

A

ACTH

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8
Q

In contrast to the inhibitory effect of cortisol on hypothalamic CRH production, ___ stimulates placental CRH production (self-amplifying positive feedback loop)

A

Cortisol

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9
Q

__ promotes contractions by sensitizing the uterus to prostaglandins and oxytocin. Estrogen also stimulates contractions

A

CRH

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10
Q

Toward the end of pregnancy, the uterus becomes progressively more ___, until finally it develops such strong rhythmical contractions that the baby is expelled

These 2 major categories of effects lead up to the intense contractions:

A

Excitable

Progressive hormone changes and Progressive mechanical changes

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11
Q

___ hormones increases the degree of uterine contractility. From the 7th month, secretion of this hormone continues to increase while progesterone remains constant. It also stimulates synthesis of oxytocin receptors

A

Estrogen

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12
Q

___ are believed to initiate labor. It synthesis is stimulated by estrogen from arachidonic acid in fetal membrane and by oxytocin in uterine cells. The amount of this compound increases during parturition and plays a role in enhancing motility/contraction of uterine smooth muscle cells

A

Prostaglandins

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13
Q

These prostaglandins increase uterine motility and large doses of these can be used to induce labor

A

PGF2alpha and PGE2

Levels of PG’s increase in uterus, placenta, amniotic fluid, fetal membranes before onset of labor

Uterine stretch stimulates uterine PG production

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14
Q

Estrogen increases the number of ___ receptors in the myometrial and decidual tissue of pregnant women.

A

Oxytocin

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15
Q

The uterus remains insensitive to oxytocin until about __ weeks of gestation, at which time the number of oxytocin receptors increases to 80x higher than baseline values by about ___ weeks of gestation, it will plateau just before labor, then rise again to 200x during early labor

A

20

36

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16
Q

The uterus is sensitive to ___ only at the end of pregnancy, whereas it is susceptible to __ throughout pregnancy

A

Oxytocin

PG’s

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17
Q

When oxytocin is released in response to cervical stretch, it is known as the ___ reflex

A

Ferguson–> stimulates uterine contractions, thereby facilitating labor

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18
Q

While oxytocin and PG’s play an important role in stimulating uterine contractions, only ___ are believed to have a key role in the initiation of labor

A

PGs

Once labor is initiated (stage 1), maternal oxytcin is released in bursts and the frequency of these bursts increases as labor progresses

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19
Q

Oxytocin binds receptors on decidual cells, thereby stimulating ___ production

A

PGF2alpha

During 2nd stage of labor, oxytocin release may play a synergistic role in the expulsion of the fetus by virtue of its ability to stimulate PG release

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20
Q

___ causes the uterus to contract immediately after the fetus is expelled, limiting blood flow and blood loss

A

Oxytocin

During 3rd stage of labor, uterine contractions induced by oxytocin are important for constricting uterine blood vessels at the site where the placenta used to be, thus promoting blood coagulation

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21
Q

___ is a protein produced by the corpus luteum, placenta, and decidua that keeps the uterus quiescent during pregnancy. Production and release of this hormone factor increases during labor and may soften and dilate cervix during labor

A

Relaxin

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22
Q

The fetal ___ secretes increasing quantities of oxytocin, which might play a role in exciting the uterus

The fetal ___ secretes large quantities of cortisol, which could also be a uterine stimulant

The fetal ___ release PG’s in high concentration at the time of labor and increases the intensity of uterine contractions

A

Pituitary

Adrenals

Placental membranes

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23
Q

When are twins typically born compared to a single child?

A

Twins are born, on average, 19 days earlier than a single child, which emphasizes the importance of mechanical stretch in starting uterine contraction

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24
Q

Most of the pregnancy, the uterus undergoes periodic episodes of weak and slow rhythmic contractions called ___ which become exceptionally strong during the last hours of the pregnancy

A

Braxton-hicks contractions

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25
Q

When contractions start stretching the cervix and later force the baby through the birth canal, these are called ___ contractions

A

Labor

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26
Q

Labor contractions are thought to be mediated by a ___ mechanism

A

Positive feedback –> stretching of the cervix by the fetal head increases the contractility of the uterus; more stretch=more contractions

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27
Q

When the fetus drops lower in the uterus, it causes cervical stretch. Cervical stretch will cause __ release from the posterior pituitary which stimulates uterine contractions. Uterine contractions will also stimulate ___ release, which itself increases the intensity of uterine contractions.

A

Oxytocin

PG

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28
Q

When increased uterine activity stretches the cervix, oxytocin is released through the __ reflex

A

Ferguson

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29
Q

___ is the process by which the cervix prepares for delivery. After the baby has engaged in the pelvis, it gradually drops closer to the cervix; the cervix will gradually soften, shorten, and become thinner (cervical thinning)

A

Effacement

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30
Q

Effacement is measured in these percentages:

A

50%: pt is halfway to being completely effaced

100%: cervix is paper-thin and labor is right around the corner

31
Q

Describe the contraction period and average duration of dilation and effacement:

A

Contractions less than 10 min apart

Average 7-12 hrs in duration

32
Q

During ___, the cervix is fully dilated (10 cm) and contractions are strongest at top pushing the fetus downward

A

Descent and expulsion

33
Q

What is the average duration of descent and expulsion?

A

Average 20-50 min in duration

34
Q

___ is when the uterus contracts, reducing the area of attachment. Separation of the placenta results in bleeding and clotting and synthetic oxytocin is sometimes given to assist uterine contractions

A

Expulsion of the placenta

35
Q

What is the average duration of expulsion of the placenta?

A

About 15 minutes

36
Q

What are the 2 main types of prolonged labor?

A
  • Latent (early) phase of labor –> greater than 8 hours
  • Later phase –> active phase of labor is greater than 12 hours

Causes include: poor uterine contractions, baby’s position or size being abnormal, issues with the pelvis or birth canal

37
Q

What are main causes of obstructed labor or labor dystocia?

A

A large or abnormally positioned baby, small pelvis, problems with the birth canal.

Results in prolonged labor, pt may be required to have C section

38
Q

__ is defined as labor beginning prematurely, before the 37th week of pregnancy. It occurs in ~12% of all pregnancies, uterine contractions cause the cervix to open earlier than normal and baby is at risk for health problems

A

Preterm labor

39
Q

What are possible medical risk factors of preterm labor?

What are possible lifestyle risk factors for preterm labor?

A

UTI’s, certain uterine or cervical abnormalities, chronic illness (HBP, kidney disease, diabetes)

Smoking, drinking alcohol, drug abuse, high levels of stress

40
Q

___ is when the integrity of the myometrial wall is breached. It is spontaneous or traumatic tear and typically occurs during active labor but may also develop during late pregnancy

A

Ruptured uterus

41
Q

What are risk factors/causes of a ruptured uterus?

What are signs/symtpoms of a ruptured uterus?

A

Uterine scar from a previous C section, dysfunctional/prolonged labor, labor augmentation by oxytocin or PGs, excessive manual pressure applied to the fundus during delivery

Abdominal pain and vaginal bleeding, deterioration of the fetal heart rate (a leading sign), loss of fetal station of manual vaginal exam (cardinal sign), intra-abdominal bleeding leading to hypovolemic shock

42
Q

___ occurs only during pregnancy usually after week 20 and affects 5-8% of pregnancies. It is characterized by high BP and signs of damage to another organ system, often the kidneys. Other symptoms include proteinuria and generalized edema

A

Preeclampsia

43
Q

The placenta of women with preeclampsia is abnormal and characterized by poor ___ invasion

A

Trophoblastic

44
Q

___ refers to where the presenting part of the fetus is in the pelvis

A

Fetal station

45
Q

___ of the fetal station is part of the baby that leads the way through the birth canal. Most often, it is the babys head, but it can be a shoulder, buttocks, or feet

A

Presenting part

46
Q

___ are bone points on the mothers pelvis and is normally the narrowest part of the pelvis

A

Ischial spines (fetal station)

47
Q

___ is when the baby’s head is even with the ischial spines. The baby is said to be “engaged” when the largest part of the head has entered the pelvis

A

0 station

48
Q

If the presenting part lies above the ischial spines, the station is reported as a ___

A

Negative number from -1 to -5

49
Q

List the mechanism thought to be responsible for preeclampsia

A

Deficient trophoblast invasion of spiral arteries –> decreased uterine placental blood flow –> placental ischemia –> placental release of factors –> endothelial activation/dysfunction (Increase ANG II sensitivity) –> decreased renal pressure natriuresis and increased total peripheral resistance –> Hypertension

50
Q

The fundamental secretory unit of the breast is the ___

A

Alveolus

51
Q

The breast consists of a series of secretory lobules, which empty into ___

The ___ duct carries secretions to the outside

A

Ductules –> ductules from 15-20 lobules combine into a duct, which widens at the ampulla (small reservoir)

Lactiferous

52
Q

___ are organized into lobules, each of which drains into a ductule

A

Alveoli

53
Q

Each alveolus consists of ___ cells that secrete milk, as well as ___ cells which are surrounded by adipose cells

A

Secretory epithelial cells (alveolar cells)

Contractile myoepithelial cells

54
Q

During pregnancy, gradual increases in levels of ___ lead to full development of the breasts

A

Prolactin and hPL as well as very high levels of estrogens and progesterone

55
Q

__ hormones promote proliferation of alveolar and duct cells

___ hormones promote initiation of milk production by alveolar cells

___ hormones promote contraction of myoepithelial cells and thus milk ejection

___ hormones maintain milk production after it has been established

A

Mammogenic

Lactogenic

Galactokinetic

Galactopoietic

56
Q

During the secretory pathway of milk secretion, the milk proteins ___ and __ are synthesized in the ER and sorted to the golgi apparatus. Alveolar cells then add ___ and phosphate to the lumen of the golgi. ___ enzyme in the lumen of the golgi catalyzes synthesis of lactose and has a galactosyl transferase and lactalbumin component. Water enters the secretory vesicle by ___ and vesicle contents are emptied into the alveolar lumen by ___

A

Lactalbumin and casein

Ca2+

Lactose synthetase

Osmosis

Exocytosis

57
Q

During the transcellular endocytosis and exocytosis pathway route of milk secretion, maternal immunoglobulins, primarily Ig_, are taken up by endocytosis through the basolateral membrane. These Igs are transported to the apical membrane and secreted via ___. The GI tract of the infant takes up these Igs, which confers temporary immunity

A

IgA

Exocytosis

58
Q

During the lipid pathway of milk secretion, fats that predominate in the milk (longer chain FAs > 16 carbons) originate from diet or fat stores. FA’s form lipid droplets (milk lipids) which move to the ___ membrane which surrounds the droplets and pinches off, secreting milk lipids into the lumen in a membrane-bound sac

A

Apical

59
Q

During transcellular salt and water transport of milk secretion, various transport processes at the apical and basolateral membranes move small electrolytes from the interstitial fluid into the lumen of the alveolus. Water follows an osmotic gradient generated primarily by ___

A

Lactose (present at a final concentration of ~200 mM) and, to a lesser extent, by the electrolytes

60
Q

During the paracellular pathway of milk secretion, salt and water can also move into the lumen of the alveolus through __. Cells, primarily ___, squeeze between cells and enter the milk

A

Tight junctions

Leukocytes

61
Q

During pregnancy, ___ is secreted by the anterior pituitary which stimulates milk production. However, despite the fact that prolactin levels increase 20x fold, the action of prolactin is inhibited by high ___ during pregnancy

A

Prolactin

Estrogen and progesterone

62
Q

___ is a thin, yellowish milk-like substance secreted the first few days after parturition, it contains a high concentration of Igs

A

Colostrum

63
Q

Describe levels of prolactin, estrogen, progesterone in the initiation of lactation:

A

Prolactin increases

Estrogen and progesterone decrease

64
Q

__ is the most powerful physiological stimulus for prolactin release. It inhibits hypothalamic dopaminergic neurons and is the primary neural stimulus post-parturition

A

Suckling

65
Q

Prolactin is the classic lactogenic hormone which increases milk synthesis by ___ cells

A

Mammary alveolar

66
Q

Neural signals from suckling feedback to the hypothalamus to decrease ___ release which removes inhibition and results in an increase in prolactin

A

Dopamine (prolactin inhibitory factor, PIF)

Feedback also decreases release of GnRH with resulting decreases in LH and FSH

67
Q

High levels of prolactin may lead to ___

A

Lactational amenorrhea

68
Q

Actions of prolactin on the mammary glands include:

A
  • Promotion of mammary growth (mammogenic effect)
  • Initiation of milk secretion (lactogenic effect)
  • Maintenance of milk production once it has been established (galactopoietic effect)
69
Q

__, which can promote uterine contraction, also enhances milk ejection (“let down”) by stimulating the contraction of the network of myoepithelial cells surrounding the alveoli and ducts of the breast (galactokinetic effect)

A

Oxytocin –> positive feedback by suckling causes more oxytocin to be synthesized and released

70
Q

The suckling stimuli activates ___ pathways from the breast to the SC and then to the hypothalmus. ___ release is inhibited from the hypothalamus, which releases inhibition of lactotrophs and results in release of prolactin, which stimulates milk production. SC neurons then stimulate production and release of ___ from the posterior pituitary and circulates to interact with receptors on myoepithelial cells of breast resulting in “let down” of milk. Spinal cord neurons inhibit the ___ areas of the hypothalamus causing a fall in GnRH production resulting in decreased release of LH and FSH and inhibits the ovarian cycle

A

Afferent neural

Dopamine (PIF)

Oxytocin

Arcuate and preoptic

71
Q

In utero, the transfer of maternal Abs occurs across the ___ and this protection tapers off quickly after birth

A

Placenta

72
Q

Breast milk contains a number of different agents to protect the infant, including:

A

Secretory IgA

WBCs: neutrophils and macrophages

Growth factors: EGF, Nerve GF, IGF

73
Q

The birth process is ___ weeks after fertilization (fetal age) and ___ weeks after the last menstrual period

A

38

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Reproductive And Development (16 decks)

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