...The plasma membrane of the spermatozoon is a highly sensitive structure to sudden temperature changes, due to its composition of fosfolipids and unsaturated fatty acids that provide its fluidity. spermatozoon communicates with external medium through plasma membrane by means signals and stimulus that guide it to capacitation and fertilization events  plasma membrane integrity is essential for the development of all these events. extreme temperatures can also cause damage to other sperm structures like acrosoma and mitochondrial sheet that leads to leak of ions, enzymes, ATP and ADN degeneration.

• Decreases and increases of temperature must be gradual.
• Temperature should not oscilate during the periods when it must be constant.
• A suitable preservation medium must be used.
• The border temperatures are 15 and 37ºC so we should never go down 15 nor go up 37ºC.:

• SEMEN COLLECTION: the ejaculate is collected at 37ºC in a vessel at the same temperature and it remains there until evaluation and dilution. It is advisable to collect with about 100 ml of extender also at 37ºC. This gives a higher volume and slows down the first temperature decrease. Time period of time between collection, dilution and the start of the temperature decrease must be as short as possible. collection room must be at a suitable temperature and near the laboratory. If it is necessary to go out, a portable fridge must be used.