Which type of reins a rider uses, split reins or one rein, is a matter of personal preference. Split reins are commonly seen in the Western riding disciplines, although some Western riders might use one rein. Split reins are heavily preferred by most working cowboys and cowgirls.
Antimicrotubule agent, mitotic inhibitor Oncology An agent that inhibits cancer growth by stopping cell division Pharmacology A drug that inhibits or blocks mitosis in a particular phase of the cell cycleâeg, metaphase arrest caused by colchicine and vinca alkaloids. See Chemotherapy.
Safeguards for Faulty Mitosis. Mitosis is a multi-step process with checkpoints to make sure things are going properly. If a cell detects that something has gone wrong during mitosis, the first thing it does is to stop the process. The three major checkpoints during mitosis -- the G1, G2 and mitotic spindle checkpoints -- all provide the cell with an opportunity to intervene if something goes wrong so that it can fix the problem.