**Question:** The umbilical cord in a full term infant contains:

A. Arteries
B. Veins
C. Nerve fibers
D. Air

**Core Concept:** The umbilical cord is a vital structure connecting the fetus to the placenta during pregnancy, supplying essential nutrients, oxygen, and waste removal. In a full-term infant, the cord contains blood vessels and other structures.

**Why the Correct Answer is Right:** The umbilical cord contains two main blood vessels: the umbilical artery and the umbilical vein. The artery carries deoxygenated blood from the fetus to the placenta, while the vein carries oxygenated blood from the placenta back to the fetus. This ensures efficient exchange of gases and nutrients between the mother and the fetus.

**Why Each Wrong Option is Incorrect:**

A. Arteries (Option A) and veins (Option B) are the correct vessels in the umbilical cord. Arteries transport deoxygenated blood, while veins transport oxygenated blood, facilitating gas and nutrient exchange.

C. Nerve fibers (Option C) are not present in the umbilical cord. The cord primarily consists of blood vessels and connective tissue to support their functions.

D. Air (Option D) does not belong in the umbilical cord, as it is a gas-filled space and not a component of the cord.

**Clinical Pearl:** Understanding the anatomy of the umbilical cord is essential for healthcare professionals, as it helps in interpreting any complications during labor or neonatal resuscitation. A newborn's color can provide useful clues about umbilical cord conditions, such as cyanosis (bluish discoloration) indicating low oxygen levels, or meconium-stained amniotic fluid, which could be related to umbilical cord issues.

**Correct Answer:** B. Umbilical vein

The umbilical vein is the correct answer because it carries oxygenated blood from the fetus back to the placenta, ensuring efficient gas and nutrient exchange between the mother and fetus.