TBL: Pregnancy Flashcards by Megan Foggia

What cells produce estrogen?

granulosa and thecal cells

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Estrogen: granulosa and thecal cells
(blank) of endometrium
(blank) of the cervical mucus
Stimulate pituitary to secrete (blank)
LH surge at mid-cycle-> (blank)
Stimulate (blank) production

proliferation; thinning; LH; ovulation; progesterone

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What causes the completion of meiosis I and the transformation into a Graffian/preovulatory follicle?

LH surge

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Graffian follicles are arrested in what phase 3 hours before ovulation?

metaphase of meiosis II

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Ovarian surface:
LH↑→ (blank) ↑→ Digestions of fibers around the follicle
LH↑→ (blank) ↑→ Muscular contraction

collagenase; prostaglandin

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During ovulation, what increases digestions of fibers around the follicle?

increased LH leading to increased collagenase

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During ovulation, what increases muscular contraction?

increased LH leading to increased prostaglandin

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The corpus luteum contains these two types of lutean cells

granulosa cells

thecal cells

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The corpus luteum secretes primarily (blank)

progesterone

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Together, progesterone and estrogen prepare the uterine mucosa for implantation by eliciting the (blank) stage

progestational/secretory

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How is the ovulated oocyte transported?

Ovulated oocyte is captured by the sweeping movement of the fimbriae of the uterine tube and by the motion of cilia on the epithelial lining

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How long does it take for the oocyte to move from the ampulla to the uterine lumen?

3-4 days

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Where does fertilization occur in the uterine tube?

at the ampulla

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If there is no fertilization, what does the corpus luteum form? What steroid declines? What occurs?!

lutean cells apoptosis, forms corpus albicans, progesterone decreases, menstrual bleeding begins

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If the oocyte gets fertilized, what is secreted by the syncytiotrophoblast to promote further growth?

hCG

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Progesterone production will continue until what month? At this point, trophoblastic secretion of progesterone becomes adequate.

4th month

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Discuss the transport of sperm from the testis to ejaculation.

testis –> epididymis (maturation for 2 weeks) –> rapid transit through ductus deferens –> addition of fluid from seminal vesicle –> addition of prostatic fluid

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Discuss the transport of sperm as it enters the vag

Sperm deposited in upper vag –> pass through cervix (fast and slow phase) –> pass through uterus –> enter uterine tubes –> traverse uterine tube by swimming and contractions of the tube –> only a small number of sperm actually near the egg at a given time

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250,000,000 sperm are deposited in the vagina, and 100,000 sperm reach the uterine cavity. How many sperm arrive at the distal end of the fallopian tube?

50 or less

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Once they’ve come through the vag, the cervix, the uterus, where are sperm delayed? For how long?

delayed at isthmus-ampulla junction where fertilization occurs (1-2 days)
delayed at utero-tubal junction (2-3 days)

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At what day does the egg enter the uterine cavity as a morula?

Days 3-4

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At what day does the blastocyst implant?

Day 7

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Maturation of sperm in female reproductive tract → Removal of the glycoprotein coat and seminal plasma proteins from the sperm plasma membrane

Capacitation

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Release of enzyme by sperm to dissolve zona pellucida

Acrosome reaction

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3 phases of fertilization

1. penetration of the corona radiata 2. penetration of the zona pellucida 3. fusion of the oocyte and sperm cell membranes

Steps 1-5 of fertilization

1. sperm penetrates zona pellucida (15-25 mins) 2. perivitelline space (<1 min) 3. perivitelline membrane - release of cortical granules - completion of second meiotic division and formation of polar body 4. male and female pronuclei visible (2-3 hours) 5. mitotic spindle and first cleavage (24 hours)

3 things that entry of sperm into the oocyte triggers

1. cortical and zona reactions to prevent polyspermy 2. oocyte completes meiosis II 3. egg is activated

Sperm enters egg causing rapid depolarization of plasma membrane of egg - hardening of zona pellucida and inactivation of sperm receptors - second meiotic division and cortical reaction completed - male pronucleus forming - female pronucleus forming - pronuclei join - metaphase of first cleavage division

Main events during fertilization

3 results of fertilization:

restoration of diploid number of chromosomes sex determination initiation of cleavage

Blastomeres begin to form in 2, 4, and 8 cell stages and become compact. The inner and outer cells become (blank). The blastomeres become a (blank) on day 3 and there are about 16 cells.

segregated; morula

By day 3, in the morula, the inner cell mass becomes the (blank) while the outer cell mass becomes the (blank)

embryo proper; trophoblast

At about day 4, the differentiated morula will become a (blank) - the ZP degenerates, uterine fluid penetrates - a blastocele (cavity) forms and the inner cell mass becomes the (blank), while the outer cell mass becomes the (blank)

blastocyst; embryoblast; trophoblast

At about what day does the blastocyst implant in the uterine wall?

Day 5.5 - 6

During what phase of the uterine cycle does implantation occur? What are the three layers of the endometrium? At what site does implantation occur?

secretory phase; compact layer, spongy layer, basal layer; along the anterior or posterior wall

What are the effects of progesterone on the uterine endometrium?

stromal cells-->highly secretory -->secrete glycogen, proteins, lipids --> decidual cells-->decidua

(blank) cells invade the decidua (decidual reaction) and release nutrients to the embryo for growth and development. This provides the main source of nutrition for weeks 1-8. Gradually, this is replaced by (blank) nutrition

trophoblast; placenta

A primary villus has these two components. What happens when it becomes a secondary villus? What forms up in the center? Tertiary?

cytotrophoblastic core + syncytial layer; mesodermal cells penetrate the core of the primary villi; mesoderm core; mesoderm cells + blood cells and blood vessels

At the end of (blank) week, maternal vessels penetrate the (blank) shell to enter intervillous spaces, which surround the villi. Capillaries in the villi are in contact with vessels in the chorionic plate and the connecting stalk, which in turn are connected to intraembryonic vessels.

3rd; cytotrophoblastic

At the end of 3rd week, 3rd and 2nd villi give the trophoblast a radial shape. Intervillous spaces are lined with syncytium. Cytotrophoblastic cells surround the entire trophoblast and are in contact with endometrium. The embryo is suspended in the (blank) by the connecting stalk.

radial; chorionic cavity

Function of the placenta: Diffusion from mother to fetus of (blank) Diffusion from fetus to mother of (blank)

``` foodstuffs, O2 excretory products (nonprotein nitrogens, urea, uric acid, creatinine) ```

How much higher is the concentration of fetal Hb than the mother's?

50%

Bohr effect-hemoglobin can bind more oxygen at a low (blank) than a high (blank)

PCO2; PCO2

What is the origin of hCG? When is the onset of secretion? When is its peak? What is its function?

syncytial trophoblast cells 8-9 days after ovulation (doubles every 2-3 days) 10-12 weeks prevention of involution of the corpus luteum

What is the clinical utility of hCG?

Can diagnose a pregnancy 7-10 days after fertilization

Why is the exponential rise of hCG critical?

It "rescues" the corpus luteum, which would have been deprived of progesterone

What is the target of hCG?

corpus luteum, fetal Leydig cells

hCG has a similar composition to (blank), but has more CHO, thus has a longer half-life

What is the cell origin of estrogens? What are they synthesized from? Can the placenta convert progesterone to androgens?

syncytial trophoblast cells; synthesized from androgens produced by the fetal and maternal adrenal glands; no

What does large scale production of estrogen do to uterus, breasts, external genitalia? What does it do to the pelvic ligament?

enlargement; relaxation of pelvic ligament

(blank) is essential for implantation and the maintenance of pregnancy: Causes (blank) of the uterus to avoid spontaneous abortion, decidualization of the endometrial stroma (nutrition), and increases secretion from the (blank) (nutrition to the early embryo)

progesterone; relaxation; fallopian tubes

Progesterone + estrogens inhibit the (blank) pulse generator, which reduces these two things; + CL is still alive, so there is a blockade of new wave of folliculogenesis

GnRH; FSH/LH

What is the origin of human chorionic somatomammotropin/human placental lactogen?

synctial trophoblast

What is the composition of human chorionic somatomammotropin/human placental lactogen?

polypeptide

Actions of human chorionic somatomammotropin/human placental lactogen?

growth of mammary gland? fetal growth? decreased glucose tolerance?

Secretion of human chorionic somatomammotropin/human placental lactogen increases until the (blank) week

36th

What's the clinical utility of human chorionic somatomammotropin/human placental lactogen?

diagnosis of decreased placental mass (ex: placental infarction)

human chorionic somatomammotropin/human placental lactogen has similar effects as (blank)

``` Corticosteroid secretion Relaxin secretion: CL and placenta Pituitary: ↑Corticotropin, thyrotropin, and prolactin ↓ FSH and LH ```

Other hormonal factors in pregnancy

Produced by the corpus luteum of the ovary, the breast and, during pregnancy, also by the placenta, chorion, and decidua. Its role or necessity in human pregnancy remains under investigation, as in humans its peak is reached during the first trimester, not toward the end of pregnancy

Relaxin

In animals, widens the pubic bone and facilitates labor softens the cervix (cervical ripening), and relaxes the uterine musculature affects collagen metabolism, inhibiting collagen synthesis and enhancing its breakdown by increasing matrix metalloproteinases. enhances angiogenesis and is a potent renal vasodilator

relaxin

About how much weight is gained during pregnancy? | By what percent does metabolism increase?

24 lbs; 15%

Changes in maternal circulatory system: Cardiac output: ↑(blank)% by 27th week, followed by a fall in the last 8 weeks for unknown reasons Blood volume: (blank)% above normal due to fluid retention Respiration: (blank)% above normal Amniotic fluid: 500-1000ml

30-40% 30% 20%

5%, hypertension + leakage of protein into urine

preeclampsia

extreme degree of preeclampsia

eclampsia

During parturition (birth of the baby), there is increased uterine excitability and strong rhythmical (blank)

contractions

Hormonal factors that increase the uterine contractility: Increased ratio of (blank) to progesterone: after 7th month, (blank) continue to increase, while progesterone levels remain Fetal hormones: oxytocin from the fetus’s pituitary; cortisol from adrenal glands; prostaglandins

estrogens; estrogens

Secreted by the neurohypophysis; causes uterine contraction; receptors on uterine muscle cells ↑↑ Secretion ↑↑ Stretching and irritation of uterine cervix cause its increase

oxytocin

What fetal hormones increase the uterine contractility?

oxytocin, cortisol, prostaglandins

Mechanical factors that increase the uterine contractility?

stretch of the uterine musculature | stretch or irritation of the cervix

Weak and slow labor contractions at the onset of labor

Braxton Hicks contractions

What triggers the onset of labor?

Positive feedback theory: stretching of the cervix by the fetus’s head →reflex →contraction of the uterine body →more stretching →more contraction

(blank) administration can induce labor, but it only starts to increase after the beginning of labor; hastens delivery, promotes placental delivery; reduces bleeding

oxytocin

cervix dilation to the size of the head of the fetus; ~8-24 h for the 1st pregnancy; can be a few minutes after

1st stage of labor

membrane rapture; loss of amniotic fluid; head out; 1- 30 min

2nd stage of labor

During the first stage of labor, labor pains are due to (blank) hypogastric nerves; During the second stage, (blank) nerves to spinal cord and brain

visceral sensory; somatic

When does involution of the uterus occur after birth?

4-5 weeks

This hormone acts on the lactiferous ducts

estrogen

This hormone acts on the lobulo-alveolar system

progesterone

These two hormones are important for alveoli + milk secretion

hCS/hPL and prolactin

(blank) levels increase 10-20 times during the 5th week until birth, but milk is not produces because of the presence of what? After birth when these hormones drop, milk production can begin.

prolactin; estrogens and progesterone

T/F: there is suppression of the female ovarian cycles in nursing mothers for many months after delivery

true

When lactating, women suppress (blank) pulse generator activity

GnRH

sensory impulses from nipples to spinal cord and then to hypothalamus →secretion of oxytocin from posterior pituitary → contraction of myoepithelial cells → milk from alveoli to ducts 30 sec-1min, milk ejection or let-down Reflex does not diminish with time Milk removal is required for maintenance of lactation

ejection reflex