Human Reproduction ❮ 201
excessively detailed and not something you should get hung up on. You will want to know
some details about development, but like glycolysis, the big picture is key. The AP Biology
exam is not an embryology exam. Finally, the chapter concludes with a discussion of hor-
mones and their effects on the reproductive system.
Sex Differences
What are the biologic differences between a man and a woman? For the purposes of this
exam, you should keep in mind that one of the first distinctions is that boys have a Y chro-
mosome in the nuclei of their cells, and girls do not. Another major difference lies in the sex
characteristics.Primary sex characteristicsare the structures that assist in the vital process
of procreation. Among these are the testes, ovaries, and uterus. Secondary sex characteris-
ticsare the noticeable physical characteristics that differ between males and females such as
facial hair, deepness of voice, breasts, and muscle distribution. These characteristics come
into play as indicators of reproductive maturity to those of the opposite sex.
Anatomy
Since males tend to be a bit impatient, we will cover male anatomy first. The male sexual
anatomy is designed for the delivery of sperm to the female reproductive system. Let’s
follow the journey of a sperm from the beginning to the end.
Sperm’s “Wild Ride”
Here we stand in the testis.The male has two testes, located in a sac called the scrotum.
This is the sperm factory—a portion of the testis called the seminiferous tubulesis where
the sperm are actually made. We return later to look at how these sperm are created. Notice
in the other corner of the testis the structures called the interstitial cells.These are the
structures that produce the hormones involved in the male reproductive system. Remember
that the testis is the site of sperm and hormone production in the male reproductive system.
We are going to move along the production line to the epididymis—the coiled structure
that extends from the testes. The epididymis is where the sperm completes its maturation and
waits until it is called on to do its duty. From here, when called into action, the sperm moves
through a tunnel called the vas deferens.Each epididymis connects to the urethravia this
tunnel. The urethra is the passageway through which the sperm exits during ejaculation. Yes...
that is indeed the same tunnel that the urine uses to get out... good observation in back.
We’re not done yet—let’s look at some other important players in this process (see also
Figure 16.1). we are sure you have all heard about the prostate glandand how prostate
cancer is currently one of the major cancers among men. But do you know what the prostate
gland does? Here we are standing by this fine structure whose function in the male repro-
ductive system is to add a basic (pH > 7) liquid to the mix to help neutralize any urine that
may remain in the common urethral passage. It also helps to combat the acidity of the vagi-
nal region of the female toward which the sperm is heading.
Follow us, everyone, more to see, more to see.... Here, on either side of us, are the struc-
tures called the seminal vesicles.These characters play an important role in the success of the
sperm on its way to the female ovum. When the male ejaculates, the seminal vesicles dump
fluids into the vas deferens to send along with the sperm. Think of the seminal vesicle as a con-
venience store. It provides three important goods to the sperm: energy by adding fructose;
power to progress through the female reproductive system by adding prostaglandins(which
stimulates uterine contraction); and mucus, which helps the sperm swim more effectively.
http://www.ebook3000.com
