Human Anatomy & Physiology class at University of Louisiana

Sexual Reproduction (submitted by Nancy Rumore)

Males Sperm Illustration below

Testes – male gonads that lie in the scrotum
In embryonic development, the testes in in the body are found in germinal epithelium. Before birth, they descend to the scrotum through the inguinal canal. They are pulled down by the gubernacerlum to the scrotum.

Testes form because of presence of testosterone. The testes are encapsulated in tunica albuginine

There are two major parts of the testicles:
1) Testes where you will find the Seminiferous tubular part
2) Epididymis part

Path of sperm:
Seminiferous tubules is where sperm is made. Inside these tubules are Nurse (Sertole or Sustemtacular) cells. These cells nourish and push along the spermatogonia.

The seminiferous tubule:
a) join to form a straight tubule called a tubulus rectus
that
b) sends sperm into the rete testis to the efferent ductules
c) to the epididymis
d) to the ductus epididymis
e) to the vas deferens or spermatic cord.
f) sperm travels to the ampulla of the vas deferens
g) to the ejaculatory duct which is surrounded by the prostate. The prostate gland releases milky, white fluid (1/3) of semen volume.
h) The bulbourethal gland secretes a clear mucus that neutralizes urine in the urethra.
i) The seminal vesicles, located on the posterior of the bladder, secrete 60% of the seminal fluid, an alkaline based mixture.

In the spermatic cord, there are:
1) capillaries
2) lymphatic vessels
3) nerve cells

The cremaster muscle holds the testicle in place and brings it up toward the body when it is cold outside (lowers testes when it is hot). The testes must be kept cool in a hot environment and warm in a cold environment.

The prostate gland contracts muscle during ejaculation


Urethra

Conveys semen and urine.
Three regions:
1) prostatic urethra – surrounds the prostate gland - 1 - 1.5 inch
2) membraneous urethra
3) spongy penile urethra - six inches (if they are lucky) (just a joke)

Interstitial cells of Leydig make testosterone.
FSH goes to the semiferous tubules to tell them to make sperm

Penis
With the scrotum, part of the external genitalia and hang from the perineum
Penis has an attached root, shaft and the glans penis.

Corpus spongiosum surrounds the urethra and goes all the way to the root where it is called the bulb of the penis.


Production of sperm
Spermatogenesis is the formation of sperm

Website: http://www.cvm.okstate.edu/instruction/mm_curr/histology/MR/HiMRP4.htm

This website speaks at length about sperm formation

Spermatid now in the coils
-has to get excess cytoplasm removed
-undergoes huge metabolism
-acidity keeps it from moving
-don’t have to waste energy
-bulbourethral gland helps spermatids move by secreting fluid into the urethra, reducing the acidity