Question

A couple has been trying to conceive a child for over a year without success. Recently, the man’s doctor informed him that his seminal vesicles were defective. This means.
A. The man makes functional sperm but they are not delivered because he cannot ejaculate.
B. The man’s sperm lacks functional flagella.
C. The fluid needed to lubricate the man’s urethra for easier sperm travel is defective.
D. The man’s semen lacks the fructose fuel needed for the sperm to swim.

Answer 1

Hint: The seminal vesicles are a pair of sac-like glands found in the male pelvic region. Its primary function is to produce a fluid rich in fructose that gives energy to sperm, a sugar that provides nutrients to sperm cells and other proteins, enzymes, and mucus.

Complete Step by Step Answer:
Seminal vesicles are two lobulated glands found in the male pelvis. The fluid secreted from the seminal vesicles accounts for approximately 70% of the volume of the semen, or 1.5 to 2 ml of the 3 ml ejaculate volume. These secretions are essential for the proper functioning as well as the survival of sperm.
Fructose, prostaglandins, alkaline fluid, potassium, phosphorous, and coagulating proteins are all components of these secretions. Fructose gives energy to sperm. Prostaglandins are hormones that suppress the female immune system's response to sperm. Proteins form a gel-like layer on sperm, which aids in sperm coagulation. Phosphorus and potassium contribute to sperm motility. The acidic essence of the male urethra and female vagina is neutralized by alkaline fluid.
Seminal vesicle defects can cause infertility, and there are conditions that can cause the defect, one of which is dilated seminal vesicles. This condition causes partial or complete ejaculatory obstruction, with one or both ejaculatory ducts blocked. This has an impact on the volume of sperm. A transurethral ultrasound or a fructose test can be used to detect a dilated seminal vesicle. Men with this situation have low volume acidic ejaculate, oligoasthenospermia, obstructive Azoospermia, and poor progressive motility, all impacting their fertility.
The seminal vesicles' fluid high in fructose is stored in the vesicles themselves. Strong contractions occur in the muscular walls of the vesicles during ejaculation, pushing the seminal fluid into the ejaculatory ducts and urethra, where it exits the body.
Therefore, in regard to the given situation, the man’s semen lacks the fructose fuel needed for the sperm to swim.
It can be concluded that option D is correct.

Note: Azoospermia is a condition in which a man does not have sperm in his semen. It is a leading cause of male infertility. Sperm motility is required for the transport of male DNA to eggs. Flagella are made up of several proteins that help to generate and regulate motility.