Placenta And Some Of IT's Functions

1. The stage of labour when the placenta is birthed is known as:

First stage of labour

Second stage of labour

Third stage of labour

Fourth stage of labour

First stage of labour is from the onset of contractions to the full dilatation of the cervix (10cm)
Second stage of labour is from full dilatation of the cervix to the birth of the baby
Third stage of labour is from the birth of the baby to the birth of the placenta
Fourth stage of labour is the immediate period following birth of the placenta till transfer to postnatal facility

Explanation

First stage of labour is from the onset of contractions to the full dilatation of the cervix (10cm)
Second stage of labour is from full dilatation of the cervix to the birth of the baby
Third stage of labour is from the birth of the baby to the birth of the placenta
Fourth stage of labour is the immediate period following birth of the placenta till transfer to postnatal facility

2. Deoxygenated blood from the baby to the placenta is carried by:

One umbilical artery

Two umbilical arteries

One umbilical vein

Two umbilical veins

Just as in pulmonary circulation the de-oxygenated blood is carried by pulmonary arteries from the heart to the lungs the same is true of umbilical arteries - carrying de-oxygenated blood from the baby to the placenta

Explanation

Just as in pulmonary circulation the de-oxygenated blood is carried by pulmonary arteries from the heart to the lungs the same is true of umbilical arteries - carrying de-oxygenated blood from the baby to the placenta

3. Oxygenated blood from the placenta to the baby is carried by:

One umbilical artery

Two umbilical arteries

One umbilical vein

Two umbilical veins

The veins usually carry deoxygenated blood however in pulmonary circulation (Pulmonary veins) and in the umbilical vein it is oxygenated blood that is carried by the vein and de-oxygenated blood by the pulmonary arteries and umbilical arteries.

Explanation

The veins usually carry deoxygenated blood however in pulmonary circulation (Pulmonary veins) and in the umbilical vein it is oxygenated blood that is carried by the vein and de-oxygenated blood by the pulmonary arteries and umbilical arteries.

4. Which cells of the blastocyst need to invade the endometrium for the placenta to form?

Ectoderm

Mesoderm

Inner cell mass

Syncitiotrophoblast

Syncitiotrophoblast is the outer layer of trophoblast that invades the uterine decidua for the placenta to form

Explanation

Syncitiotrophoblast is the outer layer of trophoblast that invades the uterine decidua for the placenta to form

5. The main hormone produced by the placenta that sustains the pregnancy is:

Oestrogen

Beta Human Chorionic Gonadotrophin

Progesterone

Human Placental Lactogen

Progesterone is the hormone that ensure the continuation of pregnancy.

Explanation

Progesterone is the hormone that ensure the continuation of pregnancy.

6. The cord should be clamped and cut immediately after the birth of the baby:

True as it causes jaundice in the baby always requiring treatment

Clamping and cutting the cord is only delayed in preterm infants

True as it has no role in adaptation for the baby

Delayed clamping & cutting aids with adaptation for the baby

Evidence suggests that if the baby is vigorous at birth it may be beneficial to delay cord clamping & cutting until cord has stopped pulsating. See the video clip of Delayed cord clamping under "Video Clips" in Information of this site

Explanation

Evidence suggests that if the baby is vigorous at birth it may be beneficial to delay cord clamping & cutting until cord has stopped pulsating. See the video clip of Delayed cord clamping under "Video Clips" in Information of this site

7. The placenta has two membranes - Chorion and the amnion. Which cells are responsible for forming these two membranes?

Chorion is formed by the migrating ectoderm from the embryonic disc while amnion is formed by the cytotrophoblast

Chorion is formed by the cytotrophoblast while the amnion is formed by the migrating ectoderm from the embryonic disc

Both membranes are formed by the cytotrophoblast

Both membranes are formed by the migrating ectoderm from the embryonic disc

Cytotrophoblast forms the outer membrane the chorion while the migrating ectoderm from the embryonic disc forms the inner amnion

Explanation

Cytotrophoblast forms the outer membrane the chorion while the migrating ectoderm from the embryonic disc forms the inner amnion

8. The placenta and the baby evade attack from the mother's immune system by:

Producing Neurokinin B from the placenta & Lymphocyte Suppressor cells by the baby

Producing Neurokinin B by the baby

Producing Lymphocyte suppressor cells by the placenta & the baby

Producing Neurokinin B by the placenta & the baby

The placenta functions as a major immunological barrier (production of Neurokinin B one example) and the Lymphocyte suppressors are produced by the baby to ensure the pregnancy is not rejected.

Explanation

The placenta functions as a major immunological barrier (production of Neurokinin B one example) and the Lymphocyte suppressors are produced by the baby to ensure the pregnancy is not rejected.

9. The blood flow through the placent at term is:

200-300l/min

400-500l/min

600-700l/min

800-900l/min

By term (37-42 weeks of pregnancy) the amount of blood flow in the placenta every minute is 600-700l.

Explanation

By term (37-42 weeks of pregnancy) the amount of blood flow in the placenta every minute is 600-700l.

10. The uterotonic agent that may be used to actively manage the birth of the placenta is:

Syntocinon 5IU IV

Syntocinon 10IU IV

Syntometrine 1ml IV

Depends on the woman's preference

You can use Syntocinon 10IU and Syntometrine 1ml but these should be administered intramuscularly and NOT intravenously. The woman's preference is important in relation to having the uterotonic agent and the route of administration however the decision has been made to actively manage and the only route offered in the response is IV so the safest response is Syntocinon 5IU IV

Explanation

You can use Syntocinon 10IU and Syntometrine 1ml but these should be administered intramuscularly and NOT intravenously. The woman's preference is important in relation to having the uterotonic agent and the route of administration however the decision has been made to actively manage and the only route offered in the response is IV so the safest response is Syntocinon 5IU IV