CNS Development Flashcards
When is the ICM observed?
The Inner Cell Mass is observed when the cells reach the blastocyte stage
What are the initial first two layers of the ICM?
The epiblast and hypoblast (once implanted)
At the stage where the Inner Cell Mass is differentiated into two layers, what is it called?
The bilaminar embryonic disc.
What is the layer of the bilaminar embryonic disc closest to the trophoblast (outer layer cells)?
The epiblast
What does the epiblast contribute to?
It will become the embryo, and contribute as well to some extraembryonic tissue
What is the layer of the ICM that borders the blastocoel cavity?
The hypoblast
What does the hypoblast become?
It is a temporary layer that plays a role in the yolk sac and laying out the body plan.
When is the single layered blastula reorganized? What is it organized into?
It goes through gastrulation to become a gastrula ( a 2 or 3 layered cell).
What is the end of gastrulation marked by?
The establishment of distinct cell lineages and the axes of the body
What are the three body axes (with examples?)
Frontal/Coronal plane - cut through the top of the head to remove the face
Transverse plane - separates the torso, divides the upper and lower halves of the body
Median Sagittal plane - Separates the left and right sides of the body
What are the 4 anatomical directions we use to define the embryo?
Doral/Ventral and Caudal/cranial
What are the three layers of the gastrula?
Endoderm, mesoderm, ectoderm
How are gastrula layers classified regarding the primitive groove?
Cells that invaginate through the primitive groove are called the endoderm, cells that are left behind make up the ectoderm, and cells in the middle are the mesoderm.
What gastrula cell layer is closest to the blastocoel cavity?
The endoderm
What layer of gastrula cells make up the brain and nervous tissue? What else does this layer differentiate into?
The ectoderm developed the brain and nervous system but also all the outer layers such as skin and sweat glands.
What type of organs arise from the mesoderm?
The ones that support movement and support ie. muscles, cartilage, bone, connective tissue
What organs arise from the endoderm layer?
Internal organs ie. GI system, endocrine systems, liver
What happens to the inside of the neural tube?
It becomes the ventricular system
What happens to the neural plate to form the neural tube?
The neural fold develops
What 3 types of structures do the fusion of the neural fold lead to?
The Neural tube, the neural crest, and somites
What arises from the neural tube?
The CNS
What is neurulation?
It is the process where the ectoderm folds inwards to form the neural tube
What does the neural crest form in development?
The PNS
What do somites form in development?
Vertebrae of spinal column and related muscle.