Polyspermy
Polyspermy[edit | edit source]
Polyspermy is a phenomenon that occurs during the fertilization process when an egg is fertilized by more than one sperm. This can lead to abnormal development and is generally prevented by various mechanisms in sexually reproducing organisms.
Mechanisms of Polyspermy Prevention[edit | edit source]
In most species, polyspermy is prevented by a series of mechanisms that ensure only one sperm fertilizes the egg. These mechanisms can be broadly categorized into two types: fast block and slow block.
Fast Block to Polyspermy[edit | edit source]
The fast block to polyspermy occurs immediately after the first sperm fuses with the egg. This involves a rapid depolarization of the egg's plasma membrane, which prevents additional sperm from fusing with the egg.
Slow Block to Polyspermy[edit | edit source]
The slow block to polyspermy involves the cortical reaction, where cortical granules release their contents into the space between the plasma membrane and the zona pellucida. This leads to changes in the zona pellucida that prevent further sperm from penetrating the egg.
Types of Polyspermy[edit | edit source]
Polyspermy can be classified into two main types: pathological polyspermy and physiological polyspermy.
Pathological Polyspermy[edit | edit source]
Pathological polyspermy occurs when multiple sperm fertilize an egg, leading to an abnormal zygote with too many chromosomes. This often results in developmental failure and is typically lethal.
Physiological Polyspermy[edit | edit source]
Physiological polyspermy is a controlled process observed in some species, such as birds and reptiles, where multiple sperm enter the egg, but only one sperm's genetic material fuses with the egg's nucleus. The additional sperm contribute to the activation of the egg but do not contribute genetically.
Consequences of Polyspermy[edit | edit source]
The primary consequence of polyspermy is the formation of a polyploid zygote, which usually cannot develop properly. In most cases, the resulting embryo is non-viable due to the imbalance in genetic material.
Related Pages[edit | edit source]
Search WikiMD
Ad.Tired of being Overweight? Try W8MD's physician weight loss program.
Semaglutide (Ozempic / Wegovy and Tirzepatide (Mounjaro / Zepbound) available.
Advertise on WikiMD
|
WikiMD's Wellness Encyclopedia |
| Let Food Be Thy Medicine Medicine Thy Food - Hippocrates |
Translate this page: - East Asian
中文,
日本,
한국어,
South Asian
हिन्दी,
தமிழ்,
తెలుగు,
Urdu,
ಕನ್ನಡ,
Southeast Asian
Indonesian,
Vietnamese,
Thai,
မြန်မာဘာသာ,
বাংলা
European
español,
Deutsch,
français,
Greek,
português do Brasil,
polski,
română,
русский,
Nederlands,
norsk,
svenska,
suomi,
Italian
Middle Eastern & African
عربى,
Turkish,
Persian,
Hebrew,
Afrikaans,
isiZulu,
Kiswahili,
Other
Bulgarian,
Hungarian,
Czech,
Swedish,
മലയാളം,
मराठी,
ਪੰਜਾਬੀ,
ગુજરાતી,
Portuguese,
Ukrainian
Medical Disclaimer: WikiMD is not a substitute for professional medical advice. The information on WikiMD is provided as an information resource only, may be incorrect, outdated or misleading, and is not to be used or relied on for any diagnostic or treatment purposes. Please consult your health care provider before making any healthcare decisions or for guidance about a specific medical condition. WikiMD expressly disclaims responsibility, and shall have no liability, for any damages, loss, injury, or liability whatsoever suffered as a result of your reliance on the information contained in this site. By visiting this site you agree to the foregoing terms and conditions, which may from time to time be changed or supplemented by WikiMD. If you do not agree to the foregoing terms and conditions, you should not enter or use this site. See full disclaimer.
Credits:Most images are courtesy of Wikimedia commons, and templates, categories Wikipedia, licensed under CC BY SA or similar.
Contributors: Prab R. Tumpati, MD
