Physiology of Pregnancy, Parturition and Lactation Flashcards

1
Q

The female reproductive tract is an important regulator of sperm transport. The main player is estrogen which does who two things to help the sperm each it’s target

A
  1. Estrogen causes the cervix to produce a watery mucus

2. estrogen causes contraction of the myometirum to help propel sperm upward toward the oviduct

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2
Q

what three barriers must the sperm breach in order to get to the egg?

A
  1. cumulus
  2. zona pellucida
  3. plasma membrane of the egg (aka oolemma)
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3
Q

which ZP glycoprotein must the sperm interact with to begin fertilization?

A

ZP3

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4
Q

What is the acrosmal reaction?

A

Increase in Ca inside the sperm cell triggers fusion of the outer acrosomal membrane with the sperm cells plasma membrane and results in the exocytosis of most of the acrosomal contents

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5
Q

what is the corticol reaction?

A

Initiated by increase in Ca inside the oocyte .
-massive exocytsosis of corticol granules seen shortly after sperm - oocyte fusion. the release of these granules release enzymes that act on glycoproteins in the zona pellucida and cause them to harden

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6
Q

what process is considered the end of fertilization and the beginning of embryonic devlelopment?

A

The mingling of chromosome (syngamy)

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7
Q

around what day does fertilization typically occur?

A

Day 15 or 16 of menstrual cycle

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8
Q

by day 3, how many cleavage has occurred and what is it called?

A

3 cleavage and is called a 16 cell morula

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9
Q

by what day does implantation usuaully occur?

A

by day 6 or 7 following ovulation

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10
Q

Trophectoderm becomes the _ and the inner cell mass becomes _.

A

Trophectoderm forms the placenta and XE tissues

ICM = embryo

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11
Q

At the time of implantation, the trophoblast differentiates into 2 cell types:

A
  1. cytotrophoblasts (inner cell layer)

2. Syncytiotrophoblasts (outer layer of multinuclear and multicellular ells; w/o cellular boundaries)

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12
Q

what secretes hCG?

A

trophoblasts cells of the blastocyst

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13
Q

which cells are adhesive (has adherins and integrins that bind to uteirne surface epithelial), invasive and has endocrine functions such that it releases hcG at the onset of implantation, and make progesterone.

A

syncytiotrophoblasts

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14
Q

what plays the major role int he dissolution of the zona pellucida?

A

lytic factors in the endometrial cavity. Such factors include plasmin which appears in the plasminogen form int he uterine cavity, and the blastocyst contains factors that can activate it

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15
Q

what are three stages of implantation/

A

apposition
adhesion
invasion

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16
Q

what is apposition?

A
  • earliest contact between the blastocyst wall, trophoectoderm, and endometrial epithelium
  • usually occurs where there is a mslal crypt in the endometrium
  • Apposition starts at the place on the blastocyst where there has been enough lysis and that portion meets with the decidua
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17
Q

what endometrial surface epithelial cells is involved in apposition?

A

MUC1

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18
Q

In the adhesion stage of implantation, trohoblast attaches to the uterine epithelium through microvilli found on _

A

the trophoblast

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19
Q

during which stage of implantation, does the trophoblastic cells rapidly proliderate and differentiate into the inner cytotrophoblast and the outer syncytiotrophoblast

A

invasion

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20
Q

In the decidualization process, the stromal cells derived from the fibroblast-like cells within the endometrium require _ to maintain their progesterone receptors.

A

progesterone

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21
Q

in the development of the placenta, the invading syncytiotrophoblast breaks through into the endometrail _ first and then into the _

A

veins first and then arteries.

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22
Q

proliferation of which (cytotophoblast or syntiotrophoblast) creates small mounds that forms the primary chorionic vili?

A

cytotrophoblast

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23
Q

how is the secondary chorionic villi formed?

A

mesenchymal cells from the XE mesoderm invade the primary chorionic villi

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24
Q

when does secondary chorionic villi become tertiary?

A

when the mesenchymal cells form fetal blood vessels de novo

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25
Q

the mature placenta is composed of three majjor structure:

A
  1. chorionic villi
  2. intervillous space
  3. decidual basalis
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26
Q

what represents the functional unit of the placenta and is responsible for greatly increasing the surface area for maternal-fetal exchange?

A

Chorionic villi

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27
Q

what factors regulate maternal blood flow in the intervillous space?

A
  1. maternal arterial blood pressure,
  2. intra-uterine pressure
  3. pattern of uterine contraction
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28
Q

Do umbilical arteries carry oxygenated or deoxygenated blood?

A

deoxygenated blood, unlike systemic arteries after birth.

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29
Q

what imporant functions do amniotic fluid have?

A
  1. serves as a mechanical buffer protecting the fetus from external physical insults
  2. fetus excretes waste products through it
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30
Q

describe the gas composition of maternal blood coming into the intervillous space.

A

It’s similar to that of system arterial blood: P02 = 100 mHg; PCO2 = 40 mm Hg; pH = 7.4

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31
Q

What causes the drop in Po2 of the blood int he intervillous space?

A

The diffusion of O2 from the maternal blood into the chorionic villi of the fetus

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32
Q

Despite the relatively low Po2 of the maternal blood int he intervillous space, the fetus does not suffer fromlack of O2, why?

A

Fetal Hb has a much higher affinity for O2 than does maternal Hb, the fetal Hb can extract O2 from the maternal Hb

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33
Q

Does the following move across the placenta:

  1. waste prodcuts urea and creatinine
  2. Lipid-soluble steroid hormones
  3. glucose
  4. Amino acids
  5. Vitamins and minerals
  6. LDL, transferrin, hormones, ab
A
  1. passive movement
  2. simple diffusion; shuttle among the mother, the placenta and the fetus
  3. facilitated diffusion
  4. secondary active transport
  5. active transport
  6. receptor-mediated endocytosis
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34
Q

what is the first hormone produced by the syntiotrophoblast?

A

hCG

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35
Q

In pregnancy test, which subunit of hCG does antibodies bind to?

A

b-hcg

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36
Q

to what receptors do hCG bind to?

A

LH receptors

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37
Q

what is the 1/2 life of hcg?

A

up to 30 hrs

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38
Q

What is the primary action of hCG?

A

stimulate LH receptor on corpus luteum

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39
Q

hPL are structurelly similar to what other hormones?

A

GH and PRL

40
Q

by when can hPL be detected wihtin the syntiotorphoblast and int he materanl serum?

A

10 days in syncytiotrophoblat and 3 weeks in gestation

41
Q

hPL has antagonist action to what hormone?

A

insulin - contributes to the diabetogenicity of pregnancy.

42
Q

What are the actions of hPL?

A
  • protein-anabolic
  • lypolytic
  • increase glucose availability by inhibiting maternal glucose uptake
  • its lipolytic actions help the mother to shift to use the free fatty acids for energy
43
Q

which steroid synthesis/conversion enzymes do syntiotrophoblast express. Does not express?

A

Expresses: CYP11A1 (cholesterol demsolas); 3b-HSD1

Does not express: 17a-hydroxylase/17,20 lyase, 17,20 desmolase

44
Q

Do syncytiotrohoblast express LDL receptors?

A

Yes, helps to imortan cholesterol from the maternal blood

45
Q

the amount of progesteroll produced is similar to the amount of _

A

cholesterol

46
Q

During the first trimester, what is the main mode of maternal-to-fetal transfer of nutrients?

A

histotrophic nutrition stimulated by progesterone secretion

47
Q

what inhibits myometrial contraction and prevent the release of paracrine factors that lead to menstruation?

A

Progesterone

48
Q

which hormone induces the window or receptivity int he uterine endometrium

A

progesterone. window is around day 20-24

49
Q

after what 8 of gestation does coordinated biosynthetic activity of the maternal-placental-fetal unit maintains high levels of progesterone and estrogen?

A

Week 8

50
Q

which enzymes does the placenta lack?

A

17a hydroxylase
17,20 desmomlase which are needed for estrone and estradiol
-16a-hydroxylase needed for estriol

51
Q

where does the enzymes needed, that which the placenta lacks, come from?

A

fetal adrenal gland and liver. the mother provides the LDL particles

52
Q

which enzymes does the fetus lack?

A

3b-HSD, arotase

53
Q

which hormone is needed only by the mother, and so the fetus does not produce it

A

estrogen.

54
Q

which the fetus lacks 3b-HSD and aromatase, it cannot produce any hormones beyond_

A

DHEA and 16a-hydroxy-DHEA

55
Q

how does the fetus reduces the biological activity of steroid hormones intermediates that it does not need?

A

conjugates the intermediates to sulfates. DHEA and 16a-hydroxyase DHEA-S is also sulfnated, it get defulfonated after it moves to the placenta where fulfatase removes the sulfate group and deliveres to the mother

56
Q

During pregnancy, maternal CO and blood volume _ (increase or decrease)

A

increase

57
Q

explain how blood volume changes throughout pregnancy?

A

Starts to increase during 1st trimester, expands rapidly during 2nd and rises at a much lower rate durig 3rd and finally ahieves a plateaue during the last few weeks.
-overall blood volume slowly increases by 40-50%

58
Q

how does MAP change throughout pregnancy?

A

despite increase in plasma volume, MAP decrease during mid pregnancy and then rises during 3rd trimester, but remains lower than normal

59
Q

How does CO change during pregnancy?

A

increase during 1st (by 35-40%) but it increases only slightly during he 2nd and 3rd trimester (about 45%)

60
Q

How does tidal volume change during pregnancy?

A

Increase by about 40% –> increase alveolar ventilation

61
Q

what GI changes occur during pregnancy?

A

morning sickness (due to elevated hCG)

  • prolonged gastric empty time
  • decrease GI gastroesphogeal sphicter tone –> acid reflux)
  • decreased colonic motility –> increased water absorption and constipation
  • increase demand for dietary protein, iron, folic acid
62
Q

what contributes to the inactivity of the uterus during pregnancy?

A

progesterone and relaxin

63
Q

During parturition, what hormones increase and what is the it’s result?

A

Placenta produces corticotropin-releasing hormone and it promotes contraction by sensitizing uterus to prostaglandins and oxytocin. estrogen also plays a role in contraction

64
Q

Around what month does estrogen level start to increase while progesterone remain constant and has an effect of increased uterine contractility?

A

7th month and onward

65
Q

which hormone has a role in initiating labor, progesterone or estrogen

A

progesteone. synthesis of these are sitmulate dby estrogen from aracidonic acid in fetal membranes and by oxytocin in uterine cells.

66
Q

what hormone increaes the number of oxytocin receptors in the myometrial and decidual tissue of pregnant woman?

A

estrogen

67
Q

what is Ferguson reflex?

A

Stretch of the cervix which stimulates the release of oxytocin.

68
Q

These hormone binds to receptors on decidual celss during the 2nd stage of labor, thereby stimulating PGE2 a production.

A

oxytocin

69
Q

what cells produces relaxin?

A

corpus luteum, placenta and the decidua which keeps the uterus quescent during pregnancy. production and release of relaxin increase during labor; may soften and dilates cervix during labor

70
Q

To induce labor, the following fetal structure release what?
Fetal pituitay
fetal drenal
fetal placental membranes

A

fetal pituitary = oxytocin
fetal adrenal = cortisol
fetal placental membranes = Prostagland

71
Q

what are braxton hick’s contraction?

A

A periodic episode of weak and slow rhythmic contraction that the uterus undergoes throughout most of pregnancy. these contraction get extrememly strong during last hours of pregnancy

72
Q

What are labor contractions?

A

the end contractions of the braxton hick’s contraction that happen right before the baby is expelled. mediated by positive feedback mechanism

73
Q

what are the positive feedback mechanism involved in labor

A
  1. Uterine contractions stimulate PG release –> increase intensity of uteirne contraction
  2. Uterine activtiy stretches the cervix, thus stimulation gOT release through the ferguson reflex
  3. Because OT stimulates further uterine contraction, these contraction become self-perpetuating
74
Q

What is effacement?

A

process by which cervix prepares for delivery as the baby drops into the cervix and cervix gets thinner. Measured in %: 50% and 100% (cervix is paper thin and labor is right around the corner)

75
Q

what is the leading sign and cardinal sign of ruptured uterus?

A

leading sign: fetal heart deterioration

cardinal sign: loss of fetal station on manual vaginal exam

76
Q

what is preeclampsia?

A

Characerized by high blood pressure and signs of damage to another organ system, often the kidney. you may also see proteinuria and generaized edema. Could be due to abnormal placentaltion, immunollgic factor, prior or existing maternal pathology like hypertension, obesity, and hx of preeclampsia. Could be due to placental diseases like limited suply to uterine arteries, causing ischemia and endothelial damage with release of cytokines.

77
Q

what is a possible mechanism thought to be responsible for preclampsia?

A

deficient trophoblast invasion of spiral arteries leading to decreased uterine placental blood flow, leading to placental ischemia. Placental release of facotrs causes endothelial activation and dysfucntion leading to decreased renal pressure and increased total periheral resistance leading to hypertension

78
Q

If the presenting part lies above the sichial spine the station is repoarted as what?

A

a negative number from -1 to -5

79
Q

what factors contribute to full development of the breast?

A
  • increasing levels of prolactin and hCS

- high levels of estrogens and progesterones

80
Q

what are mammogenic, lactogenic and galactokinetic hormones?

A
mammogenic = promote proliferation of alveolar and duct cells
lactogenic = promote initiation of milk production by alveolar cells
galactokinetic = promote contraction of myoepithelial cells  and thus milk ejection 
galactopoietic = maintaing milk production after it has been estabished
81
Q

In the secretory pathway of alveoli secretion of milk components, where are lactoalbumin and casein synthesized?

A

In the ER and sorted in the golgi

82
Q

where is lactose synthesized?

A

In the lumen of the golgi via lactose synthetase and has two components galactosyl transferase and lactoalbumin

83
Q

Via what secretory pathway does mateanl Ig (IgA) enter breast milk?

A

transcellular endocytosis through the basolateral membrane. they are then transported to the apical membrane via exocytosis

84
Q

how is lipid added to breast milk?

A

Fats in the milk is ually long chain fatty acid >16 carbons, originate int he diet or fat stores. they form lipid droplets which move to apical memrbane from there they pinch off and is secretes the milk lipid into the lumen in the membrane bound sac.

85
Q

how is salt and water added to breast milk?

A

Water follows osmotic greadient generated by lactose.
salt is added via varous transport processes at the apical and basolateral membranes
-both can also move via tight junctions

86
Q

what is colostrum?

A

thin, yellowish milk-like substance secreted the first few days after parturition, contains a high concentration of Ig

87
Q

is prolactin mammogenic, lactogenic, or galactopoietic.

A

All three

88
Q

During lactation initiation how does prolactin level, estrogen progesterone levels change?

A

Prolactin increase

estrogen progesterone decrease

89
Q

which neurons are inhibited by suckling?

A

hypothalmic dopaminergic neurons

90
Q

what are the actions of RL on the mammary glands?

A
  1. promotionof mammary growth
  2. initiation of milk secretion
  3. maintenence of milk production once it has been established
91
Q

during lactaion what happens to the levels of PIF, GnRH, FSH, and LH

A

PIF increase

GNRH, FSH and LH decrease

92
Q

which hormone is responsible for stimulating ejection?

A

oxytocin

93
Q

What effect does suckling have on oxytocin levels?

A

Suckling is a positive feedback to synthesize and release more oxytocin

94
Q

name four effects suckling has on hormone release

A
  1. suckling stimuli activates afferent neural pathway from breast to spinal cord and then to hypothalamus
  2. PIF release is inhibited from the hypothalmaus
  3. spinal cord neuron stimulates production and release of oxytocin from posterior pituitary
  4. spinal cord neurons inhibit arcuate and preoptic area of the hypothalmus causing a fall in GnRH proeduction
95
Q

Breast milk contains what immune protectants for the baby?

A

-secretogy IgA
-WBC: neutrophils and macrophages
GF: EGF, NGF, and IGF