DO NOW: Explain in your own words the changes that occur to chromosome number during fertilization.

DO NOW:Explain in your own words the changes that occur to chromosome number during fertilization

The process of the fusion/uniting of the egg cell and the sperm cell

During fertilization …… the chromosome number is restored by a process called recombination

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Recombination is the additional mixing of genetic material from the sperm and the egg creating a UNIQUE combination

of genes

At this point the zygote has all needed chromosomes to be a human

Blastula

Cleavage

Zygote Blastula Gastrula

A hollow ball of cells

A three layered cluster of cells

Differentiationa.k.a. specialization

The process that transforms developing cells into specialized cells with different structures and functions

Before differentiation occurs, the cells are stem cells

an event in which the embryo adheres to the

wall of uterus. In order for the fetus to receive the oxygen and the nutrients from the mother to be able to

grow.

Fetal Life Support:

Includes:

Placenta

Amniotic sac

Umbilical cord

*Morphing embryo

Placenta:A flat organ that attaches to the inside of the uterus

and connected to the fetus by the umbilical cord.

Functions:• Transfer gasses• Transport nutrients• Excretion of wastes• Formation of a barrier

* The blood of the mother and the fetus do not mix

Human Fetus at 10 weeks

The Amniotic SacThe Amniotic Sac

•The fetus is in a fluid filled sac that helps protect it.

•When a woman’s “water breaks,” it means that this sac has ruptured

The umbilical cord (also called birth cord) is a tube that connects a developing embryo or fetus to the placenta.

Aim: How does a mother’s choices affect her offspring?

Prenatal development is greatly affected by anything circulating in the maternal blood

The Mother’s Choices Can Affect the FeWhat are some things that can affect

the fetus?s• Drugs

• Alcohol• Tobacco• Poor diet• Toxic substances• Infections (German measles, AIDS)

The Mother’s Choices Can Affect the Fetus

•The embryo is most susceptible to harm

during the first trimester

Alcohol abuse causes changes in the fetus called

fetal alcohol syndrome

•About 5% of newborns in the United States have a clinically significant birth defect, accounting for about 15% of deaths of newborns

Reproductive Technology:Reproductive Technology:

Amniocentesis:

**Reproductive Technology:Reproductive Technology:

• Hormone Regulation: to help women get pregnant

• In-vitro fertilization: Eggs are extracted from a woman’s ovaries and fertilize them with sperm in the laboratory. The fertilized eggs are then implanted in the uterus.

http://embryology.med.unsw.edu.au/

The Birth Process

Labor and Delivery

• NOVA Online | Life's Greatest Miracle | Watch the Program