Respiratory
These are cells which line the trachea. It's a weird world down there.
Blood vessels
The blood in a human body would just about fill a basketball.
If you could visualise the shape of what you last ate, it may now be the shape of your capillaries, as your food has been broken down and distributed throughout your bloodstream.
The tiny capillaries on your tongue
Mark Smith, Human Body Macro-Micro Exhibit
Mark Smith, Human Body Macro-Micro Exhibit
Reddit community, Preserved human arteries. Found on /r/wtf but I think it belongs here.