Fertilisation and Implantation in Humans

Questions and Answers

What is the primary purpose of the many sperm produced during fertilisation?

To fertilise multiple eggs at once

To create genetic diversity

To increase the chances of reaching the oviduct (correct)

To compete with other sperm for energy

During fertilisation, what is the chromosomal makeup of the zygote nucleus?

46 chromosomes, one set from each parent (correct)

92 chromosomes from multiple sperm

23 chromosomes from the mother

A mix of 23 chromosomes and variable amounts from sperm

What process prevents additional sperm from entering an egg after one has successfully penetrated?

The activation of the egg's enzymes

The movement of the egg away from the sperm

The formation of a protective shell

The alteration of the jelly coat (correct)

What occurs immediately after fertilisation of the egg?

The zygote nucleus begins copying its chromosomes Signup and view all the answers

What happens during the early stages of the zygote's development?

It becomes a hollow ball of cells Signup and view all the answers

How does the embryo obtain nutrients after implantation?

Via diffusion from blood vessels Signup and view all the answers

What is the role of ciliated epithelial cells in the oviduct?

To facilitate the movement of the embryo Signup and view all the answers

Which type of nuclear division occurs during cell division after fertilisation?

Mitosis Signup and view all the answers

What term describes the process where the embryo embeds itself into the uterine lining?

Implantation Signup and view all the answers

If no egg is present in the oviduct, what can still occur with the sperm?

They can survive for several days. Signup and view all the answers

Study Notes

Human Fertilisation

Millions of sperm are present in male semen; only a few reach the oviduct, where fertilisation occurs.
Sperm must navigate through the cervix and uterus to reach the oviduct, where an egg may be located.
The journey through the female reproductive tract is challenging, leading to high sperm production to ensure successful fertilisation.
If an egg is present, enzymes from the sperm's acrosome create a pathway through the egg's jelly coat for penetration.
Successful fertilisation occurs when the sperm's nucleus fuses with the egg's nucleus, forming a zygote nucleus containing 46 chromosomes (diploid).
The egg’s jelly coat undergoes a change to prevent additional sperm from entering, ensuring only one sperm fertilises the egg.
Sperm can survive in the female reproductive tract for 2-3 days, allowing fertilisation if intercourse happens just before ovulation.

Embryonic Development and Implantation

After fertilisation in the oviduct, the zygote begins cell division, initially forming a two-celled embryo, then progressing to four and eight cells.
Cell division becomes less regular over time, with some cells continuing to divide while others slow down or halt.
The embryo transforms into a hollow ball of cells as it moves towards the uterus, aided by peristaltic contractions and cilia in the oviduct.
The journey from the oviduct to the uterus may take several days.
Implantation involves the embryo embedding into the thickened uterine lining, rich in blood vessels.
Nutrients and oxygen are supplied to the embryo through diffusion from the uterine blood vessels, while waste products diffuse out in the opposite direction.

Key Concepts

Mitosis is the process of nuclear division that ensures genetic consistency in cells during growth and development.
Understanding the fertilisation and implantation processes is essential for comprehending early human development and reproductive biology.

Description

This quiz explores the processes of fertilisation and early development in humans. Understand how sperm travels to meet an egg and learn about the crucial steps leading to implantation in the uterus. Test your knowledge on these foundational concepts of human reproduction.