bio 105 - fertilization and development 2

Differentiation occurs due to changes in...

Gene regulation

As the cell divides, different transcription, programs are turned on via signals from the environment, causing cells to begin doing what?

Expressing different proteins.

What are established by the end of gastrulation?

The major body axes.

What forms along what will be the dorsal side of the embryo near the end of gastrulation in vertebrates (animals with a backbone)?

The notochord forms.

Neurulation leads to the development of what?

It leads to the development of the spinal cord

Neurulation leads to the differentiation of _____ _____ in the developing embryo?

Body regions

Neurulation is restricted to what kind of organisms?

Vertebrates (those with backbones).

What is neurulation induced by?

Signaling molecules released by the notochord, which runs the length of the dorsal side of the embryo.

When does the notochord form?

After gastrulation is complete.

Signals from notochord cause ______ _____ of ectoderm at the neural plate.

Inward folding

What comprises the rest of pre-natal development?

Growth and organogenesis.

Stages of development

zygote/Fertilization, cleavage, blastula, gastrula, neurulation, organogenesis

Growth requires raw materials and energy to drive anabolic reactions. How do humans get this energy?

This must be provisioned by the mother (in mammals like humans this occurs mostly via the placenta).

What can organogenesis include?

It can involve substantial migration of cells within the developing embryo in order to create an organ with the appropriate structure. Apoptosis may also be involved, and it may be just as important as cell profile ratio and migration in creating the appropriate final structure of an organ.

cleavage

the rapid cell divisions that follow fertilization, leading to the formation of a multi cellular embryo.

zygote

fertilized egg cell formed after sperm and egg cell unite

blastula

a hollow ball of cells formed after cleavage

gastrula

stage where the embryo undergoes significant folding to form 3 distinct germ layers (ectoderm, mesoderm, endoderm)

neurulation

the process in which the neural tube forms from the ectoderm, giving rise to the central nervous system

organogenesis

the formation of organs from the 3 germ line layers