Development of the Nervous System and Heart: lecture 10

Study Notes

The brain and spinal cord begin to develop in the embryo around week 3 and 4.
The neural tube forms the brain and spinal cord.
The neural crest is a group of cells that develop into components of the peripheral nervous system, including spinal and cranial nerves.
Neural tube defects, such as spina bifida, occur when the neural tube does not close properly.

There are three main forms of spina bifida: occulta, meningocele, and myelomeningocele.
Common complications of spina bifida include hydrocephalus, nerve development issues, paralysis, muscle weakness, and bladder dysfunction.
Myelomeningocele, the most severe form, involves spinal fluid, meninges, and the spinal cord protruding through a vertebral defect.

Cardiogenesis, the development of the heart, begins in week 3 with two parallel endothelial tubes that fuse into the heart chamber.
The ductus arteriosus is a fetal vessel connecting the pulmonary trunk to the aorta, which closes after birth to separate pulmonary and systemic circulation.

Common defects include atrial septal defect, ventricular septal defect, patent ductus arteriosus, and pulmonary stenosis.
Congenital heart defects can be classified into four categories: lesions increasing or decreasing pulmonary blood flow, obstructive lesions, and mixed lesions.

Lung development occurs in five phases: embryonic, pseudoglandular, canalicular, saccular, and alveolar.
Surfactant, a substance that reduces surface tension, is essential for proper lung function.
Premature births can lead to complications such as insufficient surfactant and immature lungs, resulting in infant respiratory distress syndrome (IRDS).
Treatment for IRDS includes corticosteroids, continuous positive airway pressure (CPAP), and surfactant therapy.

After birth, the ductus arteriosus and foramen ovale close.
Pulmonary circulation increases after birth.
Newborns have elevated heart and respiratory rates to meet increased metabolic demands.