Chapter 06 Placenta and Fetal Membranes

Chapter 06  Placenta and Fetal Membranes

Complete Chapter Questions And Answers
 

Sample Questions

6. ________ Occurs only in monozygotic twins
A.
Separate placentas and membranes
B.
Fibrinoid material
C.
Amniochorionic membrane
D.
Monochorionic placenta
E.
Syncytial knot

ANS: D
A monochorionic twin placenta, associated with twins in separate amniotic sacs, occurs only with monozygotic twins; thus, this type of placenta is diagnostic of monozygotic twinning. The twins often have a common fetal-placental circulation.

7. ________ Nuclear aggregation
A.
Separate placentas and membranes
B.
Fibrinoid material
C.
Amniochorionic membrane
D.
Monochorionic placenta
E.
Syncytial knot

ANS: E
At some sites, the syncytiotrophoblast of the placental membrane in mature placentas shows protuberances or sprouts of cytoplasm that contain aggregations of syncytiotrophoblastic nuclei—syncytial knots. Some knots break off and float in the intervillous space. They may pass into the maternal circulation through the uterine veins and lodge in the capillaries of the lungs. This occurrence is not usually considered to be of clinical significance because these nuclear masses are believed to degenerate and disappear.

8. ________ Extends into cervical canal during labor
A.
Separate placentas and membranes
B.
Fibrinoid material
C.
Amniochorionic membrane
D.
Monochorionic placenta
E.
Syncytial knot

ANS: C
The chorion, with which the amnion is fused, extends into the cervical canal during the first stage of labor and helps to dilate the cervix. When the fused layers of amnion and chorion (amniochorionic membrane) rupture, the amniotic fluid escapes through the cervix and vagina.

9. ________ Forms on the surfaces of chorionic villi
A.
Separate placentas and membranes
B.
Fibrinoid material
C.
Amniochorionic membrane
D.
Monochorionic placenta
E.
Syncytial knot

ANS: B
Fibrinoid is an eosinophilic, homogeneous substance that forms on the surfaces of chorionic villi and reduces the area of tissues through which exchange of materials between the maternal and fetal circulations may take place. It consists of fibrin and other unidentified substances.