1. Outline of stem cell Definition of stem cells、 Morphology and biochemistry characters、Location and types of stem cell、Role of stem cell 2.The basic biological features of stem cell (key point) 1. 1 Definition of stem cells 1.2 Morphology and biochemistry characters of stem cells 1.3 Location and types of stem cell 1.4 Role of stem cell 2.1 Proliferation characters 2. 2 Differentiation characters - multipotency(分化潜能的多向性) 2.3 Microenvironment-dependent(微环境依赖性)