Neuro L.6 Main Concepts Flashcards
What is the embryonic stage duration?
2-8 weeks
What does the ectoderm develop into?
Sensory organs, nervous system, epidermis
What does the mesoderm develop into?
Muscles, skeleton, dermis, excretory system, circulatory system
What does the endoderm develop into?
Gut, liver, pancreas, respiratory system
When does the neural tube develop?
Day 18-26
What happens on Day 20?
Abnormal events before 20 weeks may lead to major deformities of the nervous system.
What occurs on Day 21?
Neural plate folds into neural tube
When does the superior neuropore close?
Day 27
When does brain development begin?
Day 28
When does the inferior neuropore close?
Day 30
What happens at 1 month?
Motor roots of spinal cord become myelinated
What is the fetal stage duration?
9 weeks - birth
When does myelination begin?
4 months
What happens at 2 years old?
Nerves from cortex to motor neurons are myelinated
What happens at 3 years old?
Myelination stops
What happens at 4-5 years old?
Spinal cord stops growing
What happens at 16-18 years old?
Vertebral column stops growing
What is the flow of nervous system development?
Bilaminar disk (epiblast, hypoblast) → gastrulation → trilaminar disc (endoderm, ectoderm, mesoderm) → notochord → neural plate (from ectoderm) → neural fold → neural crest cells (PNS) → neural tube (CNS)
What does the inner layer of the neural tube develop into?
Gray matter
What does the outer layer of the neural tube develop into?
White matter
What are somites?
Paired blocks of mesoderm that form along the neural tube of a developing embryo
What does the anteromedial somite develop into?
Sclerotome (vertebrae/skull)
What does the posteromedial somite develop into?
Myotome
What does the lateral somite develop into?
Dermatome
