What is semen?

Appeared in: P.CHO-2019

Explanation

Semen is a composite fluid, not a single substance, that is ejaculated during the male sexual act.
It contains spermatozoa (sperms) from the testes, which are the male reproductive cells.
It also contains seminal plasma, which is a mixture of secretions from accessory glands including the seminal vesicles (seminal fluid) and the prostate gland (prostatic fluid).
Since prostatic fluid, sperms, and seminal fluid are all essential components of semen, the option 'All of the above' is the only complete and correct answer.

Option A: Prostatic fluid is only one component of semen, contributing about 30% of the total volume. It is not the entirety of semen.
Option B: Sperms are the cellular component of semen but make up only about 10% of the volume. The majority of semen is fluid.
Option C: Seminal fluid, secreted by the seminal vesicles, is the largest single contributor to semen volume (about 60%), but it is still only one part of the whole.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Composition of Semen as background academic context rather than a clinical decision trigger.
Understanding the composition of semen is crucial for performing and interpreting a semen analysis, a key test in the evaluation of male infertility.
Abnormalities in specific components can point to underlying pathologies. For instance, a low volume of ejaculate with an acidic pH and no fructose may indicate an obstruction of the ejaculatory ducts or congenital absence of the seminal vesicles.
Azoospermia (absence of sperm) can be obstructive (a blockage) or non-obstructive (testicular failure), which requires different management strategies.

How to Approach the Question

Step 1: Identify the core of the question, which is to define or describe the composition of 'semen'.
Step 2: Recall the basic biological knowledge about male reproduction. Semen is the fluid that is ejaculated.
Step 3: Consider each of the first three options: 'Prostatic Fluid', 'Sperms', and 'Seminal Fluid'. Recognize that all three are related to male reproduction.
Step 4: Synthesize this knowledge. Semen is not a single substance but a mixture. It contains sperm cells suspended in fluids from various glands.
Step 5: Evaluate the final option, 'All of the above'. Since the first three options are all known components of semen, this collective option is the most comprehensive and accurate answer.

Concept Tested & Keywords

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E6 Physiology Essentials Sembulingam 10e Part 2 p. 111-113

E6 Physiology Guyton 4SAE Part 3 p. 20-22

E6 Gynecology Williams p. 23-51

Practise the full P.CHO-2019

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