1. Chapter 19 Male Reproductive System
沈 阳 医 学 院
组织胚胎学教研室 丛敬

2. Ⅰ. General description
1. Consists of paired testes, genital ducts, accessory glands and penis.
2. Genital ducts
epididymis
ductus deferens
ejaculatory ducts
urethra.
3. Accessory glands
seminal vesicles
prostate
bulbourethral glands

3. Ⅱ. Testes 1. General structure Capsule -- 2 layers:
the visceral layer of tunica vaginalis
tunica albuginea
Mediastinum testis
Septum + testicular lobules
Interstitial tissue

4. C. Testicular lobules
--- highly coiled tubules contained in the lobules.
a. Composition:
Seminiferous tubules
Short straight tubules
Rete testis

5. Testis section

7. b. Seminiferous tubules
germinal epithelium:
- a specialized stratified epi
- consists of 2 types of cells:
spermatogenic cells (male reproductive cells)
Sertoli cells
Lamina propria:
basement membrane
collagen layer
myoid cells.

8. seminiferous tubules

9. Primary spermatocytes Secondary spermatocytes Spermatids Spermatozoa
2. Spermatogenic cells
--include 5 successive cells.
Spermatogonia
Primary spermatocytes
Secondary spermatocytes
Spermatids
Spermatozoa

10. A. Spermatogonia a. Adjacent to the BM, with round or ovoid nucleus.
b. Classified into type Ad, type Ap, and type B on the basis of nuclear staining.
type A--nucleolus in the periphera of nuclear,
Ad--nuclear dark ; Ap--nuclear pale
type B ---nucleolus in the center of nuclear c.
Type Ad (stem cells) →Type Ad → type Ad
type Ap → type B
Primary spermatocytes

11. spermatogenesis

12. B. Primary spermatocytes
--- (stop in the prophase of first meiosis for 22 days )
a.The largest cells with nuclei in various stages of meiosis, easily visible, nuclear as woolen ball
b. Contain diploid (2n)
chromosomes (44+XY)
and tetraploid (4n) DNA.
c. Undergo the first
meiosis (homologous
chromosomes separate)
producing the secondary
spermatocytes.

13. C. Secondary spermatocytes
a. Smaller cells near the lumen, with round nucleus, and few in number.
b. Contain haploid (1n) chromosomes (22+X or Y) and 2n DNA.
c. Quickly undergo the second
meiosis producing the spermatids.
※not easy to be seen for short-lived
and quickly divide into second
meiosis.

14. D. Spermatids and spermiogenesis
a. The smallest, round or ovoid cells close to the lumen.
b. Haploid cells (1n) in the
number of chromosomes and
in the amount of DNA.
c. Do not divide, and transform
from round cells into tadpole-
like spermatozoa by
spermiogenesis.
d. spermiogenesis:
spermatid spermatozoa

15. spermatozoon

16. d. Spermiogenesis includes following changes:
The nucleus becomes condensed and elongated.
Golgi apparatus transforms into vesicle and then acrosome.
Centrioles migrates to a position opposite acrosome and forms the flagellum (axoneme).
Mi move and aggregate around proximal part of the flagellum forming a sheath.
Much of cytoplasm is no longer required and cast off as residual bodies.

18. E. Spermatozoon
A mature spermatozoon has a head and a tail, about 60 m in length (head=5um,tail=55um)
tadpole in shape.

19. E. Spermatozoon
The head is pear-shaped, flattened and contains condensed nucleus (22+X or Y). The anterior 2/3 portion of the head is covered by the cap-like acrosome, which contains hydrolytic enzymes in it and is important for fertilization.

20. E. Spermatozoon
c. The tail is long and slender, containing a 9+2 microtubular axoneme (structure for motility) in its core. It is subdivided into 4 segments:
neck
middle
Principal
terminal piece

21. E. Spermatozoon ①The neck is very short and contains one centriole.
②The middle has a sheath of mitochondria which provides the energy for motility.

22. E. Spermatozoon
③The principal has a fibrous sheath providing support and protection.
④The terminal contains only the axoneme.

23. E. Spermatozoon
d. The spermatozoa in the testes appear morphologically mature but functionally immature, that is, they are non-motile and do not fertilize the ovum.

24. Spermatogenesis about 64 days from spermatogonium to spermatozoon
The spermatogenesis is the process by which spermatogonia divide and differentiate into spermatozoon
about 64 days from spermatogonium to spermatozoon
3 stages

25. Spermatogenesis

26. 3. Sertoli cell (supporting cell)
pyramidal in shape,
basal--close to the BM
apical--close to the lumen
lateral
--project to lateral processes
--tight junction

27. 3. Sertoli cell (supporting cell)
a. Irregular outline
b. Elongated triangular and pale-stained nucleus with a prominent nucleolus.
c. Abundant SER, as well as RER, Golgi apparatus, etc.
d. Tight junctions between adjacent cells near their bases, which lie in a basal compartment and adluminal compartment

28. e. function
support, protect, nourish, regulate and release germinal cell
secret androgen-binding protein (ABP); bind to androgen, maintain the level of androgen concentration of lumen. And inhibin suppresses FSH synthesis and release.

29. e. function
phagocytose degenerated cells and residual bodies from spermiogenesis.
constitute the blood-testis barrier
resistant to most factors: radiation,
high temperature, infection,
malnutrition, aging, etc.

30. blood-testis barrier constitute: endothelium and BM of capillary,
CT, and BM of seminiferous epithelium
tight junction between the Sertoli cells.

31. blood-testis barrier function:
--- provide micro-environment for spermatogenesis
--- avoid spermatozoon passing through the wall of
seminiferous tubule and from autoimmune reaction

32. 4. Leydig (interstitial) cells
Large, round or polygonal cells usually in groups, present in the interstitial tissue.
Nucleus is large, pale-stained with 1-2 nucleoli.
Cytoplasm is acidophilic and has abundant SER, lipid droplets, and Mi with tubular cristae.
Secrete testosterone under the control of LH.

35. Control factors during spermatgenesis
hypothalamus
hypophysis
testis
hormone
regulate
GnRH
FSH LH
Sertoli cell
interstitial cell (leydig)
ABP
Inhibin
androgen
spermatogenesis

36. 5. straight tubules ( tubulus rectus )
position: near the mediastinum testis
shape : straight and short canal
structure: simple cuboidal cells without seminiferous epithelium (thinner wall)

37. 6. rete testis position: within the mediastinum testis
shape: labyrinthine network (large and irregular lumen)
structure: as straight tubules

38. Ⅲ. Epididymis 1. Consist of : --head: the efferent ductules
(8-12 pieces).
--body and tail :
a highly coiled tube, ductus
epididymis (only 1 pieces).

39. 2. Ductus efferents
Ductus efferents have an epithelium composed of groups of nonciliated cuboidal cell alternating with ciliated cells.
The nonciliated cells absorb much of the fluid secreted by the seminiferous tubules. The cilia beat towards the epididymis and assist in the transportation of the spermatozoa.
The activity of ciliated cells and fluid absorption create a fluid flow that sweeps spermatozoa toward the epididymis.

40. 3. ductus epididymis
The ductus epididymis is lined with a pseudostratified columnar epithelium, containing 2 types of cells.
Tall principal cells form a smooth lumen surface andhave numerous stereocilia.
Short base cells may be germinative.

41. Ductus epididymis Ductus efferentes

42. epididymis duct
Efferent duct

43. 4. Has both absorptive and secretory functions
Absorbs most of the fluid that leaves the testis.
Secretes carnitine, glycerylphosphorylcholine,
sialic acid, etc.
Spermatozoa become mature functionally, acquiring motility and fertilizability when they
slowly pass the epididymis.

44. Ⅳ. Prostate
1. Compound glands around the urethra;

45. Ⅳ. Prostate covering: CT and SM parenchyma: 30-50 compound
tubuloaveolar gland.
-- mucosal gland in the innermost zone(within urethral mucosa)
-- submucosal gland in the middle zone (within submucosal layer)
-- main gland in the peripheral zone (other portions)

46. 2. simple epi ( cuboidal, columnar and pseudostratified )
3. within the cavity, there may be prostatic concretion,
HE: round or oval acidophilic bodies showing
concentric layers
※especially in older man.