The Human Reproductive system

THE HUMAN REPRODUCTIVE SYSTEM
• Human produce offspring by a process called sexual reproduction in which haploid
sperm cells produced by the testes of male fertilize the haploid secondary oocytes
produced by the ovaries of females.
• As a result of fertilization, the resulting diploid cell is called a zygote.
• It contains one set of chromosomes from each parent.

Male Reproductive System
• The organs of the male reproductive system include
1. the testes,
2. a system of ducts (epididymis, ductus deferens, ejaculatory
ducts and urethra),
3. accessory sex glands (seminal vesicles, prostate and
bulbourethral glands)
4. and several supporting structures like the scrotum and penis.

• Semen, a bodily fluid, contains sperm plus the secretions
provided by the accessory glands.
Functions of the Male Reproductive System are as follows:
• The testes produce sperm and the male sex hormone
testosterone.
• The ducts transport, store and assist in maturation of sperm. Fig 1: Male Reproductive system
• The accessory sex glands secrete most of the liquid portion
of semen.
• The penis contains the urethra, a passageway for ejaculation of semen and excretion
of urine.
• The branch of medicine that deals with male disorders, especially infertility and
dysfunction is called andrology.
Parts of the Male Reproductive system
1. Scrotum
• The scrotum is the supporting structure for the testes
consisting of loose skin and underlying subcutaneous
layer that hangs from the root of the penis.
• Externally, the scrotum looks like a single pouch of
skin separated into lateral portions by a median ridge
called the raphe.
• Internally, the scrotal septum divides the scrotum into
two compartments, each containing a single testis.
• The septum is made up of a subcutaneous layer and
muscle tissue called the dartos muscle, which is Fig 2: Scrotum
composed of bundle of smooth muscle fibers.




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, • Associated with each testis in the scrotum is the cremaster muscle, a series of small
bands of skeletal muscle that descend as an extension of the internal oblique muscle
through the spermatic cord to surround the testes.
• Fascia is a sheet of connective tissue that surrounds, supports and separates muscles,
organs and other structures.
• The spermatic Cord Fascia is of three layers of fascia:
a. External Spermatic Fascia
b. Cremasteric Fascia
c. Internal Spermatic Fascia


2. Testes
• The testes or testicles are paired oval glands in the scrotum measuring about 5 cm
long and 2.5 cm in diameter and has a mass of 10-15 g each.
• They develop near the kidneys and they usually begin their descent into the scrotum
through the inguinal canals.
• A serous membrane called the tunica vaginalis
partially covers the testes.
• A collection of serous fluid in the tunica vaginalis
is called hydrocele.
• Internal to the tunica vaginalis the testis is
surrounded by a white fibrous capsule composed
of dense irregular connective tissue, the tunica
albuginea.
• This extends inward forming septa that divide the
testis into lobules.
• Each of the 200-300 lobules contains one to three
tightly coiled tubules, the seminiferous tubules Fig 3: Testes
where sperm are produced.
• Embedded among the spermatogenic cells in the seminiferous tubules are large
sustentacular cells which extend from the basement membrane to the lumen of the
tubule.
• Functions of sustentacular cells are as follows:
a. Support and protect developing spermatogenic cells.
b. Nourish spermatocytes, spermatids and sperms.
c. Controls movements of spermatogenic cells and the release of sperm into the lumen
of seminiferous tubule.
d. Produce fluid for sperm transport, secrete the hormone inhibin and regulate the
effects of testosterone and follicle stimulating hormone.




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