Which of the following disappear in umbilical cord
**Question:** Which of the following disappear in umbilical cord
A. Vasa Previa
B. Placenta
C. Fetal Membranes
D. Umbilical Cord
**Core Concept:** The umbilical cord is a vital structure that connects the fetus to the placenta in utero, facilitating nutrient and waste exchange. It contains two umbilical arteries and one vein, surrounded by Wharton's jelly.
**Why the Correct Answer is Right:** In the course of human development, the umbilical cord undergoes involution (i.e., regression or disappearance) after birth. This process is essential to prevent hemorrhage due to the sudden discontinuation of blood flow when the fetus is delivered.
**Why Each Wrong Option is Incorrect:**
A. Vasa Previa: This is a rare condition where the two umbilical arteries (vasa recta) protrude through the membranes into the amniotic cavity, increasing the risk of rupture during labor. This option is incorrect because vasa previa persists in the umbilical cord after birth, unlike the correct answer.
B. Placenta: The placenta is the primary organ responsible for fetal nutrition and waste elimination. It remains in place after birth and continues to support the fetus through the transition to extrauterine life. This option is incorrect as the placenta does not disappear in the umbilical cord.
C. Fetal Membranes: The membranes (amnion and chorion) that comprise the placenta detach from the uterine wall after birth, but they remain connected to the placenta. This option is incorrect as they do not disappear in the umbilical cord.
D. Umbilical Cord: As mentioned earlier, the umbilical cord involutes after delivery to prevent hemorrhage upon birth. This option is the correct answer because the umbilical cord disappears in the process of involution.
**Clinical Pearl:** Umbilical cord involution is a crucial aspect of normal fetal physiology, ensuring a safe transition from uterine to extrauterine life. This process is closely related to the placental separation, which occurs within minutes of birth, facilitating the fetus's adaptation to life outside the uterus.