A system closable to the atmosphere for obtaining an enriched mesenchymal stem cell and/or hematopoietic stem cell portion from a cell suspension, or for obtaining an enriched bone marrow aspirate concentrate fraction from bone marrow, the system comprising: a. a collection tube for collecting the cell suspension or the bone marrow aspirate; b. a first collection syringe for collecting a poor cellular fluid portion; c. a second collection syringe for collecting an enriched mesenchymal stem cell and/or hematopoietic stem cell portion or for collecting enriched bone marrow cells, wherein said second collection syringe comprises a filter unit having an effective pore size of about 3-50μm; and d. at least one needle for attaching to each said syringe; wherein said collection tube comprises at least one stopper; an anticoagulant portion; and a portion of separation gel, said gel having a density of about 1.04 - 1.09 gr/cm 3, and wherein said collection tube is adapted such that, when containing said cell suspension or said bone marrow aspirate, yields the following separation fractions after centrifugation: a first fraction comprising primarily red blood cells (RBCs), a second fraction comprising a gel layer, a third fraction comprising a cellular fraction containing enriched MSC and/or HSC or enriched bone marrow nucleated cells on top of said gel layer, and a fourth fraction comprising poor cellular fluid. a. a collection tube for collecting the cell suspension or the bone marrow aspirate; b. a first collection syringe for collecting a poor cellular fluid portion; c. a second collection syringe for collecting an enriched mesenchymal stem cell and/or hematopoietic stem cell portion or for collecting enriched bone marrow cells, wherein said second collection syringe comprises a filter unit having an effective pore size of about 3-50μm; and d. at least one needle for attaching to each said syringe; wherein said collection tube comprises at least one stopper; an anticoagulant portion; and a portion of separation gel, said gel having a density of about 1.04 - 1.09 gr/cm 3, and wherein said collection tube is adapted such that, when containing said cell suspension or said bone marrow aspirate, yields the following separation fractions after centrifugation: a first fraction comprising primarily red blood cells (RBCs), a second fraction comprising a gel layer, a third fraction comprising a cellular fraction containing enriched MSC and/or HSC or enriched bone marrow nucleated cells on top of said gel layer, and a fourth fraction comprising poor cellular fluid. wherein said collection tube comprises at least one stopper; an anticoagulant portion; and a portion of separation gel, said gel having a density of about 1.04 - 1.09 gr/cm 3, and at least one stopper; an anticoagulant portion; and a portion of separation gel, said gel having a density of about 1.04 - 1.09 gr/cm 3, and wherein said collection tube is adapted such that, when containing said cell suspension or said bone marrow aspirate, yields the following separation fractions after centrifugation: a first fraction comprising primarily red blood cells (RBCs), a second fraction comprising a gel layer, a third fraction comprising a cellular fraction containing enriched MSC and/or HSC or enriched bone marrow nucleated cells on top of said gel layer, and a fourth fraction comprising poor cellular fluid. a first fraction comprising primarily red blood cells (RBCs), a second fraction comprising a gel layer, a third fraction comprising a cellular fraction containing enriched MSC and/or HSC or enriched bone marrow nucleated cells on top of said gel layer, and a fourth fraction comprising poor cellular fluid.