Asked by: Hilal Kopcza
medical health infertility

What is the function of cortical granules?

Last Updated: 7th June, 2020

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The fertilization envelope is formed by the lifting of the vitelline envelope away from the egg plasma membrane. The cortical granules contain enzymes that aid in the detachment of the vitelline envelope, as well as other components that aid the osmotic swelling of the fertilization envelope away from the egg.

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Keeping this in consideration, what does the cortical granule do?

Cortical granules are regulatory secretory organelles (ranging from 0.2 um to 0.6 um in diameter) found within oocytes and are most associated with polyspermy prevention after the event of fertilization. This exocytosis of cortical granules is known as the cortical reaction.

Secondly, what is cortical granule reaction? Anatomical terminology. The cortical reaction is a process initiated during fertilization by the release of cortical granules from the egg, which prevents polyspermy, the fusion of multiple sperm with one egg.

Likewise, how do cortical granules prevent Polyspermy?

To prevent polyspermy, the zona pellucida, a structure that surrounds mammalian eggs, becomes impermeable upon fertilization, preventing the entry of further sperm. The structural changes in the zona upon fertilization are driven by the exocytosis of cortical granules.

What keeps a second sperm from entering the ovum?

After the sperm enters the cytoplasm of the oocyte (also called ovocyte), the tail and the outer coating of the sperm disintegrate and the cortical reaction takes place, preventing other sperm from fertilizing the same egg. The sperm nucleus then fuses with the ovum, enabling fusion of their genetic material.

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Kedarnath Tchekmasov

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What is the cortical reaction and why is it important?

What is the cortical reaction, and why is it important? a) The cortical reaction is the fusion of the egg cortex with the egg plasma membrane, which allows the sperm to enter. b) The cortical reaction is the entry of Ca2+ ions into the egg, which initiates development.

Atsushi Bertran

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What do cortical granules contain?

The fertilization envelope is formed by the lifting of the vitelline envelope away from the egg plasma membrane. The cortical granules contain enzymes that aid in the detachment of the vitelline envelope, as well as other components that aid the osmotic swelling of the fertilization envelope away from the egg.

Arely Majuelo

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What is a cortical response?

Cortical responses can be seen as the brain's attempt to minimize the free energy induced by a stimulus and thereby encode the most likely cause of that stimulus. Similarly, learning emerges from changes in synaptic efficacy that minimize the free energy, averaged over all stimuli encountered.

Inaya Galobart

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Why is Polyspermy bad?

Polyspermy is bad because, in addition to the extra set of chromosomes, a sea urchin sperm donates a centriole. The presence of additional centrioles during the first cell division will result in additional cleavage furrows and incorrect partitioning of the chromosomes (Fig.

Tzvetan Pohmel'Nyh

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Can multiple sperms penetrate an egg?

Physiological polyspermy happens when the egg normally accepts more than one sperm but only one of the multiple sperm will actually fuse its nucleus with the nucleus of the egg. Physiological polyspermy is present in some species of vertebrates and invertebrates.

Soad Siefermann

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Why is it important that only one sperm penetrate the egg?

Two mechanisms can operate to ensure that only one sperm fertilizes the egg. In many cases, a rapid depolarization of the egg plasma membrane, which is caused by the fusion of the first sperm, prevents further sperm from fusing and thereby acts as a fast primary block to polyspermy.

Lofti Tebas

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How is Polyspermy prevented?

Polyspermy is prevented by: modest sperm number; Fast block; Slow block. The acrosome is the tip of the sperm head. The acrosomal reaction is a change in the sperm that is common to many animals. (1) Receptor proteins (red) in the sperm plasma membrane contact the sea urchin jelly coat (vitelline layer).

Kaba Bezunartea

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What is zonal reaction?

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.

Jona Lerma

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What is Monospermic fertilization?

: involving or resulting from a single sperm cell monospermic fertilization.

Zdenka Smoler

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What is the cortical reaction quizlet?

The cortical reaction is exocytosis of the egg's cortical granules. Cortical granules are secretory vesicles that reside just below the egg's plasma membrane. This triggers fusion of the cortical granule membranes with the egg plasma membrane, liberating the contents of the granules to the extracellular space.

Sergo Barcena,

Pundit

Which enzyme is required for entry of sperm in egg?

As the sperm approach the egg, they bind to the zona pellucida in a process known as sperm binding. This triggers the acrosome reaction, in which the enzymes of the acrosome are freed. These enzymes then begin to digest the zona pellucida and allow the sperm to tunnel toward the egg's plasma membrane.

Ulyana Gubernator

Teacher

Do humans have fast block to Polyspermy?

The “oocyte membrane block” or so-called “fast block” to polyspermy occurs in seconds [6–8]; however, it was unlikely to be involved in “fast block” to polyspermy in the fertilization process in mammals [9].

Tova Tenoort

Teacher

What causes the formation of the fertilization envelope?

The fertilization envelope is formed by the lifting of the vitelline envelope away from the egg plasma membrane. The cortical granules contain enzymes that aid in the detachment of the vitelline envelope, as well as other components that aid the osmotic swelling of the fertilization envelope away from the egg.

Alfio Lezaun

Teacher

Zitouni Angorrilla

Teacher

What triggers the Acrosomal reaction?

The acrosome reaction allows the sperm by exocytotic release of acrosomal enzymes to penetrate the zona pellucida of the egg. The species-specific zona pellucida protein that serves as a sperm receptor also stimulates a series of events that lead to fusion between the plasma membrane and outer acrosomal membrane.

Jiale Osterweil

Reviewer

What is the purpose of the fertilization envelope?

At fertilization in most animals, cortical granules of the egg or oocyte secrete their contents, whose function it is to modify the extracellular matrix. This modified matrix then participates in the block to polyspermy and protection for early embryonic development.

Teolinda Zorrozua

Reviewer

What are the steps of fertilization and explain what cleavage is?

They occur via four essential stages in early animal development: Fertilization: the process of a single sperm cell combining with single egg cell to form a zygote. Cleavage: rapid, multiple rounds of mitotic cell division where the overall size of the embryo does not increase.

Mileidy Vitruk

Reviewer

What is the role of acrosome?

The function of the acrosome reaction is to help the sperm get through the egg's protective coat and to allow the plasma membranes of the sperm and egg to fuse. This places both haploid nuclei (one from the sperm and one from the egg) into the same cell, where they form the diploid genome of the new organism.

Oiana Silles

Reviewer

What is the function of this change in the jelly layer?

It prevents too many sperm from getting to the egg at the same time, because of its viscosity. Proteins in the jelly initiate the acrosome reaction in sperm so they are ready to fertilize the egg.