What is a placental cotyledon?
Each of the truncal or main stem villi and their ramifications constitutes a placental lobule or cotyledon. Each lobule is supplied with a single truncal branch of chronic aery. And each lobule has a single vein so that lobules constitute functional units of placental architecture. Ref: Williams 24e pg 94.
All branches from one stem villi
Area supplied by one spiral aery
Quaer of placenta
Area drained by one terminal villi
General obstetrics