Fertilization of the ovum usually occurs at:

Appeared in: DSSSB 6 September 2024

Explanation

The ampulla is the longest and widest portion of the fallopian tube, making up about two-thirds of its length.
This anatomical structure provides an optimal environment for the sperm to meet the ovum after it is captured by the fimbriae.
Fertilization, the fusion of the sperm and egg, occurs in the ampulla.
Following fertilization, the resulting zygote travels through the remainder of the tube (isthmus and intramural part) to the uterus for implantation.

Option A: This is an anatomically nonexistent structure. The clitoris is an external genital organ, completely separate from the internal fallopian tubes.
Option B: The isthmus is the narrow segment of the fallopian tube that connects to the uterus. Its primary function is to transport the fertilized egg to the uterus, not to be the site of fertilization.
Option D: The fimbriae are finger-like projections at the ovarian end of the fallopian tube. Their function is to sweep the ovulated egg from the surface of the ovary into the tube.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomy and physiology of the female reproductive system, specifically the site of fertilization as background academic context rather than a clinical decision trigger.
Understanding the site of fertilization is crucial for diagnosing and managing ectopic pregnancies. An ectopic pregnancy occurs when the fertilized egg implants outside the uterus, most commonly in the ampulla of the fallopian tube.
Knowledge of fallopian tube anatomy is essential for female sterilization procedures (tubal ligation or tubectomy), where the tubes are blocked or cut to prevent sperm from reaching the egg.
Infertility investigations, such as a hysterosalpingogram (HSG), assess the patency (openness) of the fallopian tubes, as blockages can prevent fertilization.

How to Approach the Question

First, identify the core of the question, which is asking for the specific location of fertilization within the female reproductive tract.
Recall the major parts of the fallopian tube: fimbriae, infundibulum, ampulla, and isthmus.
Consider the function of each part in the process of reproduction.
Eliminate anatomically incorrect options, such as 'Clitoris of the fallopian tube'.
Differentiate the functions of the remaining parts: Fimbriae capture the egg, the isthmus transports it to the uterus, and the ampulla is the site where fertilization occurs.
Select the option that correctly identifies the primary site of fertilization.

Concept Tested & Keywords

Concept Tested: Anatomy and physiology of the female reproductive system, specifically the site of fertilization.
Stem keywords: Fertilization, ovum, fallopian tube
Lead-in keywords: occurs at

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E6 Anatomy Applied Ashalatha 4e p. 389-391

E6 Physiology Ganong 27e Vol 2 Part 3 p. 150-151

E6 Physiology Guyton 4SAE Part 3 p. 50-52

Practise the full DSSSB 6 September 2024

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