Male reproductive system
LECTURE FOR MEDICAL STUDENTS
DEPARTMENT OF HISTOLOGY,
CYTOLOGY AND EMBRYOLOGY KhNMU
2012
The internal male genitalia:
•
•
•
•
the testes
the epididymis,
the vas deferens
the accessory sex
glands - the seminal
vesicles,
the prostrate and
the bulbourethral glands
Functions:
• Reproductive --- produce the male
•
gametes or spermatozoa, and
Endocrine --- produce male sexual
hormone (testosterone)
Testes
The structure of Testes
Connective tissue
• a thick capsule - the
tunica albuginea
• the mediastinum testis,
•
projects into the testis
and give septae
Septae – divide testes on
200-250 lobules
Each Lobule consist of:
• Connective
•
tissue -Interstitium -with Leidig
cell
Seminiferous
tubules (1-4
per lobule)
Leydig cells (15-20 µm)
• synthesise and
secrete
testosterone.
The Convoluted Seminiferous
Tubules
Consists of two
types of cells:
• spermatogenic
cells
• Sertoli cells.
Spermatogenic cells
• Spermatogonia - Type A spermatogonia
- Type B spermatogonia
• Primary spermatocytes
• Secondary spermatocytes
• Spermatids
• Spermatozoa
Spermatogenesis
• Type A
•
spermatogonia are
stem cells
which divide to form
new generations of
spermatogonia.
Spermatogenesis
• Type B
spermatogonia ---
their final mitosis always
results in the
formation of Primary
spermatocytes
• Primary
•
spermatocytes appear
larger than
spermatogonia.
They immediately
enter the prophase of
the first meiotic
division, which is
extremely prolonged
(about 22 days!).
• The completion of the
first meiotic division
results in the
formation of
Secondary
spermatocytes
• Secondary
•
spermatocytes, are
smaller than primary
spermatocytes.
They rapidly enter
and complete the
second meiotic
division.
• Their division results
in the formation of
Spermatids, which
lie in the luminal part
of the seminiferous
epithelium.
• The terminal phase of
spermatogenesis is
called spermiogenesis
• and consists of the
differentiation of the
newly formed
spermatids into
Spermatozoa
Spermatogenesis
• Cell divisions are
incomplete. The cells
remain connected by
bridges of cytoplasm.
Structure of spermatozoa
Sertoli cells
• - provide mechanical
support
for
the
spermatogenic cells.
• -- provide bloodtestis barrier.
• --- have a nutritive
function.
Eccurrent ducts
• MRS consists of
DUCTS
epididymis - anatomy
• The head of the epididymis receives the
efferent ductules.
• The tail of the epididymis leads into the
vas deferens.
efferent ductules
Epididymis
ductus epididymidis
It is lined by a very tall
pseudostratified
columnar epithelium:
• principal cells, (have
long stereocilia)
• basal cells
ductus epididymis
• The epididymal
•
duct is extremely
long (4 to 5 meters)
but is highly
convoluted
It is surrounded by
smooth muscle and
embedded within a
loose, vascular
stroma.
Male Accessory Reproductive
Glands
Seminal Vesicles
Seminal Vesicles
functions:
• the formation of the
•
sperm coagulum,
the regulation of
sperm motility and
Male Accessory Reproductive
Glands
Prostate
• is the largest accessory
•
sex gland in men (about
2 x 3 x 4 cm).
The secretion contains
citric acid, the enzyme
fibrinolysin , acid
phosphatase, a number
of other enzymes and
lipids.
Male Accessory Reproductive
Glands
• It contains 30 - 50
tubuloalveolar glands,
which empty into 15 25 independent
excretory ducts.
These ducts open into
the urethra.
• the peripheral zone
•
•
contains large, socalled main glands,
whose ducts run
posteriorly to open
into the urethra.
the internal zone
consists of the socalled submucosal
glands, whereas
the innermost zone
contains mucosal
glands.
Male Accessory Reproductive
Glands
• The glands are
embedded into a
fibromuscular stroma,
which consists of
smooth muscle and
connective tissue rich
in collagenous and
elastic fibres.
Male Accessory Reproductive
Glands
Prostate
• The epithelium is
cuboidal or columnar.