What is the learning outcome for Lecture 2?
Understand normal and abnormal developmental themes commonly encountered in the human nervous system.
What are the main topics in this lecture?
Embryology, cellular populations, myelination, intrauterine growth stages, neural tube formation, ultrasound evaluation, and congenital abnormalities such as spina bifida and hydrocephalus.
What is prenatal development?
The process of embryonic and fetal growth from fertilization until birth.
What occurs during prenatal cellular differentiation?
Neural stem cells develop into neurons, glial cells, and ependymal cells associated with cerebrospinal fluid production.
List the stages of neurocytogenesis.
Stage 1: Undifferentiated matrix cells → Stage 2: Neuroblasts (neurons) → Stage 3: Glioblasts (glial cells).
When is myelination most active?
During the first two years of postnatal life, continuing into the third decade for intracortical fibers.
Which cells produce myelin in the CNS?
Oligodendrocytes.
List the stages of oligodendroglial development.
Progenitor → Pre-oligodendrocyte → Immature oligodendrocyte → Mature oligodendrocyte.
Why is myelination critical for development?
It ensures efficient neural conduction necessary for sensory-motor integration and coordination.
What are the three phases of intrauterine growth?
Cellular, embryonic, and fetal stages.
What are the three trimesters of pregnancy?
1st: Week 1–12; 2nd: Week 13–26; 3rd: Week 27–birth.
Why is ultrasound the imaging modality of choice during pregnancy?
It is noninvasive, radiation-free, cost-effective, and provides high-resolution real-time imaging.
When is the first ultrasound typically performed and for what purpose?
During the first trimester to confirm pregnancy and estimate gestational age.
When is the detailed fetal anatomy ultrasound performed?
During the second trimester (16–22 weeks) to detect birth defects or anomalies.
What additional uses does ultrasound have in later pregnancy?
Monitoring growth, assessing anomalies, and determining fetal position or heart rate.
What is gastrulation?
A process (days 7–10) where the embryonic disc forms three germ layers: ectoderm, mesoderm, and endoderm.
What are the derivatives of the three germ layers?
Ectoderm → skin & nervous system; Mesoderm → muscles, bones, heart; Endoderm → gut lining & internal organs.
What marks the beginning of gastrulation?
Formation of the primitive streak in the embryonic plate.
When does neural tube formation begin?
Around days 15–21 after fertilization.
What structures form from the neural tube?
The brain and spinal cord.
What is the notochord?
An early midline structure that provides axial support and later contributes to vertebral disc nuclei.
When does development of the CNS begin?
During the third week of intrauterine life.
What are the three layers of the developing neural tube?
Ependymal (germinal), mantle (gray matter), and marginal (white matter).
What separates sensory from motor regions in the developing neural tube?
The sulcus limitans divides the alar plate (sensory) from the basal plate (motor).
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1 - intro36
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2 - brain dev47
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TT 2; Neuro Pathology and Muscular Pathophysiology50
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3 - TBI : anatomy & mechanisms64
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3 - TBI; Clinical Manifestations & Management54
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4 - Stroke ; Etiology, Vascular Anatomy & Ischemic Cascade56
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4 - Stroke; Clinical Profiles, Management & Movement Disorders49
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MIDTERM LEARNING GUIDE38
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Final - Terminology100
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Final cheat sheet47
