Podcast
Questions and Answers
Which of the following best describes the primary role of cervical mucus in fertilization?
Which of the following best describes the primary role of cervical mucus in fertilization?
- To provide an alkaline medium that facilitates sperm migration. (correct)
- To prevent the entry of sperm into the uterus.
- To induce the acrosome reaction of the sperm.
- To create an acidic environment that activates sperm.
What is the direct consequence of the acrosome reaction in fertilization?
What is the direct consequence of the acrosome reaction in fertilization?
- Fusion of the sperm and oocyte plasma membranes.
- Disintegration of the sperm nucleus and formation of the male pronucleus.
- Release of hyaluronidase to break down the corona radiata.
- Penetration of the zona pellucida by the sperm. (correct)
What is the significance of the cortical reaction in the fertilization process?
What is the significance of the cortical reaction in the fertilization process?
- It promotes the completion of meiosis II in the oocyte.
- It triggers the sperm to release acrosomal enzymes.
- It prevents polyspermy by altering the zona pellucida. (correct)
- It facilitates the fusion of sperm with the oocyte plasma membrane.
What event directly leads to the formation of the female pronucleus?
What event directly leads to the formation of the female pronucleus?
Which process directly precedes the alignment of chromosomes on the equatorial plane during fertilization?
Which process directly precedes the alignment of chromosomes on the equatorial plane during fertilization?
What is the chromosomal composition of a zygote?
What is the chromosomal composition of a zygote?
Which of the following dictates the sex of the zygote?
Which of the following dictates the sex of the zygote?
What is the direct result of karyogamy in the fertilization process?
What is the direct result of karyogamy in the fertilization process?
Flashcards
Capacitation
Capacitation
A process that occurs in the female reproductive tract, where sperm undergo biochemical changes, enabling them to bind to the zona pellucida and fertilize the egg.
Corona Radiata
Corona Radiata
The outer layer of cells surrounding the oocyte, which sperm must penetrate to reach the zona pellucida.
Zona Pellucida
Zona Pellucida
A protective glycoprotein layer surrounding the oocyte that prevents multiple sperm from entering.
Acrosomal Reaction
Acrosomal Reaction
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Fusion of Gametes
Fusion of Gametes
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Cortical Reaction
Cortical Reaction
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Zygote
Zygote
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Karyogamy
Karyogamy
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Study Notes
Sperm Migration and Capacitation
- Sperm travel from the cervix to the fallopian tubes
- Cervical mucus aids migration by providing an alkaline medium
- Biochemical changes in sperm plasma membrane enable sperm binding to the zona pellucida
- Capacitation occurs in the female reproductive tract
Pre-Fertilization Phenomena
- Sperm reaches the outer third of the fallopian tube (ampulla)
- Sperm releases hyaluronidase to break down intercellular connections in the corona radiata
- Sperm binds to ZP3 glycoprotein receptors on the zona pellucida
- Acrosome reaction: Acrosome releases hydrolytic enzymes (e.g., acrosin) to digest the zona pellucida
- A single spermatozoon penetrates the zona pellucida and fuses with the oocyte plasma membrane
Cortical Reaction and Meiosis II
- Cortical reaction: Exocytosis of cortical granules alters the zona pellucida, preventing polyspermy
- Secondary oocyte completes meiosis II upon sperm penetration
- Second polar body extruded
Formation of Pronuclei
- Sperm nucleus becomes the male pronucleus
- Oocyte nucleus becomes the female pronucleus
- Pronuclei migrate towards the cell center
- Pronuclei membranes disintegrate
- Chromosomes align on the equatorial plane of the spindle apparatus
Karyogamy (Fusion of Pronuclei)
- Results in the formation of a zygote with 44 autosomes and 2 sex chromosomes
Zygote Formation
- Zygote is the first cell of the new organism
- Contains a complete diploid set of chromosomes
- Composed of combined male and female genetic contributions
Sex Determination
- Sperm's sex chromosome (X or Y) determines the sex of the zygote
- X-sperm: Female (XX)
- Y-sperm: Male (XY)
Outcomes
- Zygote initiates its first mitotic division (cleavage) forming blastomeres
- Embryonic development begins.
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Description
This quiz covers the journey of sperm from the cervix to the fallopian tubes, including key biochemical changes that enable fertilization. Explore essential processes like capacitation, acrosome reaction, and the cortical reaction that prevent polyspermy. Test your knowledge on these vital pre-fertilization phenomena in human reproduction.
