Fundamentals of Anatomy and Physiology

Cellular Metabolism and Reproduction: Mitosis and Meiosis 81

Spermatogonium

Chromosomes shorten and

thicken. Each pair consists

of four chromatids (tetrad).

Chromosomes join

in homologous pairs.

Prophase 1

Chromatid components (^)
A random assortment of continue to shorten and (^)
maternal and paternal Anaphase 1 move slightly apart. (^)
chromosomes are located (^)
in each developing (^)
telophase nucleus. (^)
Telophase 1 Metaphase 1^
(^) Homologous pairs lie parallel (^)
to the equatorial plate, with (^)
(^) Chromosomes move toward opposite one set on either side. (^)
poles, with centromeres unsplit. (^)
(^) Secondary spermatocytes (^)
(each with haploid number of chromosomes) (^)
Second (^)
meiotic (^) Spermatozoa
division^
Chromosomes split
at centromeres,^
and sister chromatids
move apart.^
Spermatids
Figure 4- 15 Spermatogenesis occurring in the seminiferous tubules of the testes.
(^) ®
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