Mature ovum

Definition

A mature ovum, also known as a secondary oocyte, is the female gamete that has completed the first meiotic division and is ready for fertilization. This process occurs during oogenesis and is a crucial part of the ovarian cycle, leading to the potential for reproduction. The mature ovum is characterized by its large size, nutrient-rich cytoplasm, and the presence of the zona pellucida, a protective glycoprotein layer that surrounds it.

5 Must Know Facts For Your Next Test

1. The mature ovum is released from the ovary during ovulation, typically around day 14 of a woman's menstrual cycle.
2. Mature ova have a limited lifespan and can be fertilized for about 12 to 24 hours after ovulation.
3. Only one mature ovum is typically released during each menstrual cycle, though multiple follicles may develop.
4. The zona pellucida not only protects the mature ovum but also plays a key role in sperm binding and fertilization.
5. Hormones such as luteinizing hormone (LH) trigger the final maturation and release of the ovum from the ovarian follicle.

Review Questions

• How does the process of oogenesis lead to the formation of a mature ovum, and what are its key characteristics?
  • Oogenesis begins with the proliferation of oogonia in the ovaries, which then develop into primary oocytes that enter meiosis. During this process, primary oocytes complete their first meiotic division to become secondary oocytes, or mature ova. Key characteristics of a mature ovum include its large size compared to other cells, a rich cytoplasm for supporting early development, and the presence of the zona pellucida which protects it and facilitates fertilization.
• Discuss the hormonal regulation involved in the maturation and release of a mature ovum during the ovarian cycle.
  • The maturation and release of a mature ovum are primarily regulated by hormones such as follicle-stimulating hormone (FSH) and luteinizing hormone (LH). FSH stimulates follicle growth and estrogen production by developing follicles. A surge in LH levels triggers ovulation, leading to the release of the mature ovum from its follicle. This hormonal interplay ensures that a mature ovum is available for fertilization at optimal times during the menstrual cycle.
• Evaluate the significance of the mature ovum in reproductive biology and its impact on fertility.
  • The mature ovum plays a critical role in reproductive biology as it is essential for fertilization and subsequent embryo development. Its quality, including genetic integrity and cytoplasmic health, significantly affects fertility outcomes. Factors such as age, hormonal balance, and overall health can influence oocyte quality and availability. Understanding the importance of the mature ovum in fertility helps inform reproductive health practices and treatments for infertility.

Related terms

Oogenesis:

The process of female gamete formation that occurs in the ovaries, involving several stages of development from primordial follicles to mature ova.

Follicle: A structure in the ovary that contains the developing oocyte and is responsible for producing hormones such as estrogen.

Fertilization: The union of a mature ovum with a sperm cell, resulting in the formation of a zygote, which can develop into an embryo.