Pulmonary alveolus thin fluid coating within all alveoli. The fluid coating is produced by the body in order to facilitate the transfer of gases between blood and alveolar air. The surfactant is produced by the type II cells which are the most numerous cells in the alveoli, yet do not cover as much surface area as the squamous alveolar cells (a squamous epithelium). Type II cells also repair the endothelium of the alveolus when it becomes damaged. Insufficient surfactant in the alveoli can contribute to atelectasis (collapse of part or all of the lung). Without pulmonary surfactant, atelectasis is a certainty; however,
The Part Played by Labour in the Transition from Ape to Man a dialectical relationship with the human body. Specifically, Engels emphasizes the importance of humans’ opposable thumbs and phonetically dynamic mouths, which enabled them to articulate complex forms of language over time. In that respect, the essay challenged the prevailing philosophy of Cartesian dualism, which drew a stark division between mind and body. Marx and Engels had both alluded to this notion in previous writings, for instance in their first collaborative work, "The Holy Family", in which they wrote, “Body, being, substance are but different terms for the same reality. It is impossible to separate thought from matter that thinks.” However,