Lecture 10 PDF: Human Development

Nervous System Development and Disorders Q: When do the brain and spinal cord begin to develop in the embryo? A: Around weeks 3 and 4. Q: What forms the brain and spinal cord during neural development? A: The neural tube. Q: What is the neural crest, and what does it develop into? A: Cells that d...

Nervous System Development and Disorders Q: When do the brain and spinal cord begin to develop in the embryo? A: Around weeks 3 and 4. Q: What forms the brain and spinal cord during neural development? A: The neural tube. Q: What is the neural crest, and what does it develop into? A: Cells that develop the peripheral nervous system, including spinal and cranial nerves. Q: What happens when the neural tube does not close properly? A: Neural tube defects, such as spina bifida. Spina Bifida and Related Disorders Q: What are the three main forms of spina bifida? A: Occulta, meningocele, and myelomeningocele. Q: What are common complications of spina bifida? A: Hydrocephalus, nerve development issues, paralysis, muscle weakness, and bladder dysfunction. Q: What is the most severe form of spina bifida? A: Myelomeningocele, where spinal fluid, meninges, and the spinal cord protrude through a vertebral defect. Cardiogenesis and Congenital Heart Defects Q: When does cardiogenesis begin, and how does the heart form? A: Cardiogenesis begins in week 3 with two parallel endothelial tubes that fuse into the heart chamber. Q: What is the ductus arteriosus, and what happens to it after birth? A: A fetal vessel connecting the pulmonary trunk to the aorta, which closes after birth to separate pulmonary and systemic circulation. Q: What are common congenital heart defects? A: Atrial septal defect, ventricular septal defect, patent ductus arteriosus, and pulmonary stenosis. Q: What are the four classifications of congenital heart defects? A: Lesions increasing or decreasing pulmonary blood flow, obstructive lesions, and mixed lesions. Lung Development and Prematurity Q: What are the five phases of lung development? A: Embryonic, pseudoglandular, canalicular, saccular, and alveolar. Q: Why is surfactant important for lung function? A: It reduces surface tension, preventing alveolar collapse and aiding in lung compliance. Q: What complications arise from premature births? A: Insufficient surfactant and immature lungs, leading to infant respiratory distress syndrome (IRDS). Q: How is IRDS treated in preterm infants? A: With corticosteroids, continuous positive airway pressure (CPAP), and surfactant therapy. Postnatal Changes and Homeostasis Q: What cardiovascular changes occur after birth? A: The ductus arteriosus and foramen ovale close, and pulmonary circulation increases. Q: Why do newborns have elevated heart and respiratory rates? A: To meet increased metabolic demands. Q: What is meconium, and when is it excreted? A: A collection of fetal bile, mucus, and cells excreted within the first day of life. Q: Why can’t neonates concentrate urine or regulate body temperature well? A: Due to immature kidney function and insufficient hypodermal fat, which improves over the first weeks of life.