Atelectasis Atelectasis Atelectasis is the collapse or closure of a lung resulting in reduced or absent gas exchange. It may affect part or all of a lung. It is usually unilateral. It is a condition where the alveoli are deflated down to little or no volume, as distinct from pulmonary consolidation, in which they are filled with liquid. It is often called a collapsed lung, although that term may also refer to pneumothorax. It is a very common finding in chest x-rays and other radiological studies, and may be caused by normal exhalation or by various medical conditions. Although frequently described
Development of the nervous system in humans Development of the nervous system in humans The development of the nervous system in humans involves the studies of neuroscience and developmental biology to describe the cellular and molecular mechanisms by which complex nervous systems emerge during embryonic development and develop throughout life. Some landmarks of embryonic neural development include the birth and differentiation of neurons from stem cell precursors (neurogenesis), the migration of immature neurons from their birthplaces in the embryo to their final positions, outgrowth of axons from neurons and guidance of the motile growth cone through the embryo towards postsynaptic partners, the generation of synapses between these