Human fertilization and early development | High school biology | Khan Academy | Summary and Q&A

60.3K views
December 11, 2017
by
Khan Academy
YouTube video player
Human fertilization and early development | High school biology | Khan Academy

TL;DR

Fertilization is the process of the sperm cell fertilizing the egg cell, resulting in the formation of a zygote, which then undergoes cell division to develop into an embryo and eventually a fetus.

Install to Summarize YouTube Videos and Get Transcripts

Questions & Answers

Q: What is fertilization?

Fertilization is the process in which a sperm cell from the father joins with an egg cell from the mother, resulting in the formation of a zygote that has the combined genetic information of both parents.

Q: How does cell division occur after fertilization?

After fertilization, the zygote starts to divide through mitosis. It first splits into two cells, then four, and so on, leading to the formation of a morula consisting of 16 cells. This division continues until a blastocyst with hundreds of cells is formed.

Q: What is the difference between an embryo and a fetus?

An embryo is the term used to describe the developing organism from fertilization until around the 12th week of gestation. Afterward, it is considered a fetus. The transition is not well-defined, but the 12-week mark is commonly used.

Q: When does viability occur during pregnancy?

Viability refers to the point in pregnancy when there is a significant chance of survival if the baby were to be born prematurely. It is generally considered to be around the 24th week of gestation, although there is a roughly 50% survival rate at the sixth month.

Summary & Key Takeaways

  • Fertilization occurs when a sperm cell from the father comes into contact with and penetrates the egg cell from the mother, resulting in the creation of a zygote.

  • The zygote undergoes cell division through mitosis, splitting into two cells, then four, and so on. After several days, it forms into a blastocyst consisting of hundreds of cells.

  • The blastocyst continues to divide and develop, transitioning to an embryo, which eventually becomes a fetus by around the 12th week of gestation.

Share This Summary 📚

Summarize YouTube Videos and Get Video Transcripts with 1-Click

Download browser extensions on:

Explore More Summaries from Khan Academy 📚

Summarize YouTube Videos and Get Video Transcripts with 1-Click

Download browser extensions on: