Changes

*Meiotic phase: spermatocytes → spermatids

*Meiotic phase: spermatocytes → spermatids

*Differentiation phase (also known as spermiogenesis): spermatids → spermatozoa

*Differentiation phase (also known as spermiogenesis): spermatids → spermatozoa

Unlike the [[Oogenesis - Anatomy & Physiology|female production of gametes]] which occurs entirely before birth, with gamete maturation occurring in a pulsatile fashion after puberty, males produce gametes continuously from puberty onwards for the rest of their reproductive lives and the release of the gametes is constant.  

Unlike the [[Oogenesis - Anatomy & Physiology|female production of gametes]] which occurs entirely before birth, with gamete maturation occurring in a pulsatile fashion after puberty, males produce gametes continuously from puberty onwards for the rest of their reproductive lives and the release of the gametes is constant.  

As the germ cells progress through their stages of development they move slowly from the basement membrane of the tubules through the tight junctions between the Sertoli cells into the tubular lumen.

As the germ cells progress through their stages of development they move slowly from the basement membrane of the tubules through the tight junctions between the Sertoli cells into the tubular lumen.

==Stages of spermatogenesis==

==Stages of spermatogenesis==

Stem or A '''spermatogonia''' located in the basal region of the tubular epithelium undergo mitosis. The progeny of these divisions maintain their own numbers as well as giving rise to several interconnected B spermatogonia (the number of these arising from a single A spermatogonia is species dependent). B spermatogonia divide to give rise to primary (1^o) '''spermatocytes'''.  All descendants of a B spermatogonium remain connected by cytoplasmic bridges, forming a syncytium - like cell clone which undergoes synchronous development.

Stem or A '''spermatogonia''' located in the basal region of the tubular epithelium undergo mitosis. The progeny of these divisions maintain their own numbers as well as giving rise to several interconnected B spermatogonia (the number of these arising from a single A spermatogonia is species dependent). B spermatogonia divide to give rise to primary (1^o) '''spermatocytes'''.  All descendants of a B spermatogonium remain connected by cytoplasmic bridges, forming a syncytium - like cell clone which undergoes synchronous development.

===Meiotic phase===

===Meiotic phase===

The process of meiosis occurs over a long period, with prophase of the first meiotic division taking up to three weeks <ref name="Hess">Hess RA, Spermatogenesis, overview. In: Knobil E, Neil JD (eds.), Encyclopedia of Reproduction. New York: Academic Press; 1999: pp. 539–545</ref>

The process of meiosis occurs over a long period, with prophase of the first meiotic division taking up to three weeks <ref name="Hess">Hess RA, Spermatogenesis, overview. In: Knobil E, Neil JD (eds.), Encyclopedia of Reproduction. New York: Academic Press; 1999: pp. 539–545</ref>

===Differentiation phase===

===Differentiation phase===

For a diagrammatic representation refer to Figure 2.

For a diagrammatic representation refer to Figure 2.

==Hormonal Control of spermatogenesis==

==Hormonal Control of spermatogenesis==

Inhibin, testosterone and oestrogen feedback negatively on the anterior pituitary and hypothalamus to suppress secretion of gonadotrophic hormones (Figure 3).

Inhibin, testosterone and oestrogen feedback negatively on the anterior pituitary and hypothalamus to suppress secretion of gonadotrophic hormones (Figure 3).

==References==

==References==