Notes

You'll need to know the different parts of the neural tube.
And what each of them becomes in the adult nervous system.
You'll need to know the parts of the neuron & how they function.
You'll need to know the parts of the eye and how they arise.
You'll need to know how various glands & sensory organs develop.
You'll need to know the various organs formed by mesoderm.
You'll need to know how neck structures are formed.
Specifically which of them comes from which germ layer.
And you'll need to know about embryo’s heart & circulatory system.
“Membranes” refers to extraembryonic membranes of birds & mammals.
Since this is the 4th test, I'm going to summarize several major themes.
I will mention those during this lecture and the next 2 lectures.
“Epithelial layers” concerns stratification of the neural tube & the eye.
I will mention cell types that have peculiarities that are worth noting.

This slide picks up where the process of neurulation left off.
The neural tube is hollow, with holes at either end = neuropores.
Those neuropores seal over completely to create a cylinder.
This cylinder can be blown up like a balloon by fluid pressure.
In this diagram, we're seeing the front end of the neural tube.
It is from a human embryo at 4 weeks after fertilization.
It consists of bulges, constrictions, and bends.
There are 2 prominent bends called “flexures”.
The one at the front = “cephalic” flexure, meaning head.
The one at the back = “cervical” flexure, meaning neck.
We use the Latin term “encephalon” [E] = brain = “inside the head”.
“Pros[E]” = forebrain; “Mes[E]” = midbrain; and “Rhomb[E]” = hindbrain .
Those regions are shown in cross-section in the diagram at the right.
The bulges growing out laterally from the Pros[E]  cerebral hemispheres.
The rear end behind the Rhomb[E]  front part of spinal cord.
The remainder of the spinal cord is not shown in this diagram.