Chapter Five The morphogenetic properties of mesenchyme

When structure-building cells crawl around as individuals, they are called mesenchyme.

Chapter Six The epithelial repertoire pp 181-237 (for Friday)

Epithelia are stuck regularly together, in continuous sheets
Epithelia are often barriers to water flow.

The outer layer of skin is epithelial; the lining of the digestive tract is epithelial; the wall of the blasocoel is an epithelium.
The innermost layer of blood vessels is a special kind of epithelium

Preface 2 pages

p. 1 intro definition approach

no single underlying theme, just a lot of mechanisms? And species?

p. 5 the plan 5 sections

Chapter two background; history
Haeckel   His   Roux   Driesch    D'Arcy Thompson Modeling morphogenesis

Every object has a shape. Some forces must have caused that shape.

Humans cut materials, boards for example, to create arbitrary shapes.
Those forces are external, and can create almost any arbitrary shape.

Animal shapes, cell shapes, bone shapes, tooth shapes etc. are caused by genes.

Embryology is partly about the forces that arrange cells, and shape cells so that they will have the correct anatomical shapes and structure.

When you watch an embryo develop, the shape changes you see are caused by various physical forces:

Cell contractions, water pressure (in the blastocoel, for example), osmotic swelling of cartilage

p. 15 footnote: an aspect to experimental embryology; it needs ideas, and almost any idea will do so long as it is experimentally disprovable.