placenta SC

Question 1

PLACENTA is a _______ organ that forms during pregnancy and serves the following FUNCTIONS:

Acts as an organ of _____ between maternal and fetal tissues, providing ______, ______, and _____ for the fetus.

The placenta produces the following hormones:

1.

2.

3.

Finally, the placenta Serves as an ______ ______ between maternal and fetal tissues

Answer 1

fetal-maternal

exchange

Nutrition, respiration, and excretion

1. Progesterone
2. hCG=human chorionic gonadotropin
3. human placental lactogen=somatomammotropin

immunological barrier

Question 2

The placenta develops as the _____ (the _____ component) of the uterus is invaded by the embryo’s trophoblast which forms _____ ____ (the _____ component)

Answer 2

endometrium

maternal

chorionic villi

fetal

Question 3

Human placenta is hemochorial which means?

Answer 3

maternal blood comes in direct contact with the chorion

Question 4

What is the endometrium located at the implantation site called?

Answer 4

decidua basalis

Question 5

The fetal surface of the placenta is characterized by the vascular _____ ____ covered by amnion, giving it a smooth, shiny grayish appearance, and the eccentrically attached _____ ____ that has 2 umbilical ______ and 1 umbilical _____ that are surrounded by _____ connective tissue called ____ ____.

Answer 5

• chorionic plate
• amnion
• umbillical
• arteries
• vein
• mucous CT
• Wharton’s jelly

Question 6

Umbilical vessels are _____ than the umbilical cord so they commonly twist around each other and sometimes ____ to form ____ known as ____ __.

Answer 6

longer

bend

loops

false knots

Question 7

The decidua is the ______ of the uterus in a pregnant woman. The three regions of the decidua are named according to their relation to the implantation site.

• The ______ _____ is the part of the decidua deep to the ______ (embryo and membranes) that forms the maternal part of the placenta
• The ____ ____is the superficial part of the decidua overlying the conceptus.
• The _______ _____ is all the remaining parts of the decidua.

Answer 7

endometrium

decidua basalis

conceptus

decidua capsularis

decidua parietalis

Question 8

What is the conceptus?

Answer 8

The embryo and membranes

Question 9

What gives the maternal side of the placenta a cobblestone appearance? What are these separated by?

Answer 9

15-20 compartments, called cotyledons

placental septa

Question 10

The fetal component of the placenta is derived from the _____ and the ______ _____, forming the ______ _____.

Answer 10

Trophoblast

extraembryonic mesoderm

villous chorion

Question 11

During week 2, _____ _____ form within the synctiotrophoblast. ____ _____ near the synctiotrophoblast expand to form _____ _____ which ______ with the lacunae, filling them with blood. This process initiates the _____ ____ ____.

As these anastomoses develop, the cytotrophoblast initiates the formation of ____ _____.

Answer 11

Trophoblastic lacunae

Maternal capillaries

maternal sinusoids

anastomose

maternal fetal circulation

chorionic villi

Question 12

The blood vessels formed in the tertiary villi make contact with capillaries that develop in the ____ ____ and ____ _____,which establish contact with the _____ _____. The cytotrophoblast cells in the ____ penetrate through the _____ _____ until they reach the _____. Here they contact similar extensions from neighboring villi and form the _____ ______.

Answer 12

chorionic plate

connecting stalk

embryonic circulation

villi

syncytiotrophoblast covering

decidua

cytotrophoblast shell

Question 13

The cytotrophoblast shell:

1. Firmly attaches the _____ to the ______
2. Is perforated by _____ _____ to supply and drain _____ from ______ ______.
3. Degenerates by term and is replaced by _____ _____

Answer 13

chorion to the endometrium

maternal vessels

blood from intervillous spaces

fibrinoid material

Question 14

_____ _____ (______ ____)are those that extend from the chorionic plate to the decidua basalis (____ ____). ____ ____ will branch from the side of anchoring villi and represent sites where the _____ and ___ _____will occur between maternal and fetal blood.

Answer 14

• Stem villi (anchoring villi)
• decidual plate
• Terminal villi
• nutrient and gas exchange

Question 15

The intervillous space of the placenta contains ____ ___

Answer 15

maternal blood

Question 16

The placental membrane separates the _____ ____ from ____ ____. Think about it as the barrier that separates the maternal and fetal circulation; it is not an actual “membrane”. Its structure changes throughout pregnancy.

Initially (by month 4), the outer surface of the ____ ___form a placental membrane that consists of 4 layers:

1.

2.

3.

4.

By the beginning of month 4, the ________ degenerates, leaving only 2 layers in the placental membrane:

1.

2.

Answer 16

maternal blood from fetal blood

terminal villi

1. Syncytiotrophoblast
2. Cytotrophoblast
3. Extraembryonic mesoderm
4. Fetal endothelium

cytotrophoblast

1. Syncytiotrophoblast
2. Fetal endothelium

Question 17

In the third trimester, the syncytiotrophoblast becomes very _____. Large pieces of it containing _____ ___ may break off as ____ ____ and enter the ____ _____; these enter the maternal circulation and are broken down in _____.

Answer 17

thin

several nuclei

as synctial knots

intervillous spaces

lungs

Question 18

Prior to week 8, ___ cover the entire surface of the chorion. As the pregnancy advances, however, chorionic villi on the _____ _____ continue to _____ to form the_____ _____ (___ ____). Chorionic villi on the _____ _____ degenerate and form a _____ _____ _____ by the end of month 3.

Answer 18

villi

embryonic pole

proliferate

chorionic frondosum (bushy chorion)

ab-embryonic pole

smooth chorionic laeve

Question 19

Clinical correlate: ____ ____ ____ is a ____ ____ (that occurs ______ or _________) of chorionic villus tissue for genetic testing and is performed around weeks ____

Answer 19

Chorionic villus sampling

needle aspiration

transabdominal or transvaginal

10-12

Question 20

During the 2nd week the _____ ____ appears on day 8 as fluid begins to collect between cells of the____ and overlying ____.

A layer of ____cells expands toward the embryonic pole and differentiates into a____ ____ separating the new cavity from the _______. This membrane is the lining of the amnion. Although the amniotic cavity is at first smaller than the _____ _____, it expands steadily.

By the ___ week, the amnion encloses the ____ ____.

The amnion becomes continuous with ___ at the attachment of the umbilical cord to the fetus (_____ ___ ___) and covers _____ _____ and _____.

Answer 20

amniotic cavity

epiblast and trophoblast

epiblast

thin membrane

cytotrophoblast

blastocyst cavity

8th

entire embryo

skin

primitive umbilical ring

umbilical cord and placenta

Question 21

Initially, amniotic fluid is secreted by cells of the____and some is derived from maternal ____, ____, and _____ ____ by diffusion. Beginning in the 11th week, the____contributes to the amniotic fluid by excreting ____ into the amniotic cavity. By late pregnancy, approximately ___ of fetal urine is added daily. Volume increases throughout pregnancy

30 mL at 10 weeks; 1000 mL at 37 weeks

Answer 21

amnion

maternal blood, tissue and interstitial fluid

fetus

urine

500 ml

Question 22

AMNIOTIC FLUID CIRCULATION:

Amniotic fluid is _____ by the fetus and absorbed by the fetus’s_______ and ______ ____. The fluid passes into the ____ _____ and the waste products in it cross the ____ _____ and enter the maternal blood in the _____ ____. Excess water in the fetal blood is excreted by the ____ _____ and returned to the amniotic sac through the____ ____ ____-.

Answer 22

swallowed

respiratory and digestive tracts

fetal bloodstream

placental membrane

intervillous space.

fetal kidneys

fetal urinary tract.

Question 23

As the volume of amnionic fluid increases, the amnion is pushed against the chorion and the ____ _____is obliterated such that the amnion lies against the ___ ____ to form the ______-_____ _____ (this is the “water-bag” that breaks prior to the delivery of the baby)

Answer 23

chorionic cavity

chorionic laeve

amnio-chorionic membrane

Question 24

What are the functions of the amnionic fluid (5)?

Answer 24

Allows for fetal movements

Prevents adherence between amnion and embryo

Shock absorber

Barrier to infection

Promotes lung development

Question 25

What is amniocentesis? describe the process

Answer 25

a tyoe of analysis in which in a hollow needle is inserted through the mothers abdomen to the uterus and amniotic fluid is taken for analysis.

Question 26

What is Amniotic bands/constriction ring syndrome?

Answer 26

Tears in the amnion may result in amniotic bands that encircle the fetal limbs or digits resulting in deformations

Question 27

______ is the term for excess amniotic fluid. This is correlated with _____ _____ and disorders of _____ ____ _____ and _____ ______ (various atresias) that prevent the fetus from _______ amniotic fluid.

Answer 27

Polyhydramnios

maternal diabetes

CNS

GI tract

swallowing

Question 28

______ is too little amniotic fluid; may result from failure of the ____ ____ to form or amniotic fluid_____. Severe oligohydramnios early in pregnancy is a risk factor for ____ _______.

Answer 28

Oligohydramnios:

fetal kidneys

leakage

lung hypoplasia (lung underdevelopment)

Question 29

Maternally derived cholesterol, triglycerides, phospholipids, ans Protein hormones like insulin, IgD, IgE, IgM ___ ___ cross the placenta

Answer 29

DO NOT