Cord Blood Umbilical Cord 3 — Questions and Answers
Question 1: Cord blood stem cells used in transplantation are primarily derived from which cell lineage?
- Mesenchymal stromal cells
- Hematopoietic stem cells (Correct answer)
- Neural stem cells
- Endothelial progenitor cells
Correct answer: Hematopoietic stem cells
Hematopoietic stem cells (HSCs) found in cord blood are the main therapeutic cells used to reconstitute a patient's blood and immune system.
Question 2: After the umbilical cord is cut, the segment attached to the newborn dries and falls off within approximately:
- 1–3 days
- 7–21 days (Correct answer)
- 30–45 days
- 2–3 months
Correct answer: 7–21 days
The cord stump typically desiccates and separates within 7–21 days after birth.
Question 3: Which of the following best describes the blood flow direction in the umbilical arteries?
- From placenta to fetus (oxygenated)
- From fetus to placenta (deoxygenated) (Correct answer)
- Bidirectional depending on fetal heart rate
- From amniotic fluid into the fetus
Correct answer: From fetus to placenta (deoxygenated)
The two umbilical arteries carry deoxygenated, waste-laden blood from the fetus to the placenta for exchange.
Question 4: What is the average length of the umbilical cord at term?
- 20–30 cm
- 30–40 cm
- 50–60 cm (Correct answer)
- 70–80 cm
Correct answer: 50–60 cm
The average term umbilical cord measures approximately 50–60 cm in length.
Question 5: An unusually short umbilical cord (less than 35 cm) may be associated with which complication during delivery?
- Premature rupture of membranes
- Placental abruption at delivery (Correct answer)
- Excessive fetal movement
- Maternal hypertension
Correct answer: Placental abruption at delivery
A short cord can cause traction on the placenta during fetal descent, leading to placental abruption or cord rupture.
Question 6: What is a true knot in the umbilical cord?
- A tight loop of cord around the fetal wrist
- An actual knot formed when the fetus passes through a loop of cord (Correct answer)
- A segment where Wharton's jelly is absent
- A surgical tie placed by the obstetrician
Correct answer: An actual knot formed when the fetus passes through a loop of cord
True knots form when the fetus slips through a loop of cord in utero, and they can restrict blood flow if pulled tight.
Question 7: Which characteristic of cord blood makes it more immunologically tolerant than bone marrow for transplantation?
- Higher red blood cell count
- More naive, immature T-lymphocytes (Correct answer)
- Absence of hematopoietic stem cells
- Higher concentration of platelets
Correct answer: More naive, immature T-lymphocytes
Cord blood contains more naive, less reactive T-lymphocytes, reducing the risk of graft-versus-host disease (GvHD) compared to adult bone marrow.
Cord Blood Umbilical Cord 3
Cord blood stem cells used in transplantation are primarily derived from which cell lineage?