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Testes and Epididymis - Anatomy & Physiology (view source)
Revision as of 19:31, 13 August 2008
, 19:31, 13 August 2008no edit summary
=The Epididymis=
=The Epididymis=
==Introduction==
==Introduction==
The Epididymis provides the environment for final maturation of spermatozoa. It is here that they aquire motility and fertility. The Epididymal duct is very long, between 30-60 meters. It is devided functionally into 3 regions; the Caput (head), Corpus (body) and Cauda (tail). The caput of the epididymis is connected to the efferent ducts of the testes. The Cauda connects to the Ductus Deferens of the spermatic cord.
==Structure & Function==
==Structure & Function==
'''Caput (head)'''
*Fluid secreted in the rete tubules of the testes is reabsorbed here and epididymal fluid is secreted. This fluid secretion is important in order to facilitate movement of the sperm through the epididymis.
'''Corpus (body)'''
*Nuclear chromatin condenses via the addition of di-sulphide bridges. This condensation stabilises the nuclear material and can be observed histologically as darker staining material.
*Stabilising surface proteins are added to the sperm membranes.
*Sperm aquire fertility by the addition of membrane receptors to female tract ligands. This enables them to bind to the [[Zona Pellucida]] and oocyte membranes.
*Sperm cells are dehydrated.
*Sperm aquire forward motility.
'''Cauda (tail)'''
*Sperm metabolic activity is depressed in order to prolong life.
*Sperm are stored here until ejaculation.
==Histology==
==Histology==
The Epididymal duct is surrounded by smooth muscle fibers. These fibers contract rhythmically facilitating sperm movement through the duct.
'''Caput'''
*Columna epithelium with basal nuclei.
*Small steriocillia present, these have an absorbtive function
'''Corpus'''
*Low columna epithelium with very prominant stereocillia.
*Small groups of sperm can be observed within the lumen of the duct.
'''Cauda'''
*Cuboidal/ Low columna epithelium. However, unlike the caput and corpus regions of the epididymis the cauda epithelium has no stereocillia.
*Large numbers of sperm observable here as this is the site of sperm storage within the testes.