 Allergies! [25]
Allergy is a disorder of the immune system often also referred to as atopy.
Antidepressants [24]
An antidepressant is a psychiatric medication used to alleviate mood disorders, such as major depression and dysthymia.
Arthritis [23]
Arthritis is a group of conditions involving damage to the joints of the body.
Cancer [28]
Cancer is a class of diseases in which a group of cells display uncontrolled growth
Cardio & Blood [1]
Risk factors for heart disease: infections
Cholesterol [3]
A fat-like substance called a lipid. It is used to build cell membranes, hormones and bile acids
Diabetes [20]
The inability of the body to produce, or the inability to metabolize, the human hormone insulin; Diabetes insipidus, usually a disorder of the ...
Epilepsy [9]
Epilepsy is a common chronic neurological disorder characterized by recurrent unprovoked seizures
Gastrointestinal [4]
The digestive tract is the system of organs within multicellular animals that takes in food...
General Health [54]
The infant, child or young person?s current health condition
Herbal [30]
Herbal tea, herbal medicine
Hormonal [26]
Hormones - Proteins produced by organs of the body that trigger activity in other locations.
Men's Health [2]
For men on fitness, health, sex, caree
Pain relief [23]
Pain management is the medical discipline concerned with the relief of pain.
Skin care [23]
The skin is the outer covering of the body
Weight Loss [29]
Loss of body weight by dieting or due to various easting disorders or medical conditions.
Women's Health [31]
Find information on women's health issues, and lifestyle at the Women's Health
Fresh material  What are symptoms of endometriosis: dysmenorrhoea
→ More
Solutions to infertility: what you can do to help yourself
→ More
Endometriosis: the burden of guilt
→ More
Endometriosis: about suspected diagnosis
→ More
What are symptoms of endometriosis
→ More
The most popular materials [1561 view]
What are symptoms of endometriosis: dysmenorrhoea → More
[1519 view]
Prostaglandins—the new hormones → More
[1369 view]
Hysterectomy: prolapse → More
[1367 view]
Factors affecting fertility: environmental hazards → More
[1308 view]
Solutions to infertility: what you can do to help yourself → More
Awaiting moderation 692 Article |
Male fertility: why are so many sperm needed? MALE FERTILITY: WHY ARE SO MANY SPERM NEEDED?
The count is a measurement of how many sperm there are per milliliter, there should be at least 20 million. And yet a man might have a volume of 4ml, which would equal 80 million sperm in that one sample. As it only takes one sperm to fertilise the egg, and indeed nature tries to prevent any other sperm entering once one has penetrated the inner surface, why are millions produced in each ejaculate? As with other aspects of nature, abundance is the rule. Many more seeds are produced from a plant than will actually get a chance to germinate. It is the same with frog spawn where, from that enormous mass, hundreds of tadpoles can emerge but only a small proportion will eventually become frogs. Nature always works on the principle of 'survival of the fittest', basing her calculations on the fact that, from the huge number produced, be it seeds or sperm, many are going to die off en route.
It is estimated that only a small fraction of sperm will actually reach the egg (as few as 100), as the sperm need to swim up the vagina, through the cervix and up the fallopian tubes. Normally only one egg is released and this egg will travel down one fallopian tube, so half of the sperm that are left after the long journey could be traveling up a tube with no egg in it.
When they finally meet the egg, a number of sperm will surround it. On the front of the sperm's head is the acrosomal head cap which contains certain degradative enzymes to help dissolve the cumulous cells surrounding the egg. The combined action of a number of sperm helps with this dissolving process but only one sperm actually gets through the next layer, the zona pellucida. As soon as the egg is penetrated, rapid changes take place in its outer layer and no other sperm can get through.
Intriguing facts about sperm
• A sperm lashes its tail 800 times to travel 1 millimeter.
• Sperm reach the woman's fallopian tubes 30-60 minutes after ejaculation.
• Sperm are produced at an average of 1,500 per second from each testicle.
• In the right conditions, sperm can live up to five days.
• One sperm can swim 3 millimeters per second.
*2/73/5*
MEN’S HEALTH
«Online Pharmacy no Prescription»
 Print
Viewed: 271
| Keywords for this page: Male fertility: why are so many sperm needed? |
|
|
