Chapter 27
The Reproductive System
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27
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Basal compartment
Adluminal compartment
Spermatogenesis
Basal lamina
Spermatogonium
(stem cell)
Cytoplasm of adjacent
sustentocytes
Sustentocyte
cell nucleus
Tight junction between
sustentocytes
Spermatogonium
(stem cell)
Lumen of
seminiferous
tubule
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Meiosis (early spermatogenesis)
Spermiogenesis (late spermatogenesis)
Mitosis
Growth
Late spermatids
Early
spermatids
Secondary
spermatocytes
Cytoplasmic
bridge
Primary
spermatocyte
Spermatozoa
Type B daughter cell
Enters
meiosis I and
moves to
adluminal
compartment
Meiosis I
completed
Meiosis II
Type A daughter cell
remains at basal lamina
as a precursor cell
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(a) Scanning electron micrograph of a cross-
sectional view of a seminiferous tubule (165
m
)
(b)
Events of spermatogenesis, showing the relative
position of various spermatogenic cells
(c)
A portion of the seminiferous tublule wall, showing the
spermatogenic cells surrounded by sustentocytes (colored gold)
Figure 27.8
Spermatogenesis.
(Note: The process of
spermatogenesis encompasses the phases through the production
of sperm. Conversion of the haploid spermatids to sperm cells is
speci´Čücally called spermiogenesis.)
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