Umbilical cord has –
First, the core concept here is the anatomy of the umbilical cord. I remember that the umbilical cord connects the fetus to the placenta and is crucial for nutrient and waste exchange. It contains blood vessels, specifically two arteries and one vein. The structure also includes Wharton's jelly, which provides a protective matrix around the vessels.
Now, the correct answer should mention the two arteries and one vein. Let's say the options were about the number of vessels. The correct answer would be two arteries and one vein. The other options might have the numbers reversed or include incorrect structures like three vessels without specifying types, or mention other components like the umbilical vein being two.
For the incorrect options, if an option states three vessels, that's wrong because there are two arteries and one vein. If another option mentions only one artery and one vein, that's incorrect. Also, if an option lists the umbilical cord having a vein and two arteries but reverses the numbers, that's a possible distractor. Another common mistake is confusing the umbilical cord's vessels with those in the placenta.
The clinical pearl here is to remember the "2A1V" mnemonic for the umbilical cord's vessels. This is a high-yield fact for exams like NEET and USMLE. Also, knowing that the umbilical vein carries oxygenated blood from the placenta to the fetus, while the arteries return deoxygenated blood and waste.
Putting it all together, the correct answer should state that the umbilical cord has two arteries and one vein. The explanation needs to cover the structure, the role of Wharton's jelly, and the direction of blood flow. The incorrect options are addressed by pointing out the common errors in vessel count and their roles.
**Core Concept** The umbilical cord is a vital fetal-placental connection containing blood vessels and connective tissue. It transmits oxygenated blood from the placenta via the single umbilical vein and returns deoxygenated blood via two umbilical arteries. Wharton’s jelly provides structural support and prevents vessel kinking.
**Why the Correct Answer is Right** The umbilical cord contains **two arteries and one vein**. The vein (umbilical vein) carries oxygen-rich blood from the placenta to the fetus, while the arteries return deoxygenated blood and fetal waste to the placenta. These vessels are surrounded by Wharton’s jelly, a mucoid connective tissue that maintains patency and prevents compression. The 2:1 ratio of arteries to vein is critical for efficient fetal-placental circulation.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect if it states "one artery and one vein"—this ignores the dual arterial supply essential for waste removal.
**Option B:** Incorrect if it claims "three arteries"—there are only two umbilical arteries in the cord.
**Option C:** Incorrect if it describes "vein and two arteries but reversed"—confusing artery/vein roles reverses their physiological functions.
**Option D:** Incorrect if it lists "no Wharton’s jelly