Pregnancy - 2/25 Lopez Flashcards by Alex Hamidi

Males with what # of sperm are considered infertile?

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How does estrogen aid sperm in fertilization?

Causes cervix to secrete watery mucus

Causes contractions of myometrium to hope propel sperm upward toward the oviduct

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What barriers must the sperm breach during fertilization?

Expanded cumulus (corona Radiata)
ZP
PM of egg (oolemma)

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At what point is it considered the end of fertilization and the beginning of embryonic development?

Mingling of chromosomes (syngamy)

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What is compaction?

Cells of morula tightly bound by desmosomes and gap junctions

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How does a cavity form inside the morula?

Active Transport of Na from trophoblast cells

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How will the blastocyst divide?

Into outer trophoectoderm (placenta)

ICM (pluripotent)

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What are pinopods?

When do they appear?

How is their development enhanced?
Inhibited?

Small, finger-like protrusions on endometrial cells

Between day 19-21

Enhanced: Progesterone
Inhibited: Estrogen

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Pinopods endocytose macromolecules and uterine fluid, what does this allow?

Embryo and uterine epithelium to approximate close to one another

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What does the blastocyst release that is immunosuppressive?

PAF
hCG
PGE2
IL-1a, IL-6
IFN-a
LIF
CSF
Early pregnancy factor, immunosuppressive factor

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What releases hCG?

What does it do?

Trophoblast of blastocyst

Sustains CL
Is an autocrine factor that promotes trophoblast growth and placental development

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When is implantation initiated?

When blastocyst comes into contact with uterine wall

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Roles of synctiotrophoblast? (5)

Express cadherins and integrins
Secretion of metalloproteases and other hydrolytic enzymes
Secrete hCG
Make progesterone to maintain pregnancy independently of CL
Phagocytosis and bidirectional placental transfer of gases, nutrients, and wastes

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What lytic factor found in the uterine cavity are essential for the dissolution of the zona pellucida?

What is this process called?

Plasmin

Hatching

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In the apposition stage of implantation, what contact is needed?

What glycoprotein May be involved in this process?

Endometrium (Decidua) and trophoblast

MUC1, expressed at apical surface of endometrial epithelium

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During adhesion of implantation, the trophoblast attaches to the uterine epithelium through what?

What ligand-receptor interactions?

Microvilli of the trophoblast

Integrins

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During invasion of implantation what happens to the trophoblast?

Differentiates into outer syncytiotrophoblast and inner cytotrophoblast

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During invasion of implantation, what do syncytiotrophoblast protrusions secrete?

What happens next?

TNF-a and B-catenin

Penetrate the BM of uterine epithelial cells and reach the uterine stroma

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Where does the blastocyst initially superficially implant?

Zona compacta

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What are decidualized stromal cells derived from?

What do they maintain?

What is the endometrial stroma transformed into?

Fibroblast-like cells w/in the endometrium

Progesterone receptors

Glycogen-filled decidual cells

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How is the primary chorionic villi formed?

Invading syncytiotrophoblast breaks through endometrial veins first, then arteries
Proliferation of cytotrophoblast

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How is the secondary chorionic villus formed?

Mesenchymal cells from XE mesoderm invade primary villi

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When is the tertiary villi formed?

Mesenchymal cells from fetal blood vessels de novo

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What is the mature placenta composed of?

What is the fx unit of the placenta?

Chorionic villi, intervillous space, Decidua basalis

Chorionic villi

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Where is maternal blood trapped? How does it drain after bathing the chorionic villi?

Intervillous space Venous orifices in the basal plate, enters larger maternal placental veins and flows into the uterine/pelvic veins

Fx of amniotic fluid?

Mechanical buffer | Fetus excretes waste through it

What mechanisms ensure adequate fetal oxygenation?

High CO/unit body weight of fetus | INC O2 carrying capacity of fetal blood

What has a higher pressure: umbilical vein or intervillous space?

Intervillous space (30-35)

How do urea and creatinine cross the placenta? Glucose?

Passive movement from fetus to mother FD from mother to fetus

How do lipid-soluble steroid hormones cross the placenta? Amino acids?

Simple Diffusion Secondary Active Transport

How do vitamins and minerals cross the placenta?

Active transport

How do LDL, transferrin, hormones (insulin), and IgG cross the placenta?

receptor mediated endocytosis - placenta takes up large molecules from the mother

What are the main hormones the placenta makes?

hCG and hPL

Antibodies are used to detect for what in suspected pregnancy? What does this hormone bind with high affinity?

B-hCG LH receptor

What is the primary action of hCG? What can it cause?

Stimulate LH receptors on CL Nausea and morning sickness

What is another name for hPL? What effect does it have on insulin? Glucose? Lipolytic actions?

Human chorionic somatomammotropin Antagonist to insulin -> contributes to DM INC glucose availability by inhibits maternal glucose uptake Help mother shift to use of FFA for energy

What do syncytiotrophoblasts express high levels of what? DO NOT express what? What receptors do they express and what do they do?

CYP11a (desmolase) 3B-HSD1 17,20 lyase/desmolase (CYP17) LDL that import cholesterol from the maternal blood

When is histotrophic nutrition important? What simulates secretion from uterine glands inducing this nutrition?

1st trimester Progesterone

What inhibitory effects does progesterone have?

Inhibits myometrium contraction | Prevents release of paracrine factors that leads to menstruation

When is the window of receptivity? What is assoc w/ the receptive phase?

Day 20-24 INC adhesivity of endometrial epithelium INC expression of Integrins and cadherins DEC expression of mucins

Name the following: E1 E2 E3

Estrone Estradiol Estriol

What is the major estrogen during pregnancy?

Estriol

What rescues the CL so that it can continue to secrete progesterone and estrogen? What secretes these hormones later?

hCG from synctiotrophoblast Placenta by 8 weeks of gestation

What enzymes does placenta lack? What are they needed for?

17a-hydroxylase 17-20-desmolase These are needed to synthesize estrone and estradiol Lacks 16a-hydroxylase Needed to synthesize estriol

What enzymes does the fetus lack? | Cannot produce what?

3B-HSD and Aromatase | Estrone (precursor to estradiol)

Since the fetus lacks 3B-HSD and Aromatase, what is the most downstream product it can make?

DHEA

What must happen to DHEA so that steriodogenesis can occur?

Sulfatase in the placenta removes the sulfate groups

CO and blood volume increase during pregnancy due to what? When does blood volume expand rapidly?

Aldosterone 2nd trimester

What is the reason for a fall in mean arterial pressure?

Vasodilating effects of progesterone and estradiol which cause a DEC in peripheral vascular resistance

How does progesterone affect respiration?

INC alveolar ventilation by INC tidal volume

During what stage of labor is there an INC in the # of gap junctions between myometrial cells and an INC in the # of oxytocin receptors? What is happening in this stage?

1 Uterine awakening, initiation of parturition, extending to complete cervical dilation

What hormone increases the degree of uterine contractility? What receptors does this stimulate the synthesis of?

Estrogen Oxytocin receptors

What is believed to initiate labor? How is their synthesis stimulated? What else stimulates their production?

PGs (Mainly PGF2a and PGE2) Estrogen from arachidonic acid in fetus and oxytocin in uterine cells Uterine stretch

When is the uterus sensitive to oxytocin? PGs?

End of pregnancy Throughout pregnancy

What is the Ferguson reflex?

Oxytocin released in response to stretch of the cervix, thus stimulating uterine contractions

What produces relaxin? Effect?

CL, placenta, Decidua Keeps uterus quiescent during pregnancy Softens and dilates cervix during labor

What from the fetus is responsible for exciting the uterus? Uterine stimulant? Intensity of uterine contractions?

Oxytocin Cortisol PGs

During pregnancy the uterus undergoes episode of weak and slow rhythmic contractions called what? When are contractions called labor contractions?

Braxton Hicks contractions Stretching of the cervix, forcing baby through birth canal

What is prolonged labor? What types? Causes?

Labor more than 18-24 hours Latent(early) > 8 hours and active phase is >12 hours Poor uterine contractions, large baby, abnormal position, pelvis or birth canal problem

What is labor dystocia? Cause? Results and risks?

Obstructed labor even though uterus is contracting normally Large baby, abnormal position, small pelvis Baby not getting enough O2, mother gets infection, uterine rupture, bleeding

What is classified as a preterm labor? Medical risk factors? Lifestyle risk factors?

Before 37 weeks UTI, cervical abnormalities, chronic illness (HTN, DM) Smoking, alcohol, drugs, stress

What is a ruptured uterus? When does it normally occur? Risk factors? Sx?

Integrity of myometrial wall is breached Active labor or late pregnancy Uterine scar from previous C-section, prolonged labor, etc Abdominal pain, vaginal bleeding, DEC fetal HR, loss of fetal station on manual vaginal exam

When does preeclampsia occur? Characterized by what?

ONLY during pregnancy, after week 20 HTN and proteinuria, kidney damage

What is the most narrow part of mother's pelvis?

Between ischial spines

What do mammogenic hormones do? Lactogenic?

Promote proliferation of alveolar and duct cells Promote initiation of milk production from alveolar cells

What do galactokinetic hormones do? Galactopoietic?

Promote contraction of myoepithelial cels -> milk ejection Maintain milk production

What is the major galactokinetic hormone? Galactopoietic?

Oxytocin Prolactin

What milk proteins are involved in the secretory pathway? What enzyme in the lumen of the Golgi?

Lactalbumin and casein Lactose synthetase

What is involved in the transcellular endo/exocytosis in secretion of milk?

IgA

How do alveolar cells secrete milk via the lipid pathway?

Long chain F.A. From diet and fat stores, and from lipid droplets

How do alveolar cells secrete milk in the transcellular salt and water transport mechanism?

Small electrolytes move from interstitial fluid into lumen of alveolus Water follows osmotic gradient generated by lactose

How do alveolar cells secrete milk via the paracellular pathway?

Salt and water move into lumen through tight junctions | Leukocytes squeeze between cells and enter the milk

What is secreted by the ant pituitary during pregnancy? How is its action inhibited?

Prolactin High levels of estrogen and progesterone

At the end of pregnancy milk production is suppressed except for what? What does it contain?

Colostrum High [ ] of Igs

What is the most powerful physiological stimulus for prolactin release? What does it inhibit?

Suckling Hypothalamic dopaminergic neurons

Neural signals from suckling feedback to the hypothalamus to decrease production of what? Then what gets decreased?

GnRH LH and FSH

What effect does oxytocin have on breasts and milk lactation? How does suckling effect its release?

Enhances milk ejection (galactokinetic effect) Positively feedbacks

How does suckling affect the GnRH? What else does it affect?

Inhibits the arcuate and pre optic area of hypothalamus -> fall in GnRH DEC in LH and FSH and inhibits the ovarian cycle

What does breast milk contain to protect the infant?

IgA Neutrophils and macrophages EGF, NFG, IGF

When does fertilization occur?

Day 15/16 of menstrual cycle

The fetus never makes anything beyond _______ bc it lacks 3B-HSD and Aromatase?

DHEA and 16a-hydroxy-DHEA

Where is pregnenolone made? Where does it go? What happens to it? What else happens there?

Placenta Fetus Sulfated DHEA and 16a-OH-DHEA also sulfated

When enzymes does the fetus have and where?

17a-hydroxylase and 17-20-desmolase in adrenals 16a-hydroxylase in liver

In the placenta, pregnenolone -> progesterone via what enzyme?

3B-HSD

DHEA -> Estradiol where and with what enzymes? Estradiol -> Estrone via what enzyme?

3B-HSD, 17B-HSD, Aromatase in placenta 17B-HSD