Course
Module/Term
TITLE:
EXPLORE:
(4 hrs.)
HumRep (Human Reproduction)
Module 1/ Week 1-2
Anatomy and Physiology of the Male Reproductive System
INTRODUCTION:
We are going to learn about the human reproductive system,
specifically the male reproductive system. This system is composed of
external and internal organs.
Let’s get started by defining some terms:

Gonads

Gametes
Gonads - the primary reproductive gland that produces the
reproductive cells. In males the gonads are the testes while in females
the gonads are the ovaries.
Gametes - or sex cells. The gametes produced by the male parent are
called spermatozoa and female gametes are oocytes, commonly
referred to as ova or eggs.
The Male Reproductive System can be divided into 4 major parts:

Testes

Duct system

Accessory organs and

External genitalia
The Testes
Each olive-sized testis is approximately 4 cm long and 2.5 cm wide. A
fibrous connective tissue capsule, the tunica albuginea surrounds each
testis.
Extensions of this capsule (septa) plunge into the testis and divide it
into a large number of lobules.
 Each lobule contains one to four seminiferous tubules

Tightly coiled structures

Function as sperm-forming factories

Empty sperm into the rete testis
 Sperm travels through the rete testis to the epididymis

Interstitial cells produce androgens such as testosterone
During embryonic development the testes begin to descend at around 3
months.
Sometimes abnormalities can occur
The exact cause of an undescended testicle isn't known. A combination
of genetics, maternal health and other environmental factors might
disrupt the hormones, physical changes and nerve activity that
influence the development of the testicles.
The Duct System
Sperm cells pass through a series of ducts to reach the outside of the
body. After they leave the testes, the sperm passes through the
epididymis, ductus deferens and urethra.
The ductus deferens ends in the ejaculatory duct which unites with the
urethra. Cutting of the ductus deferens at the level of the testes to
prevent transportation of sperm is called Vasectomy.
The Accessory Organs
The internal organs of the male reproductive system are
called accessory organs or accessory glands. They include the paired
seminal vesicles, the single prostate gland, and the bulbourethral
(Cowper's) glands.
The mixture of sperm cells and accessory glands’ secretions is called
semen.
The Sperm cells
 The only human flagellated cells
 DNA is found in the head
The External Genitalia
The external genital structures of the male, comprising the penis and
the scrotum.
The location of the testis is a rather exposed location for a man’s testes,
which contain his entire genetic heritage, but apparently viable sperm
cannot be produced at normal body temperature. The scrotum, which
provides a temperature about 30C lower, is necessary for the
production of healthy sperm.
When the external temperature is very cold, the scrotum becomes
heavily wrinkled as it pulls the testes closer to the warmth of the body
wall. Thus, changes in scrotal surface area can maintain a temperature
that favors viable sperm production.
The penis is designed to deliver sperm into the female reproductive
tract. Internally, the spongy urethra is surrounded by three elongated
areas of erectile tissue, a spongy tissue that fills with blood during
sexual excitement. This causes the penis to enlarge and become rigid.
This event, called erection, helps the penis to serve as a penetrating
organ to deliver sperm into the female’s reproductive tract.