Oxygenated blood to the fetus is carried by-
**Core Concept**
The transfer of oxygen and nutrients from the mother to the fetus occurs through a complex process involving the placenta, a vital organ that develops in the uterus during pregnancy. The exchange of gases, nutrients, and waste products between the maternal and fetal circulations is facilitated by the unique characteristics of the placental structure.
**Why the Correct Answer is Right**
Oxygenated blood from the mother is carried to the fetus through the umbilical arteries, which branch off from the maternal internal iliac arteries. The oxygenated blood then enters the placenta, where it is exchanged for deoxygenated blood from the fetus. This exchange occurs in the placental villi, which are tiny, finger-like projections that increase the surface area for gas and nutrient exchange. The oxygenated blood is then carried back to the fetus through the umbilical veins, specifically the **umbilical vein of Wharton**. This vein is a key structure responsible for carrying oxygenated blood from the placenta to the fetus.
**Why Each Wrong Option is Incorrect**
**Option A:** This is not a correct description of the structure responsible for carrying oxygenated blood to the fetus.
**Option B:** While the placenta is indeed the site of gas exchange between the mother and fetus, it is not the specific structure responsible for carrying oxygenated blood to the fetus.
**Option D:** This is not a correct description of the structure responsible for carrying oxygenated blood to the fetus.
**Clinical Pearl / High-Yield Fact**
The umbilical vein of Wharton is a vital structure that carries oxygenated blood from the placenta to the fetus. This vein is a key landmark during fetal surgery and is often used as a reference point for identifying the fetal bladder.
**Correct Answer:** C.