The disclosed arterial chambers for hemodialysis may include a cap with a blood inlet port for conveying an intended patient's blood into the arterial chamber, an auxiliary port configured to provide fluid access to the arterial chamber, and a needleless access port configured to couple to a needleless syringe. The needleless access port may be configured for administering a substance to an interior of the arterial chamber from the needleless syringe and/or for withdrawing blood from the interior of the arterial chamber into the needleless syringe. Various tubing sets, hemodialysis systems, and other components, systems, and methods are also disclosed.