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Chapter 16. Male Reproductive System

Refer to the micrograph below to answer the following question. The lower panel of the micrograph shows a small region of the organ at high magnification.

Image not available.

After reviewing a biopsy specimen, the pathologist diagnoses the tumor as originating from the cells labeled A. Which of the following substances would most likely be secreted by the cells in this tumor?

A. Androgen-binding protein

B. Cortisol

C. Estradiol

D. Fructose

E. Testosterone

The answer is E: The cells labeled A in the micrograph are Leydig cells in the interstitium between the seminiferous tubules of the testis. Leydig cells normally synthesize and release the androgen testosterone.

Refer to the micrograph below to answer the following question. The lower panel of the micrograph shows a small region of the organ at high magnification.

Image not available.

Which letter designates the type of cell that forms the blood-testis barrier?

A. A

B. B

C. C

D. D

E. E

The answer is C: The cell labeled C is a Sertoli cell, a nonproliferating support cell in the seminiferous epithelium of the testis. Tight junctions between Sertoli cells form the blood-testis barrier, which prevents sperm-specific antigens from entering the blood and becoming immunogens, and prevents circulating antibodies from entering the tubule lumen. Sertoli cells also secrete a fructose-rich fluid that nourishes developing sperm and facilitates transport of sperm to the genital ducts, androgen-binding, which binds testosterone and increases the concentration of testosterone in the tubule lumen, and inhibin and activin.

Which organ listed below produces a fructose-rich fluid that comprises almost all of the ejaculate?

A. Bulbourethral gland

B. Epididymis

C. Prostate gland

D. Seminal vesicle

E. Seminiferous tubules

The answer is D: The seminal vesicles are two highly convoluted, unbranched tubules that secrete a thick, creamy fluid that comprises 70–80% of the ejaculate. The secretions contain a high concentration of fructose, which provides an energy source for sperm and nourishes sperm within the female reproductive tract.

Arrange in order the following structures and organs that a spermatozoon passes through ...

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