Here are some links from a animal physiology class at Simon Fraser University that provide a pretty nice description of the mechanisms that influence respiration. Looking through the slides, I was able to relate a lot of the information to stuff that has been posted here and personal experience. The slides also specifically mention human diving capabilities and the information is relatively current.
At any rate, here are the links:
http://www.sfu.ca/person/jboyd/lectures/lecture_26.htm
http://www.sfu.ca/person/jboyd/lectures/lecture_27.htm
http://www.sfu.ca/person/jboyd/lectures/lecture_28.htm
And here's the first slide in the lecture (for credit's sake)
http://www.sfu.ca/person/jboyd/lectures/lecture_01.htm
At any rate, here are the links:
http://www.sfu.ca/person/jboyd/lectures/lecture_26.htm
http://www.sfu.ca/person/jboyd/lectures/lecture_27.htm
http://www.sfu.ca/person/jboyd/lectures/lecture_28.htm
And here's the first slide in the lecture (for credit's sake)
http://www.sfu.ca/person/jboyd/lectures/lecture_01.htm