1. The Reproductive Systems
Chapter 28
The Reproductive Systems

2. Reproduction Overview
Sexual Reproduction is the process in which organisms produce offspring by means of uniting gametes (sperm and egg)
Male reproductive organs secrete androgen hormones, produce gametes (sperm), and facilitate fertilization
Female reproductive organs secrete female hormones, produce gametes (ova), facilitate fertilization and sustain growth of the embryo and fetus

3. Reproduction Overview
Urology is the medical specialty that treats disorders and diseases of the male reproductive system
Gynecology is the medical specialty that treats disorders and diseases of the female reproductive system
Obstetrics focuses on the care of women during pregnancy

4. Male Reproductive Anatomy
The genitals are all the structures of reproduction
The gonads (the testes in males and ovaries in females) are the site for gamete production and hormone secretion
Various ducts store and transport gametes
Accessory sex glands produce secretions to protect and support the gametes
Supporting structures deliver and/or assist in joining gametes (penis in male, vagina and uterus in female)

5. Male Reproductive Anatomy
The male gonads are the testes (singular: testis)
The ducts of the male reproductive system are the:
vas deferens (ductus deferens)
ejaculatory ducts
urethra
Male reproductive
glands are the:
seminal vesicles (2)
Prostate (1)
bulbourethral glands (2)

6. Male Reproductive Anatomy
The scrotum is a supporting structure for the testes
It consists of a sac of loose skin and superficial fascia that hangs from the root of the penis
The location and contraction
of muscle fibers (dartos and
cremaster muscles) regulates
the testicular temp to that
required for sperm production
(2-3o below the core temp)

7. Male Reproductive Anatomy
The spermatic cord is a supportive structure that ascends “out of” the scrotum, and consists of:
The vas deferens
The testicular artery (of course this
is going into the scrotum)
Veins and lymphatics that
drain the testes and carry
testosterone to the body
Autonomic nerves

8. Male Reproductive Anatomy
The spermatic cord and ilioinguinal nerve pass through the inguinal canal, a passageway in the aponeuroses of the abdominal muscles (transversus abdominus, internal oblique, and external
oblique muscles)
In women, the round
ligament of the uterus and
the ilioinguinal nerve pass
through a very small
inguinal canal

9. Male Reproductive Anatomy
The tunica albuginea (collagen) forms septa that divide each testis into compartments
called lobules
Each lobule contains 1-3
seminiferous tubules
where sperm are
produced

10. Male Reproductive Physiology
Prenatal secretion of testosterone assists testicular descent and development of male external genital
Secretion of testosterone at puberty leads to development of male secondary sexual characteristics
stimulation of anabolism (musculoskeletal and protein growth)
hair growth patterns
lowering of the voice
development of libido (sexual drive)

11. Spermatogenesis
Spermatozoa are produced in the seminiferous tubules by sperm stem cells called spermatogonia
At the beginning of puberty, the
anterior pituitary increases secretion
of the gonadotrophs LH and FSH
Follicle-stimulating hormone
(FSH) stimulates Sertoli cells
and increases the rate of
spermatogenesis
FSH in males
In sexually-mature males, FSH acts on spermatogonia stimulating (with the aid of testosterone) the production of sperm.
LH in males
LH acts on the interstitial cells (also known as Leydig cells) of the testes stimulating them to synthesize and secrete the male sex hormone, testosterone. LH in males is also known as interstitial cell stimulating hormone (ICSH).

12. Spermatogenesis
LH stimulates Leydig cells, which are located between seminiferous tubules, to secrete the hormone testosterone (synthesized from cholesterol)
Once the degree of spermatogenesis (sperm formation) required for male reproductive functions
has been achieved,
Sertoli cells release
inhibin, a hormone
that inhibits FSH

13. Spermatogenesis
Spermatogonium to primary spermatocytes is mitosis. Meiosis takes a 2n primary spermatocyte to a 1n spermatid

14. Spermatozoa
Each day about 300 million sperm complete the process of spermatogenesis. A sperm contains several structures that are highly adapted for reaching and penetrating a secondary oocyte
The major parts of a sperm are the head and the tail
the nucleus contains 23 highly condensed chromosomes (half the normal number)
covering the anterior two-thirds of the nucleus is the acrosome

15. Spermatozoa
The acrosome is a cap-like vesicle filled with enzymes (hyaluronidase and proteases)
that help a sperm to penetrate
a secondary oocyte to bring about
fertilization
The middle piece contains many
mitochondria which provide
the energy (ATP) for locomotion

16. Spermatozoa Before ejaculation, sperm travel via the following route:
Seminiferous tubules
Rete testis (network)
Efferent ducts
Ductus epididymis
Vas (ductus)
deferens…