A system for separating components defining a cavity for receiving the fluid. The system further includes a rigid insert slidably disposed in the cavity, the insert including a funnel-shaped upper portion and a hole therethrough. The insert has a density such that upon centrifugation a selected component of the fluid resides within the upper portion of the insert. A bone marrow aspiration device includes an introducer needle assembly and an aspiration needle assembly. The introducer needle assembly includes an introducer cannula and a removable trocar. The aspiration needle assembly includes a flexible aspiration cannula and a flexible stylet. The length of the aspiration cannula is substantially greater than the length of the introducer cannula. The aspiration needle assembly is receivable in the introducer cannula when the trocar is removed from the introducer needle assembly. The aspiration cannula forms a channel for aspirating bone marrow when the stylet is removed.
