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What is the two cell stage of fetilization?

First three days of development in the fallopian tube


What is the morula and when does it arrive in the uterine cavity?

1. Solid Mass of Blastomere Cells-MORULA

2. Day 4- Arrives in the uterine cavity


1. What happens in Day 5?

2. What is the outter layer of this called?

3. Inner layer?

1. Blastocyst stage

2. Outer layer = Trophoblast= Placenta&Fetal Membranes

3. Inner layer = Cell Mass to become Embryo and Fluid


What day is "Hatching"?

Wat structures are involved? 5

Day 5


What happens on day 6-7?

Implantation-Trophoblast Invades Endometrium


Day 7-Implantation

1. In response to 17-OH progesterone from the corpus luteum, the endometrium glands are filled with what? 3

2. Implantation of the ________ takes several days.

3. The conceptus is genetically different from the mother. How many of the chromosomes are from mother?

4. Genetically foreign cells usually rejected by the immune system. This does not occur during normal pregnancy— why?



-mucus and a

-rich blood supply. (The secretory endometrium.)

2. blastocyst

3. Only half

4. due to modifications of the mother’s immune system


What are the stem cells of the placenta?




1. Placenta: Which cells are “Invasive” into decidua and myometrium (not too dissimilar to metastasizing cancer cells)?

2. “Invasive” into the ___________ which are remodeled into wide uteroplacental arteries (which anastomose with ______________ to form a lacunar system of low resistance).

3. Form core of villi (covered by what?)

1. Extravillous Cytotrophoblast (inner)

2. spiral arteries, endometrial veins

3. syncytiotrophoblast


Differentiation of Progenitor Villous Trophoblast Cells

1. These are able to become what?

2. Forms the placental villi with base of what with overlying syncytiotrophoblast on surface?

3. What does the Progenitor Villous Trophoblast Cells form?

4. What is its function? 3

5. Also, forms ____ umbilical arteries and ____ vein


2. cytotrophoblast cells (Langhans layer)

3. Specialized epithelium without distinct cell boundaries covering villous tree:


-transport of gases,

-nutrient and wastes as well as

-synthesis of peptide and steroid hormones that influence placental, fetal and maternal systems

5. two, one


Influenced by 1.____________ and later with invasion of trophoblasts (implantation), the 2.________ cells of the secretory endometrium become 3.__________ CELLS


1, progesterone

2. stromal



Decidual cells directly under implantation site form what? 2

1. the basal plate of the PLACENTA  (decidua basalis) and

2. a factor limiting myometrial invasion (placenta accreta, increta and percreta)


What always separate the embryonic circulation from maternal blood and decidua?


A layer of trophoblast cells


1. What is Nitabuch's layer?

2. Possible role in preventing what?

3. Allows separation of what?

1. A layer of fibrin between the boundary zone of compact endometrium and the cytotrophoblastic shell in the placenta

2. host/graft rejection

3. placenta after delivery


Functions of the Placenta? 6

1. The interface between mother and fetus

2. Prevents rejection of fetal allograft

3. Enables respiratory gas exchange

4. Transports nutrients

5. Eliminates fetal waste products

6. Secretes peptide and steroid hormones


Metabolic Functions of the Placenta


1. Glycogen synthesis –uptake of glucose from maternal circulation;  glycogen as an energy reserve


2. Cholesterol synthesis –  as a precursor for production of progesterone and estrogen


3. Removal of Lactate-a waste product of placental metabolism is transferred to maternal circulation


4. Protein metabolism


Placental Peptide Hormones


1. Human chorionic gonadotropin(hCG)

2 . Human placental lactogen (hPL)

3. Placental corticotropin-releasing hormone (CRH)



4. Insulin-like growth factors (IGF)-regulate fetal growth

5. Vascular endothelial growth factor (VEGF)

6. Placental growth factor



Describe the following functions of each of the hormones?

1. Human chorionic gonadotropin(hCG)?

2 . Human placental lactogen (hPL)?

3. Placental corticotropin-releasing hormone (CRH)? 2

1. Human chorionic gonadotropin(hCG)-maintains corpus luteum production of progesterone until placenta takes over at 6-8 weeks; regulates placental steroid production


2. Human placental lactogen (hPL)-antagonizes maternal secretion of insulin to increase fetal glucose supply


3. Placental corticotropin-releasing hormone (CRH) -

-stimulates fetal ACTH resulting in fetal adrenal making DHEA-S as precursor to placental estrogen

-in latter gestation, fetal cortisol stimulates CRH release which stimulates fetal ACTH that acts as an endocrine mediator of onset of labor



What are the placental Steriod hormones?



1. Progesterone

2. Estrogens

3. Enzymes to degreade maternal glucocorticoids


Describe the following functions of these hormones:

1. Progesterone?

2. Estrogens?

3. Enzymes to degreade maternal glucocorticoids?

1. Progesterone – maintains a non-contractile uterus; also anti-inflammatory and immunosuppressive to protect fetus

2. Estrogens – stimulated by placental HCG; also  maternal & fetal blood supply DHEAS (dehydroepiandrosterone sulfate) as substrate for additional estrogens (mostly from fetal adrenal)

3. Enzymes to DEGRADE  maternal Glucocorticoids – placenta regulates exposure of fetus to glucocorticoids. This has an important role in regulating fetal organ development and maturation


1. PLacental transfer/transport occurs where?

2. What are the kinds of transport across the placenta? 6



-CO2 and O2 exchange


-Amino acid: fetus dependent on these for protein synthesis

-Fatty acids from breakdown of maternal triglycerides

-Immunoglobulin G (Maternal antibodies)

-Drugs (high MW least likely)


Maternal Physiology-Estrogens

functions? 5

1. Enlargement of the uterus


2. Breast enlargement and growth of ductal structure


3. Enlargement of the external genitalia


4. Relaxation of pelvic ligaments


5. Affects many aspects of fetal development


Maternal Physiology-Progesterone functions


1. Induces endometrial secretory cells to decidual cells

2. Contributes to development of the conceptus before implantation, affects cell cleavage in the developing embryo

3. Inhibits myometrial contractions

4. May be involved with immune tolerance of fetus

5. Influences breasts for lactation

6. Helps develop thick mucus plug of the cervix

7. Along with estrogen changes cervix, vagina, and vulva to allow for sufficient stretching to allow delivery



What hormone rises in early pregnancy?

What hormones rise in late pregnancy? 2

1. HCG





Opathalamic changes in pregnancy? 5

(main one?)

1. Cornea thickens – may cause problems for contact lens wearers; may cause blurred vision. Pregnancy is contraindication for refractive surgery****

2. Decrease in intraocular pressure

3. Visual field changes or double vision are abnormal

4. Diabetic retinopathy may worsen dramatically during pregnancy

5. With toxemia of pregnancy, choroidal vascular insufficiency causes secondary retinal detachments


Dental Changes in Pregnancy?


1. Gingivitis of pregnancy

2. Epulis of pregnancy


Describe what the following are:

1. Gingivitis of pregnancy?

2. Epulis of pregnancy?

1. Gingivitis of pregnancy - Hormonal changes soften the tissues in mouth contributing to bleeding or inflammation.  

2. Epulis of pregnancy- a hyperplastic, granulomatous lesion.  Composed mainly of capillary vessels and endothelial proliferation. Referred to as "pregnancy tumor”.  (Similar lesions are also seen in non-pregnant individuals with dilantin therapy.)



Gastrointestinal Changes in Pregnancy


1. Relaxation of esophageal sphincter – increased incidence of GERD

2. Decreased peptic ulcer disease-due to increased mucus and decreased gastric secretion


3. Gallbladder  empties incompletely in response to meals during pregnancy

4. Delayed gastric emptying , slowed small bowel transit and decreased large bowel peristalsis – constipation, fecal impaction  (related to high progesterone)

5. Increased portal venous pressure (but not central venous pressure)

6. Nausea & vomiting (morning sickness)(nausea gravidarum) – 4 to 16 weeks

7. Hyperemesis gravidarum - persistent and severe N&V = weight loss, dehydration and electrolyte imbalances;caused by rapidly rising serum levels of  hCG and estrogen


1. Hyperemesis Gravidarum is more common in what pts? 2

2. What Rx may be required in this?

3. How can you treat Nausea & vomiting (morning sickness)(nausea gravidarum) – 4 to 16 weeks?


1. More common in a multiple pregnancy or hydatidiform mole  

2. IV fluids, antiemetics and rarely TPN may be required.

3. Vitamin B6 (Pyridoxine) 50-100 mg daily


Renal and Urinary Changes in Pregnancy


1. Progesterone relaxes bladder wall and reduces ureteral tone and peristalsis; effect may persist 12-16 wk postpartum

2. Physiological hydroureter of pregnancy – can hold 200-300 ml of urine; enlarging uterus can compress ureter at pelvic brim  (R>L)

3. Hydronephrosis is common  (R>L)

4. Changes predispose pregnant women to UTIs  and pyelonephritis


Urinary Bladder in Pregnancy

1. Enlarging uterus displaces and flattens bladder decreasing capacity; associated with what?


2. Common complaints are what? 2


1. incontinence


-increased frequency and

-nocturia. Be vigilant about evaluating for UTI