Male Reproductive System

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Male Reproductive System
Qiu Shudong
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Introduction

• Testes
• Genital ducts
• Epididymis,
• Ductus deferens,
• Ejaculatory ducts
• Urethra
• Accessory glands
• Seminal vesicles,
• Prostate,
• Bulbourethral gland
• Penis

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• TESTES
• I. General Structure
• Tunica vaginalis
  (mesothelium)
• Testicular Tunica albuginea
• capsule mediastinum
  testis
• Tunica vasculosa (l.c.t
  Cap.)
• Septula testis
• Testicular Seminiferous tubule
• lobules Straight tubules,rete testis
  efferent ductules
• Interstitial tissue Leydig
  cell
• Function Produce sperm sexual hormone

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Testicular lobules
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II. Seminiferous Tubules

• D 150 - 250um, 30 - 70cm long,
• Spermatogenic Spermatogenic cells
• epithelium Sertoli cells
• Basement membrane
• 
  Collagenous fibers
• Limiting membrane
• Myoid
  cells

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Seminiferous Tubules
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(l) Spermatogenic cell Spermatogenesis

• At puberty / FSH stimulating
• Spermatogenic cells differentiate to spermatozoa
• Successive spermatogenic cells

• spermatogonia
• primary spermatocyte
• secondary spermatocyte
• spermatids
• spermatozoa.
• Spermatogenesis The process from spermatogonia
  to spermatozoa.
• Including 3 phases

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A. Spermatocytogenesis spermatogonia primary
spermatocytes by mitosis

• B. Meiosis Spermatocytes
• spermatids, through 2 succeesive
  meiosis w/ reduction by half number of
  chromosomes half amount of DNA per cell
• C. Spermiogenesis
• Spermatids spermatozoa
• by modifying structures
• shape (no division).

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Spermatogenesis Spermiogenisis
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• (2) Spermatogonia Spermatocytogenesis
• Spermatogonium
• The most immature spermatogenic cell, on B.M.
• Round small (12 um), a round nucleus w/ l-2
  nucleoli finely-granulated chromatin.
• Spermatocytogenesis
• At sexual maturity, a series of successive
  mitoses to form
• (l) spermatogonia A (stem cells)
• (2) spermatogonia B, (
  primary spermatocyte).

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46 chromasomes 2n DNA

• 46 chromasomes
• 2n DNA

46 chromasomes 4n DNA
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• (3) Primary 2nd spermatocyte meiosis
• Primary spermatocyte
• In middle zone of the epithelium. Easy to
  seen in section (the first meiosis need 22 days)
• The largest one (16-18um) , nucleus w/
  prominent chromosomes, 46 (44 XY) 4N DNA.
• Primary spermatocyte ??? Secondary
  spermatocyte(by 1st meiosis)
• Secondary spermatocyte
• Near lumen. Difficult to observe in section
  (the second meiosis quickly completed).
• Round (12 um) a pale-stained nucleus, 23
  ( 22X or 22y) 2N DNA.
• Secondary spermatocyte ??? spermatids(by
  2nd meiosis)

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• (4) Spermatid spermiogenesis
• Spermatid
• Close to lumen. spherical (6 um).
• 23 (22X or 22Y) 1N DNA (haploid)
• Spermiogenesis
• A complex process that a round spermatid
  transforms into a tadpole-like spermatozoon (no
  further division occurs) .
• Including

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• (5) Human Spermatozoon
• 60 um long, consist of a head a tail.
• Head pear-shaped flattened w/ a nuclear a
  acrosome (contains hydrolytic enzyme important
  for fertilization).
• Tail 55um in length w/ a microtubular axoneme in
  the core.
• Subdivided into 4 segments
• (a)The neck, containing a centriole
  (connect)
• (b)The middle segment (5-7um), containing a
• sheath of mitochondria (provide
  energy).
• (c)The principal segment (45um), containing
  a
• fibrous sheath (support the tail).
• (d)The end piece (5-7um), containing a
• microtubular axoneme.

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Mis. Egg , I miss you very much!

• Mr. sperm,

Mr. Sperm , I miss you very much too !
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The Passage of the Sperm

• Seminiferous tubules
• straight tubules
• rete testis
• efferent ductules
• genital ducts

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2. Sertoli cells Columnar cell rest on B.M.,
the free surface reaches to lumen. spermatogenic
cells locate b/w adjacent cells Features
function

• LM no clear outline, basally-located, ovoid
  nucleus w/ a distinct nucleolus.
• EM
• (l) abundant sER., Gl., Ly., Mf., Mt.
• (2) Tight junctions present b/w adjacent
  Sertoli cells (isolate spermatogonia from other
  spermatogenic cells).

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• C. Function
• (l) Support nourish spermatogenic cells
• (2) Secrete fluid to help the sperm moving
• (3) Phagocytize digest the residual bodies
• (4) Synthesize secrete ABP (androgen binding
  protein) which combines androgen in seminiferous
  tubule to stimulate spermatogenesis
• (5) Form the blood-testis barrier Tight junctlon
  constitute the main part (rest B.M. limiting
  membrane). Fnction separates germ cells from
  immune system prevents auto-immune reaction.
• (6) Prevent some physical chemical factors from
  damaging germ cells, e.g. radiation, body
  temperature, infection

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III. Interstitial tissue

• B/w seminifeious tubules
• L.c.t. w/ small b.v. l. v., nerves Leydig
  cells
• a. in groups near b.v.
• b. large, round or polygonal, acidophilic, round
  nucleus w/ prominent nucleolus.
• c. EM abundant sER, tubular cristae Mit., lipid
  droplets rod-shaped crystalloids.

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• Function
• secrete testosterone
• for proliferation differentiation of germ
  cells,
• for development of genital system,
• for maintenance of male secondary sex
  characteristics.

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• IV. Regulation of testicular function
• 1. Leydig cells are controlled by interstitial
  cell stimulating hormone (ICSH)
• 2. Follicle stimulating hormone (FSH) regulates
  the function of Sertoli cells
• 3. ICSH FSH are secreted by cells in glandular
  pituitary.

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Epididymis

• I. A head, a body a tail.
• II. Consist of a highly coiled ductus epididymis
• iii. The ductus is lined a pseudostratified
  columnar epithelium
• The principal cells have numerous stereocilia
• The base cells may be germinative

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• IV. Function
• Absorb most of the fluid that leaves the testis
• Secrete carnitine, glycerylphosphoryo-choline,
  sialic acid, etc.
• Spermatozoa become mature functionally, acquiring
  motility fertilizability when they slowly pass
  the ductus

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prostate

• Consist of compound glands around the urethra,
  c.t. and smooth muscles
• Glandular epithelium is columnar, cuboidal or
  pseudostratified.
• Prostatic concretions may be found in the alveoli
• Function
• The secretion containing acid phosphatase
  makes up the main part of seminal plasma
• Benign hypertrophy of prostate can lead to
• obstruction of the urethra.
• Prostate cancer developes in main glands

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