To refine the description by Exitrowaisle, the reading lights for the DC-10 center-section passengers are buried in that strip that runs down the ceiling, parallel to each aisle. That strip looks like a long waffle, and at each seat row, the indentation of the waffle contains reading lights, the other indentations (which is most of them) contain general illumination. The vanes of the waffles are set at an angle so that when you sit in the seat your eyes are not subject to the general illumination. This means that the ceiling strip looks different if you look aft vs. forward in the aircraft. I hope this makes sense, perhaps I can find some database pics that illustrate this.
The L-1011s did have air vents. There were little jets up there, under the stowage bins (window seats) and in the ceiling (center seats). The air was controlled by electric fans, and when you pushed a button in your seat you could adjust it from lo to hi. There would be a little click, like car a/c, when you went from one to the other. It was not a good design really, as you could never tell very easily what setting you were on. Also, it was impossible to reach up to the ceiling to aim the jets. Someone told me that TWA had a 'magic wand' that the f/a's could use to reach up there and adjust them. Another reason I love the Tristar! I did notice that Air Canada modified their system so that the amount of air was adjusted by screwing/unscrewing the nozzle instead of that goofy switch.