Lung histology (12.5X)

This is a piece of a lung. At this low magnification it looks like a sponge. This "sponge" is mostly filled with air and a whole lot of other stuff. But the small "air- sacks" that make up most of the parenchyme of the lung are the alveoli. There are some larger and smaller circular structures visible. That is the a couple of bronchi and bronchioles. If the contens of the circular structures have a pinkish hue, there is a high likelyhood you're looking at an artery. The visceral pleura encases the lung. The visceral pleura is a single layer of squamous epithelium (mesothelium) with some connective tissue underneath.

Magnify for more detail and information on the structures and cells of the lung.