The fertilized egg is known as?

Appeared in: SGPGI Nursing Officer-2023

Explanation

A zygote is the single diploid cell formed by the fusion of a sperm and an ovum during fertilization.
It contains the complete set of 46 chromosomes, with 23 from the maternal ovum and 23 from the paternal sperm.
This initial cell marks the beginning of embryonic development and undergoes rapid cell division (cleavage) to form a morula and then a blastocyst.

Option A: An egg, or ovum, is an unfertilized female reproductive cell (gamete).
Option B: The term embryo refers to a later stage of development, typically from the time of implantation in the uterus (around week 3) until the 8th week of gestation.
Option C: A gamete is a general term for a mature reproductive cell, such as a sperm or an egg.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Terminology of early human development after fertilization as background academic context rather than a clinical decision trigger.
Understanding the precise terminology of early development is fundamental in obstetrics, fertility treatments (like IVF), and genetic counseling.
The viability of the zygote and its successful development into a blastocyst are critical milestones assessed during in vitro fertilization (IVF) procedures before embryo transfer.
What if? If the question asked for the stage that implants into the uterine wall, the answer would be the blastocyst, which is the stage of development approximately 5-7 days after fertilization.

How to Approach the Question

This is a factual recall question that tests knowledge of basic embryology terms.
First, identify the key term in the question: 'fertilized egg'.
Recall the sequence of early human development: Gametes (sperm and egg) fuse during fertilization to create a zygote.
The zygote divides to become a morula, then a blastocyst, which implants and develops into an embryo, and finally a fetus.
Evaluate each option against this sequence. 'Zygote' is the specific term for the single cell immediately following fertilization.

Concept Tested & Keywords

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E6 Obstetrics Williams p. 63-85

E6 Midwifery Obstetrics and Gynecology Nursing Sandeep Kaur p. 48-56

Practise the full SGPGI Nursing Officer-2023

Attempt every question from this paper in a timed mock, then review the full solution for each one.