Will you let my acrosome react with your zona pellucida?
It plays an essential role during fertilization, by making spermatozoa able of penetrating the zona and capable of fusing with the egg plasma membrane. Zona pellucida is the natural inducer of the acrosome reaction.
What happens during the acrosome reaction?
The acrosome reaction is the exocytosis of the acrosome, or the fusion of the acrosomal membrane with the sperm’s plasma membrane. This process releases the acrosomal contents to the outside of the sperm and exposes the inner acrosomal membrane proteins on the sperm’s outer plasma membrane.
What is the zona pellucida reaction?
The zona pellucida is seen as a thick clear girdle surrounded by the cells of the Corona radiata. Anatomical terminology. The cortical reaction is a process initiated during fertilization that prevents polyspermy, the fusion of multiple sperm with one egg.
How is the acrosome involved in the digestion of the zona pellucida?
The sperm first burrow through the cells of the corona radiata. Then, upon contact with the zona pellucida, the sperm bind to receptors in the zona pellucida. This initiates a process called the acrosomal reaction in which the enzyme-filled “cap” of the sperm, called the acrosome, releases its stored digestive enzymes.
What triggers the acrosome reaction in mammals?
It is now known that in a certain sense, this phenomenon is physiologically normal across mammalian species. The acrosome reaction is induced by passage through the cumulus oophorus cells, mediated by the hormones they secrete (such as progesterone, LPA, LPC).
What do you mean by acrosome reaction and implantation?
The acrosomal reaction is the process of the egg and sperm cells fusing together during fertilization. Acrosomal reactions are an essential step of conception, and any abnormality can prevent fertilization and cause infertility.
What is the definition of Zona reaction?
Definition. Zona reaction refers to a modification of the zona pellucida in response to fertilization, which alters the solubility and binding properties of the zona pellucida, and leads to a slow block to polyspermy.
What enzyme is released by acrosome?
In Eutherian mammals the acrosome contains degradative enzymes (including hyaluronidase and acrosin). These enzymes break down the outer membrane of the ovum, called the zona pellucida, allowing the haploid nucleus in the sperm cell to join with the haploid nucleus in the ovum.
What happens to the zona pellucida during Fertilisation?
In humans, five days after the fertilization, the blastocyst performs zona hatching; the zona pellucida degenerates and decomposes, to be replaced by the underlying layer of trophoblastic cells. The zona pellucida is essential for oocyte growth and fertilization.
What enzymes do acrosome contain?
What happens to the plasma membrane during the acrosome reaction?
As the acrosome reaction progresses and the sperm passes through the zona pellucida, more and more of the plasma membrane and acrosomal contents are lost. By the time the sperm traverses the zona pellucida, the entire anterior surface of its head, down to the inner acrosomal membrane, is denuded.
What is the purpose of the acrosome reaction?
The acrosome reaction is a crucial step during gamete interaction in all species, including man. It allows spermatozoa to penetrate the zona pellucida and fuse with the oocyte membrane. Spermatozoa unable to undergo the acrosome reaction will not fertilize intact oocytes.
What happens to the exposed acrosome during the spermatozoon reaction?
After the acrosome reaction, the exposed acrosome becomes the head of the spermatozoon. This is covered in the acrosome reaction by proteolytic enzymes. These digest a path through the zona pellucida through which the spermatozoon passes.
What is the acrosome reaction in amphibians?
The acrosome reaction in amphibians more closely resembles that of mammals, as fusion of the acrosomal vesicle and the sperm plasma membrane leads to exposure of the inner acrosomal membrane without formation of an acrosomal process (Ueda et al., 2007; Ueda, Yoshizaki, & Iwao, 2002 ).