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Anhui Medical University
Anhui Medical University
Male Reproductive System
Li Hong E-mail: [email protected] of Histology and Embryology
Anhui Medical University
Anhui Medical University
Anhui Medical University
contentsGeneral description
Testis
Epididymis
Prostate
Anhui Medical University
Anhui Medical University
1. Consist of spermatogenic epithelium
2. The structure and functions of supporting cell
3. The structure and functions of Leydig cell
4. The structure of blood-testis barrier
Key points
Anhui Medical University
Anhui Medical UniversityGeneral Description
TestesExcretory genital ducts:
epididymisductus deferensejaculatory ductsurethra
Accessory glands:prostateseminal vesiclesbulbourethral glands
Peniscolpulative organ
Anhui Medical University
Anhui Medical UniversityTestisLocated in the scrotum
Ovoid or flattened
Being covered by testicular capsule:
tunica vaginalis and tunica albuginea
Anhui Medical University
Anhui Medical University
General structure
一 Testis
CapsuleTunica vaginalis:serosa
Tunica albuginea:thick, DCT• mediastinum testis: albuginea became thicker
at posterior portion• septum: thin septa extend radiately from
mediastinum testis to divided the parenchymainto lobule
LobuleTesticular interstitial tissue:LCT
between seminiferous tubule
Seminiferous tubule: highly coiled;30-70 cm long;150-250 mm in D
Anhui Medical University
Anhui Medical University
Tubuli recti
Anhui Medical University
Anhui Medical University
Each testis is composed of about 250pyramidal compartments called the testiculerLobules. Each lobule is occupied by 1-4seminiferous tubules enmeshed in a web ofLCT that is rich in blood and lymphaticVessels ,nerves and interstitial (Leydig) cell.
Anhui Medical University
Anhui Medical University
Testis
Anhui Medical University
Anhui Medical University(一)Seminiferous Tubule
Spermatogenic epithelium
Spermato-
genic cell
Spermatogonium Primary spermatocytesSecondary spermatocyteSpermatidSperm
Supporting cell
Basement membrane
Tunica propria(myoid cell)
Anhui Medical University
Anhui Medical UniversitySeminiferous tubules
Supporting or Sertoli cells
Spermatogenic cells
Basement membrane
Tunica propria and myoid cell (3-5 layers )
Germinal or seminiferous epithelium
Anhui Medical University
Anhui Medical University
1、spermatogenic cell
They are arranged in 4-8 layers since puberty. The cells replicate and migrate from the basal region of the seminiferous tubule to lumen as they mature.
1)Spermatogonium
(a primitive germ cell)
2)Primary spermatocyte
3)Secondary spermatocyte
4)Spermatid
5)Sperm (spermatozoa)
Anhui Medical University
Anhui Medical University
Adjacent to the basal membrane
Round or ellipsoid, small (10-12 µm)
1)Spermatogonium
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Anhui Medical University
1)SpermatogoniumStructure:Is a relatively small cell, about 12micrometer in diameter; round nucleus, deepstained by HE staining; situated next to thebasement membrane
Anhui Medical University
Anhui Medical UniversityClassification :
type A:dark typeA(Ad):ovoid,deep-stained,nucleus,stem cellPale type A(Ap):ovoid, pale-stained,nucleus, differentiate into type B.
type B:round Nucleus, chromatin granules are distributedunder nucleus membrane, division and differentiate into primaryspermatocyte A
p B
Ad
Anhui Medical University
Anhui Medical University
Proliferation and differentiation of
Spermatogonium
Seminiferous tubules
(stem cell)
Anhui Medical University
Anhui Medical University2) Primary spermatocyteThe primary spermatocyte has 46 (44+XY) chromosomes
and 4n amount of DNA soon after their formation, thesecells enter the prophase of the first meiotic divition. Since theprophase of this division takes about 22 days, the majority ofspermatocytes seen in sections will be in this phase. Fromthis first meiotic divisionarise smaller cells calledsecondary spermatocytes.
Structure : roundcell, become largest, 18micrometer. large andround nucleus.
Anhui Medical University
Anhui Medical University
Primary spermatocyte
Anhui Medical University
Anhui Medical University
46 chromosomes (44+XX or XY) and 4n DNA (tetraploid)First meiosisLong prophase (up to 22 days)Frequently visible
Primary spermatocyte
Anhui Medical University
Anhui Medical University
3)Secondary spermatocyte
Nearer the lumen. The secondary spermatocyte has 23 Xor 23 y chromosomes and 2n amount of DNA.
Through secondary meiosis, a cell divides into twospermatids.
The secondary spermatocytes are difficult to observe insections because they are short-lived cells that remain ininterphase very brieflyand quickly enter intothe second meioticdivision.
Structure: Round cell, 12 micrometer in diameter. Round and deeper stained nucleus,
Anhui Medical University
Anhui Medical University
Secondary spermatocyte
By second meiotic division without prior duplication
of DNA, resulting in haploid spermatids
Anhui Medical University
Anhui Medical University4) Spermatid
Structure:smallest cell, 8 micrometer
located at innerest layerThe spermatid has 23 X or 23
y chromosomes and 1n amount of DNA.
Through spermiogenesis: spermatid transform into sperm
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Anhui Medical University
Spermatid
Anhui Medical University
Anhui Medical University5)SpermStructure : Head:pear-shaped, flattened,
nucleus and acrosome Tail:flagellum
The axial core of whole tail iscalled axoneme which is consists of9+2 microtubules and surroundedby the outer dense fibers arrangedin longitudinal.Tail compose of 4 parts:
1) neck: a pair centriole2) middle segment:mitochondria sheath3) principal segment:fiber sheath4) end segment:only axoneme
Anhui Medical University
Anhui Medical University
Testis HE ×100
Testis HE ×400
Anhui Medical University
Anhui Medical University
It is characterised by the following events:
(1) condensation and elongation of Nucleus
(2) formation of the acrosome
-cover the anterior and lateral portion of N
-contain hydrolytic enzymes for fertilization
(3) formation of flagellum: for motility
(4) formation of mitochondria sheath
(5) discharge of useless organelle and cytoplasm
Spermiogenesisspermatid become into sperm
Anhui Medical University
Anhui Medical University
Spermiogenesis
Anhui Medical University
Anhui Medical UniversitySpermatogenesis
Spermatogonium become into sperm
Sperm
Spermatogonium
Spermatid
Secondary spermatocyte
Primary spermatocyte
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Anhui Medical University
Proliferation and differentiation of
Spermatogonium
Seminiferous tubules
(stem cell)
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Anhui Medical University
Light Microscope : sperm
Anhui Medical University
Anhui Medical UniversityScanning Electron Microscope : sperm
Anhui Medical University
Anhui Medical University2 Supporting cell
Structure:
1)LM:-columnar or pyramidal cell-rest on basal lamina-extending into lumen-no clear boundary-elongated nucleus: triangular, ovoid, paler-
stained, with prominent nucleolus
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Anhui Medical University
Anhui Medical University
Anhui Medical University
2)EM
-rich SER, some RER,Golgi complex
-mitochondria , lysosome
-glycogen, lipid droplet
-tight junction
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Anhui Medical University
3)Functions
① . support, protect and nutrition,
②. secrete androgen-binding protein (ABP)
Function of ABP: bind to androgen, maintain the level of androgen concentration of lumen
③. phagocytose spermiogenic residual bodies
④. constitute the main parts of blood-testis barrier
Anhui Medical University
Anhui Medical University
Components:
Endothelium
Basal lamina of endotheliumConnective tissueBasal lamina of seminiferous tubuleTight junction of supporting cell
Functions:Protect the seminiferous cells from auto-immune
reaction, resistant to most harmful factors.
3 blood-testis barrier
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Anhui Medical University
(二) Interstitial tissue of testisLoose Connective Tissue Interstitial Cells (Leydig cell)
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Anhui Medical University
LM EM
Distribution of leydig cell: in groups
Structure:LM: -large, polygonal-shaped cell, with round nucleus
-acidophilic cytoplasmEM: they have the features of steroid-secreting cell
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Anhui Medical University
Secreting androgen which is essential for
Proliferation and differentiation of germ celll
The proper maintenance of the genital ducts and accessory glands
Development and maintenance of male second sex characteristics
Function of leydig Cells:
Anhui Medical University
Anhui Medical University二 Epididymidis
→Epididymal duct.
1 Structure
Head→Efferent duct
Body
Tail
Anhui Medical University
Anhui Medical University1)Efferent duct:
Scallop-like
Extending from the rete testis, forming the head of the epididymis
Tall columnar cells, ciliated: Secrete some fluid
Short columnar cells, nonciliated, numerous microvilli: Absorption of fluid and granulated matter
Anhui Medical University
Anhui Medical University2)Epididymal duct:
4-6 m in length, 0.4 mm in diameter Pseudostratified columnar epithelium
Pricipal cell: Tall in the head, low columnar in the tail, with long microvilli
Basal cell: Small, round and pale-staining, located in the base of the epithelium
Basal cell
Pricipal cell
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Anhui Medical University
Absorption of fluid that leaves the testis
Secretion of glycerylphosphorycholine, sialic acid, glycoproteins, steroids
Promoting functional maturation of the sperm
Storing mature sperm, in the tail
Forcing the sperm into the ductus deferens by the contraction of smooth muscle
Function of Epididymal duct
Anhui Medical University
Anhui Medical University三、Ductus deferensStructure:
Thick wall, narrow lumenmucosa, muscularis and adventitia
1) Mucosa: similar epithelium to that of the epididymal ductwith long microvilli in the tall columnar cell.
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Anhui Medical University
2) Muscularis: three layers Inner: longitudinalmiddle: circular outer: longitudinal
The powerful contraction rapidlytransports the sperm through the ductus deferens during ejaculation
3) Adventitia
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Anhui Medical University
Structure
四 Prostate
Function: secrete prostatic fluidThe semen is composed of sperm, secretory fluid of genital
ducts and accessory glands
The prostate is the largest accessory sex gland, with a weight of approximately 20 gram. Consisting of 30-50 compound tubuloalveolar glands.
Secretory portion:1)prostatic epithelium2)prostatic concretions are
observed in the lumen
Interstitial tissue :elastic fiber and smooth muscle in rich
Anhui Medical University
Anhui Medical UniversityProstate
Prostatic concretion
(eosinophilic body)
Smooth muscle
Prostatic epithelium
Anhui Medical University
Anhui Medical University
1. What is spermatogenic epithelium consist of ?
2. What are the main functions of supporting cell ?
3. Describe the structure and functions of Leydig cell.
4. Describe the structure and functions of blood-testis barrier.
Questions
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