Histology of The Male Reproductive Tract
• Male reproductive system is made up of:
o Paired testes (lie in the scrotal sac)
o Paired ducts from the testes, accessory glands, and penis.
• Pathway of sperm:
o Seminiferous tubules ➔ straight tubules ➔ Rete testis ➔ efferent
ductules ➔ epididymis ➔ vas deferens ➔ ejaculatory duct ➔ urethra
➔ outside
Testis
Interstitial tissue
• The testis consists of seminefrous tubules which produce spermatozoa
• Each tubule loops around and releases spermatozoa at both ends
• Between tubules, there is a stroma (connective tissue) that contains:
o Blood vessels
o Lymphatics
o Interstitial / Leydig cells:
▪ Chief source of testosterone
▪ Can be seen as a single cell or in small clusters
▪ seen in close proximity to blood vessels / lymphatics
▪ Have an acidophilic cytoplasm, that is foamy due to the
presence of hormones (contain lipid droplets that hold the
steroid)
o Myoid / myoepithelial cells
▪ Contractile cells that help propel the spermatozoa
▪ Can be seen at the basement membrane
Seminiferous tubules
• Lined by COMPLEX (differentiated) STRATIFIED EPITHELIUM that consists
of two cells:
o Cells of the spermatogenic cell lineage (1 spermatogonia makes 64
spermatids/ spermatozoa):
1. Spermatogonia:
• Lie on the basement membrane
• Undergo mitosis
• Have three types (need to know that there is three types
but not necessarily differentiate between them):
o Type A (Dark) – reserve type
o Type A (Pale) – divide mitotically to form other
spermatogonia
o Type B – committed to become a spermatocyte
2. Primary spermatocytes
• Largest cells
• Are distinguishable a little bit above the basement
membrane
• Undergo the first meiotic division to form two
secondary spermatocytes
, • Very abundant as they are in prophase and that takes a
long time
3. Secondary spermatocyte
• Not really seen as they have a short life (around 8
hours)
• Undergo second meiotic division to become spermatids
4. Spermatids:
• Can be seen very close to the luminal surface
• Are small in size
• Undergo remodeling (spermiogenesis):
o Initially round cells (early spermatids)
o Become elongated (spermatozoa) through:
▪ Losing cytoplasm
▪ Condensation / elongation of nucleus
▪ Acquisition of acrosome
▪ Formation of flagella (crus missiles) that
are a marker of spermatozoa
o Serotoli / support cells:
▪ Columnar cells
▪ Give structural and metabolic support
▪ Do not undergo replication after puberty
▪ Transverse the entire interstitum – go from the basement
membrane to the lumen.
▪ Nuclei are large / euchromatic. Nucleoli can be seen.
▪ Nuclei are ovoid in shape, could be pyramidal, cell boundaries
not clearly seen.
▪ Secrete Androgen binding protein, inhibin (hormone)
▪ Form tight junctions through their lateral processes that makes
two functional compartments in the seminfirous tubules:
• Basal compartment: contain the spermatogonium
• Adluminal compartment: cells here are immune
protects and not accessible to antibodies (blood – testis
barrier). This means that the body does not recognize
the gametes as foreign and this does not create an
autoimmune response.
o All the daughter cells in the lineage remain cytoplasmically attached to
their parents until the spermatozoa are released.
,
• Male reproductive system is made up of:
o Paired testes (lie in the scrotal sac)
o Paired ducts from the testes, accessory glands, and penis.
• Pathway of sperm:
o Seminiferous tubules ➔ straight tubules ➔ Rete testis ➔ efferent
ductules ➔ epididymis ➔ vas deferens ➔ ejaculatory duct ➔ urethra
➔ outside
Testis
Interstitial tissue
• The testis consists of seminefrous tubules which produce spermatozoa
• Each tubule loops around and releases spermatozoa at both ends
• Between tubules, there is a stroma (connective tissue) that contains:
o Blood vessels
o Lymphatics
o Interstitial / Leydig cells:
▪ Chief source of testosterone
▪ Can be seen as a single cell or in small clusters
▪ seen in close proximity to blood vessels / lymphatics
▪ Have an acidophilic cytoplasm, that is foamy due to the
presence of hormones (contain lipid droplets that hold the
steroid)
o Myoid / myoepithelial cells
▪ Contractile cells that help propel the spermatozoa
▪ Can be seen at the basement membrane
Seminiferous tubules
• Lined by COMPLEX (differentiated) STRATIFIED EPITHELIUM that consists
of two cells:
o Cells of the spermatogenic cell lineage (1 spermatogonia makes 64
spermatids/ spermatozoa):
1. Spermatogonia:
• Lie on the basement membrane
• Undergo mitosis
• Have three types (need to know that there is three types
but not necessarily differentiate between them):
o Type A (Dark) – reserve type
o Type A (Pale) – divide mitotically to form other
spermatogonia
o Type B – committed to become a spermatocyte
2. Primary spermatocytes
• Largest cells
• Are distinguishable a little bit above the basement
membrane
• Undergo the first meiotic division to form two
secondary spermatocytes
, • Very abundant as they are in prophase and that takes a
long time
3. Secondary spermatocyte
• Not really seen as they have a short life (around 8
hours)
• Undergo second meiotic division to become spermatids
4. Spermatids:
• Can be seen very close to the luminal surface
• Are small in size
• Undergo remodeling (spermiogenesis):
o Initially round cells (early spermatids)
o Become elongated (spermatozoa) through:
▪ Losing cytoplasm
▪ Condensation / elongation of nucleus
▪ Acquisition of acrosome
▪ Formation of flagella (crus missiles) that
are a marker of spermatozoa
o Serotoli / support cells:
▪ Columnar cells
▪ Give structural and metabolic support
▪ Do not undergo replication after puberty
▪ Transverse the entire interstitum – go from the basement
membrane to the lumen.
▪ Nuclei are large / euchromatic. Nucleoli can be seen.
▪ Nuclei are ovoid in shape, could be pyramidal, cell boundaries
not clearly seen.
▪ Secrete Androgen binding protein, inhibin (hormone)
▪ Form tight junctions through their lateral processes that makes
two functional compartments in the seminfirous tubules:
• Basal compartment: contain the spermatogonium
• Adluminal compartment: cells here are immune
protects and not accessible to antibodies (blood – testis
barrier). This means that the body does not recognize
the gametes as foreign and this does not create an
autoimmune response.
o All the daughter cells in the lineage remain cytoplasmically attached to
their parents until the spermatozoa are released.
,
