The correct spelling of "cortical granule" is /ˈkɔːtɪkəl ˈɡrænjuːl/. The word "cortical" refers to the cortex, which is the outer layer of an organ or structure. "Granule" refers to a small particle or grain. Therefore, cortical granules are small particles found in the cortex of cells. These granules are involved in vital processes such as fertilization and cell division in animals. Proper spelling and pronunciation of scientific terms like cortical granule is essential to ensure effective communication in the scientific community.
A cortical granule refers to a small, membrane-bound organelle found in the cytoplasm of oocytes and eggs. It is predominantly present in the outer region or cortex of the cell, explaining its name. As a component of the cortical reaction, the granules play a crucial role in fertilization processes and early embryonic development.
These granules are formed and matured within the Golgi apparatus and then transport to the cortex region of the oocyte or egg, where they remain dormant. Upon the fusion of a sperm cell with the egg membrane during fertilization, the cortical granules undergo exocytosis, releasing their content outside the cell. The released contents are primarily enzymes and proteins that modify the extracellular environment surrounding the egg, preventing polyspermy (the fertilization by more than one sperm) and altering the zona pellucida, a glycoprotein-rich matrix surrounding the egg. These modifications create a fertilization barrier to prevent other sperm cells from entering the egg, contributing to the establishment of a monospermic zygote.
Cortical granules are vital in species that undergo external fertilization, such as many marine invertebrates. As these granules play a central role in early embryonic development, any dysfunction or aberration in their formation, transport, or exocytosis can lead to embryo abnormalities or infertility. Hence, the study and understanding of cortical granules are significant to elucidate the mechanisms underlying fertilization and embryogenesis.
The word "cortical granule" derives from the combination of two terms: "cortical" and "granule".
1. Cortical: The term "cortical" is derived from the Latin word "cortex", meaning "bark" or "outer layer". In biology, it is often used to refer to the outer layer or region of an anatomical structure. In the case of a cell, the term cortical is used to describe the outer layer surrounding the cell's cytoplasm.
2. Granule: The word "granule" is derived from the Latin term "granulum", which means "small grain" or "particle". In biology, it generally refers to small particles or structures present within cells.
Therefore, the term "cortical granule" refers to small particles or granules that are present in the outer layer or cortex of a cell.