The testis and duct system consists of highly coiled seminiferous tubules in the testis that produce sperm through spermatogenesis. A system of ducts made up of the rete testis, epididymis, vas deferens, and ejaculatory duct collects and transports sperm. The seminal vesicles and prostate gland secrete fluids that nourish and transport sperm via the penis during ejaculation. Within the seminiferous tubules, Sertoli cells nurture germ cells and Leydig cells produce testosterone.

1. TESTIS AND DUCT
SYSTEM
Presenter Name: Dr. Kashif Hussain Alvi Awan

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• A System of Ducts consisting of ductuli efferentes, epididymis,
ductus (vas) deferens and ejaculatory duct collects,
stores and carries spermatozoa from each testis.
• Two Exocrine Glands, the paired seminal vesicles and the
single prostate gland, secrete a nutritive and lubricating
fluid medium called seminal fluid in which spermatozoa
are conveyed to the female reproductive tract.
• The Penis is the organ of copulation

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5. SEMINIFEROUS TUBULES
Each Seminiferous tubules is intricately coiled and average about 0.2 mm
in diameter and 50 cm in length usually commence as free blind ends but
neighbouring tubules may form anastomosing loops.
At the apex of the testicular lobules, seminiferous tubules lose their
convolution and becomes straight. These straight segments is known as
Tubuli recti.
The Tubuli recti passes into the mediastinum testis and join a network of
anastomosing channels called Rete testis.
From the Rete testis arises 10 to 20 spirally structure ‘efferent ducutles’
which leaves the testis and open into the duct of the epididymis. The
seminiferous tubules is lined by a complex seminiferous epithelium, a
modified stratified cuboidal epithelium.

6. The Seminiferous tubules are highly convoluted and are lined by:
 • Germ cells in various stages of spermatogenesis which are
collectively referred to as the spermatogenic series.
 • Non–germ cells, called Sertoli cells, which support and
nourish the developing spermatozoa are also found within the
Seminiferous tubules.
 • In the interstitial spaces between the tubules, endocrine cells
called Leydig cell are found either singly or in groups in the
supporting tissue.

8. SPERMATOGENIC CELLS
These cells lie between the Sertoli cells and forms a Stratified epithelium
consisting of several layers of cell which occupy the space between the
lamina and lumen of the seminiferous tubules. In the testis of a child, only
the primitive germ cells called spermatogonia are present.
However, with the onset of sexual maturity the process of
spermatogenesis starts and the spermatogenic cells are seen in various
stages of differentiation, arrange in an orderly manner. Usually 4 to 5
concentric layers of morphologically distinct spermatogenic cells
representing generations of cell at various stages of development can be
identified in the adult seminiferous epithelium.

9. The process of Spermatogenesis consist of:
• Spermatogonium
• Primary spermatocyte
• Secondary spermatocyte
• Spermatids
The spermatogonia are located directly inside the basal lamina of the
seminiferous epithelium. Depending on the nuclear structure, the spermatogonia
can be classified into three types in an adult person. These three types are:
1) The type A Dark spermatogonia
2) The type A Pale spermatogonia
3) The type B Spermatogonia

10. The type A Dark spermatogonia contains an oval , darkly staining nucleus. The are the
reserve cells and divide occasionally to maintain their own number and to give rise to type A
pale spermatogonia.
The type A Pale spermatogonia contain a lightly staining nucleus. These cells divide
mitotically to give rise to other type A pale spermatogonia as well as type B spermatogonia.
The type B Spermatogonia have a spherical nucleus . Mitotic division of the type B
spermatogonia produce daughter cell, all of which differentiate into Primary spermatocytes.
The Primary spermatocytes lie next to the spermatogonia. They are large cells having
vesicular nuclei.
The secondary spermatocytes are smaller cells that arise from a primary spermatocytes as a
result of the first meiotic division.
The Spermatids are produced from the secondary spermatocytes by the second meiotic
division. Spermatids does not divide further but is transformed into a spermatozoon by a
series of morphological changes which are collectively known as Spermatogenesis.

12. SERTOLI CELLS
The Sertoli cells are tall, columnar cells that extends from the basal lamina
to the lumen of the seminiferous tubules.
Each Sertoli cells is 70 to 90 um and nearly 30um wide. Due to their close
association with the spermatogenic cells, the lateral margins of the Sertoli
cells are irregular and cannot easily be distinguished under LM. Each Sertoli
cells has a large, pale staining nucleus which is located in then bas al
portion of the cells. The nucleus exhibits two distinctive features:
• The Nuclear envelop shows many folding
• The Nucleus is very prominent.
Luminal surface of the Sertoli cell shows many grooves in which head of
the mature in spermatozoa are embedded.

13. FUNCTION OF SERTOLI CELLS
• The Sertoli cell provide physical and nutritional support to the germ
cells.
• They established the important blood testis barrier, which prevents a
immune response against the developing germ cells.
• They carry out phagocytosis of then excess cytoplasm that is shed by
the spermatids during the process of spermatogenesis. The Sertoli
cells secretes AMH which promotes regression of the
paramesonephric ducts.
• It secretes a hormone called Inhibin that inhibits the production of
FSH by the anterior pituitary.
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15. LEYDIG CELLS
The Leydig cells are large ovoid cells that are arranged as group in close
association to blood capillaries.
Leydig cells are found in the interstitial supporting tissue between the
seminiferous tubules, synthesise and secrete the male sex hormones and
other non-steroid substances. The Leydig cell secretes the Male sex
Hormone Testosterone. This Hormone is released into the blood
capillaries as it is synthesized and therefore they do not exhibit any
secretory vesicles. Testosterone is not only responsible for the
development of male secondary sexual characteristics at puberty but is
also essential for the continued function of the seminiferous Epithelium.

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18. • Tubuli recti The seminiferous tubules at the apex of the testicular lobule joins
to form straight tubules called Tubuli recti. The proximal part of the straight
tubules is lined by Sertoli cells while the distal part is lined by simple cuboidal
epithelium.
• Rete testis A highly anastomotic network of channel lying in the dense
connective tissue of the mediastinum testis. The rete testis is lined by simple
cuboidal epithelium.
• Ductuli efferentes from each testis arise 12 or more ductuli efferentes . These
efferentes ductules emerge from the superior part of the posterior border of
testis. The ductuli efferentes are lined by simple columnar epithelium. The lining
epithelium consists of group of tall columnar ciliated cells alternating with groups
of tall columnar ciliated cells alternating with groups of non ciliated, low
columnar cells called Principal Cell.
• The principal cells are absorptive in function. They absorb most of the fluid
secreted in the seminiferous tubules.

19. EPIDIDYMIS
Epididymis is a comma shaped body that overlies the
posterior surface of the testis.
Epididymis is divided into 3 part:
• Head
• body and
• Tail
The Epididymis consist almost entirely of a single, complex convoluted duct called Ductus Epididymis. This
duct is 6 to 7 metres long and begins in the head of the epididymis. Cross section examination reveals that
the duct duct of epididymis is lined by a Pseudostratified columnar epithelium, composed of tall columnar
cells and basal cells.

20. FUNCTION OF EPIDIDYMIS
• Storage of spermatozoa
• Transportation of spermatozoa
• Reabsorption of most of the fluid the leave the testis
• Spermatozoa develops the motility, ability and maturity
to fertilize the ova.

21. DUCTUS DEFERENS
It is a narrow luminal structure and a thick muscular wall structure which consist of
the following 3 coats:
1. Mucosa
2. Muscularis
3. Adventitia
• The Mucosa is thrown into longitudinal folds due to which the lumen appears
star shaped in a cross section. The lining epithelium of the ductus deferens
closely resembles to that of the epididymis. It is a pseudostratified columnar
epithelium in which the tall columnar cells bears the stereocilia on their free
luminal surfaces.
• The Muscularis is very thick. It is composed of 3 layers of smooth muscles.
• The Adventitia surrounds the muscularis and consists of a thin layer of
connective tissue containing blood vessels and nerves.

22. The distal end of the ductus deferens is dilated to form the ampulla. It is
characterized by the presence of tall, highly branched mucosal folds with
glandular diverticula. The mucosa of the ampulla is lined by simple
columnar epithelium which is secretory in nature.

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24. SEMINAL VESICLES
Each seminal vesicles is a highly tortuous tube
which is about 15 cm long.
It consists of 3 coats:
• Mucosa
• Muscularis
• Adventitia
It is lined by Pseudostratified columnar epithelium that contains two types of
cells i.e. Principal Cells and Basal Cells. The seminal vesicles secretes 70%
of the volume of the semen. The secretory products of the seminal vesicles is
rich in fructose that serves as a nutritive material for the spermatozoa.

25. PROSTATE GLANDS
The prostate surrounds the initial part of the male urethra and is the largest accessory
sex gland of the male reproductive system. It is covered by a thin capsule of richly
vascularized, dense irregular connective tissue interspersed with smooth muscle cells.
The secretion of then prostate gland are discharged into the urethra by contraction of
the muscular stroma at the time of ejaculation. The prostate gland secretes PSA.
Depending upon the incident of disease in different part of the prostate, it is divided into
three zones:
• The peripheral zone constitute 70% of the glandular mass. It is most susceptible to
prostatic cancer.
• The transitional zone is the common site for BPH which occurs in the middle age.
• The central zone is resistant to hyperplasia as well as malignancy.

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28. SEMEN
The Semen consist of seminal plasma and spermatozoa. The
seminal plasma constitute about 95% of the volume. It serves as
an energy source and vehicle for the spermatozoa.
The Density of the Spermatozoa is highly variable i.e.,100
Million/ml. The normal volume of semen from a single ejaculation
varies from 2 to 6 ml.

29. PENIS
The penis consist of 3 cylindrical masses of erectile tissue. The paired Corpora
cavernosa lies dorsally while the single Corpus spongium lies ventrally.
The paired Corpora cavernosa are fused together in the body of penis but
diverge in the perineum to form crura of the penis. The Corpus spongiosum
enlarges proximally to form the bulb of the penis. Distally, it expands to form a
cup shaped enlargement, the glans penis which forms conical cap over the
conical ends of the corpora cavernosa.
In the Un-circumcised males, the glans penis is covered by a fold of skin called
Prepuce. The outer surface of the prepuce is covered by the ordinary
epidermis consisting of stratified squamous keratinized epithelium. However, its
inner surface is lined by stratified squamous non-keratinized epithelium. The
skin of the inner surface of the also contains a large number of sebaceous
glands secretion of which keeps the surface moist.

31. THANK YOU