acrosome

physiology

Also known as: acrosomal cap, head cap

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Last updated

July 23, 2026

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The acrosome is a cap-like structure found at the anterior (front) of a sperm cell. It plays a crucial role in fertilization by releasing enzymes that help the sperm penetrate the egg. This process is part of spermatogenesis, the development of sperm cells within the male testes. The acrosome forms during the maturation of sperm cells, covering part of the sperm's head, which contains the genetic material.12

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fertilization
Sperm-egg association
The acrosome reaction of spermatozoa is a prerequisite for the association between a spermatozoon and an egg, which occurs through fusion of their plasma membranes. After a spermatozoon comes in contact with an egg, the acrosome, which is a prominence at the anterior tip of the…
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The acrosome reaction of spermatozoa is a prerequisite for the association between a spermatozoon and an egg, which occurs through fusion of their plasma membranes. After a spermatozoon comes in contact with an egg, the acrosome, which is a prominence at the anterior tip of the…
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sperm
…process is known as the acrosome reaction. The membrane of the sperm cell then fuses with that of the egg, and the sperm nucleus is conveyed into the egg.
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…process is known as the acrosome reaction. The membrane of the sperm cell then fuses with that of the egg, and the sperm nucleus is conveyed into the egg.
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sperm
…a cap known as the acrosome, which contains enzymes that help sperm to enter an egg. Only one sperm fertilizes each egg, even though 300,000,000 to 400,000,000 sperm are contained in an average ejaculation. Each egg and sperm produced has slightly different genetic information carried in the chromosomes; this accounts…
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…a cap known as the acrosome, which contains enzymes that help sperm to enter an egg. Only one sperm fertilizes each egg, even though 300,000,000 to 400,000,000 sperm are contained in an average ejaculation. Each egg and sperm produced has slightly different genetic information carried in the chromosomes; this accounts…
Read More

Ryuzo Yanagimachi
…first embryologists to study the acrosome reaction, the process by which a sperm penetrates the zona pellucida, allowing it to bind to the plasma membrane of an egg. He determined in 1970 that only sperm that had undergone the reaction could bind to the plasma membrane. A 1976 study conducted…
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…first embryologists to study the acrosome reaction, the process by which a sperm penetrates the zona pellucida, allowing it to bind to the plasma membrane of an egg. He determined in 1970 that only sperm that had undergone the reaction could bind to the plasma membrane. A 1976 study conducted…
Read More