Male Reproductive System
Reproductive Organs
- Major function is to produce and
deliver sperm to female
- Temperature control is key
- Testes need to be 4-6C
below core temp for
spermatogenesis
- Later in life: controlled by
the veins of the
pampliform plexus
forming a countercurrent
heat exchanger (decrease
temp of arterial blood
entering the testes)
- Testes located in scrotum (skin sac
with layers of smooth muscle)
- Inside scrotum has layers of connective tissue
- Covering the testes is a layer of
vascularized connective tissue that
projects septa in the testes
- Tunica albuginea where BV enter to
feed testes
- Within testes called mediastinum
- Inside Testes
- Seminiferous tubules: site of sperm
production, ducts collect sperm to rete
testis in the center = tubes that bring the
sperm to epididymis
- Contain sertoli cells manage
sperm transport
- Sealed by basal lamina and
tight junctions
- Interstitium: between ST, composed of connective tissue, BV, and leydig cells which
produce testosterone
Spermatogenesis
- Progenitor cells: spermatogonium
- Mitotic division
- When they divide, moves from basal lamina to the lumen of the ST
- Happens bw 2 sertoli cells (control differentiation process)
- Meiosis
, - Interphase: replication of DNA
- Prophase I: critical to make unique sperm, increase genetic diversity, primary
spermatocyte
- Leptotene: condensation of chromatin
- Zygotene: pairing of homologues
- Pachytene: crossing over and recomb
- Diplotene: synaptonemal complex disappearing, chiasma visible
- Diakinesis: nuclear envelope fragmenting, bivalent ready for metaphase
- Metaphase I: centromere binds to spindle fiber
- Anaphase I: homologous pairs separate and begin to move
- Telophase I: chromosomes migrate to each pole, cell division
- Prophase II: spindle fibers rearrange and chromosomes recondense, secondary
spermatocyte
- Metaphase II: chromosomes align along spindle equator
- Anaphase II: sister chromatids separate and move to opposite poles
- Telophase II: daughter cell nucleus has one set of chromosomes, spermatids
- Sertoli Cells
- Blood testis barrier
- Basal/luminal and adluminal compartments
- Provide nutrients and several factors to control spermatogenesis
- Fluid pumping during final maturation of sperm, get rid of excess cytoplasm
- Produce androgen binding protein and inhibin - ABP as a carrier for testosterone, and
inhibin for regulation of testis function
- Express FSH receptors
Spermiogenesis
Reproductive Organs
- Major function is to produce and
deliver sperm to female
- Temperature control is key
- Testes need to be 4-6C
below core temp for
spermatogenesis
- Later in life: controlled by
the veins of the
pampliform plexus
forming a countercurrent
heat exchanger (decrease
temp of arterial blood
entering the testes)
- Testes located in scrotum (skin sac
with layers of smooth muscle)
- Inside scrotum has layers of connective tissue
- Covering the testes is a layer of
vascularized connective tissue that
projects septa in the testes
- Tunica albuginea where BV enter to
feed testes
- Within testes called mediastinum
- Inside Testes
- Seminiferous tubules: site of sperm
production, ducts collect sperm to rete
testis in the center = tubes that bring the
sperm to epididymis
- Contain sertoli cells manage
sperm transport
- Sealed by basal lamina and
tight junctions
- Interstitium: between ST, composed of connective tissue, BV, and leydig cells which
produce testosterone
Spermatogenesis
- Progenitor cells: spermatogonium
- Mitotic division
- When they divide, moves from basal lamina to the lumen of the ST
- Happens bw 2 sertoli cells (control differentiation process)
- Meiosis
, - Interphase: replication of DNA
- Prophase I: critical to make unique sperm, increase genetic diversity, primary
spermatocyte
- Leptotene: condensation of chromatin
- Zygotene: pairing of homologues
- Pachytene: crossing over and recomb
- Diplotene: synaptonemal complex disappearing, chiasma visible
- Diakinesis: nuclear envelope fragmenting, bivalent ready for metaphase
- Metaphase I: centromere binds to spindle fiber
- Anaphase I: homologous pairs separate and begin to move
- Telophase I: chromosomes migrate to each pole, cell division
- Prophase II: spindle fibers rearrange and chromosomes recondense, secondary
spermatocyte
- Metaphase II: chromosomes align along spindle equator
- Anaphase II: sister chromatids separate and move to opposite poles
- Telophase II: daughter cell nucleus has one set of chromosomes, spermatids
- Sertoli Cells
- Blood testis barrier
- Basal/luminal and adluminal compartments
- Provide nutrients and several factors to control spermatogenesis
- Fluid pumping during final maturation of sperm, get rid of excess cytoplasm
- Produce androgen binding protein and inhibin - ABP as a carrier for testosterone, and
inhibin for regulation of testis function
- Express FSH receptors
Spermiogenesis
