Question

1.) Trace the path of sperm development and its passage from the testis through the
epididymis, vas deferens, and out the urethra. Be sure to name all the accessory
gland and contributions to the formation of semen as you do so.

2.) Answer the following questions:

a) Why do you suppose males produce so many millions of sperm with each
ejaculation?

b) Note that the vas deferens (also called ductus deferens) is a tube nearly 30
cm (12 inches) in length! Why should it be so long? Can you imagine a
“shortcut” that would make it shorter and perhaps more efficient?

c) Does it seem strange to you that the urethra from the urinary bladder joins
the ejaculatory duct and then creates one tube (the prostatic urethra and
the penile urethra) that at times carries urine and at other times carries
semen? Does this seem like bad plumbing to you? Explain your thoughts.

3) Outline the basic glands and tubes involved in female reproduction. Outline the
process of ovulation, discussing all the major structures involved and their
functions.

4) Observe the location of the bladder and uterus. Why do you suppose that the
uterus lies above not under the bladder? (Hint: think of walking “on all fours.”
What would be the position of the uterus if that were true, as it is for most other
mammals?)

5) Explain why virtually all of the female reproductive organs, even the prostate
tissue, have homologous counterparts in males.

6) Explain the difference between asexual reproduction and sexual reproduction.
Which method provides for the greatest genetic diversity in the offspring? Explain
why this is so.

7) Compare the basic steps of meiosis in oogenesis and spermatogenesis. Which
method produces the greatest number of gametes? Explain why this is so.

Answer 1

1. Ans- The male reproductive system includes a pair of testes, alongwith accessory ducts, glands includes rete testis, vasa efferentia and epididymis and vas deferens.

In testis, the immature male germ cells produce sperms by spermatogenesis that begins at puberty. The way sperm development starts with spermatogonia present on the inside wall of seminiferous tubules multiplied by mitotic division and increase in numbers. Each spermatogonium is diploid and contains 46 chromosomes. Some of the spermatogonia periodically undergo meiosis called primary spermatocytes. A primary spermatocyte completes the reduction division leading to formation of two equal, haploid cells called secondary spermatocytes, which have only 23 chromosomes each. The secondary spermatocytes undergo the second meiotic division to produce 4 equal, haploid spermatids. The spermatids are transformed into spermatozoa that is sperms by the process called spermiogenesis.

There is a system of tiny tubes in the testicles. These tubes , called the seminiferous tubules, house the germ cells that hormones including testosterone, the male sex hormone cause to turn into sperm. The germ cells divide and change untill they resemble tadpoles with a head and a short tail. The tails push the sperm into a tube behind the testes called the epididymis, completing their development . Once out of the epididymis , the sperm move to the vas deferens. When a man is stimulated for sexual activity, the sperm are mixed with seminal fluid, a whitish liquid produced by seminal vesicles and the prostate gland to from semen. The seminal plasma along with the sperms constitute the semen. As a result of the stimulation, the semen , which contains upto 500 million sperm, is pushed out of the male sex organ(ejaculated) through the urethra. The male accessory ducts play an important role in the motility , temporary storage of sperms and transport the sperms from the testes to the outside through the urethra. The urethra originates from the urinary bladder and extends through the male sex organ to its external opening called urethral meatus.

The path showing sperm development by the process spermatogenesis is shown below for better understanding.

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