1.1细胞生活的环境（The environment in which 1.1 cells live）.docVIP

1.1细胞生活的环境（The environment in which 1.1 cells live） The first chapter is about the internal environment and homeostasis of the human body The first phase of a cell life Content telling I. the living environment of cells in vivo 1. body fluid The body contains a large number of water based liquids, which are collectively referred to as body fluids. Humoral fluids include intracellular fluids (found in cells, about 2/3) and extracellular fluid (approximately 1/3 in cells, including plasma, tissue fluid, lymph, etc.). Life is the direct environment blood plasma; direct in vivo environment most cell life is tissue fluid (i.e. intercellular fluid); a large number of lymphocytes and phagocytic cells is the direct environmental life (lymph or lymph). 2. internal environment Extracellular fluid is the liquid environment that human cells depend on for survival. They are called internal environment, including plasma, tissue fluid, lymph and so on. Sweat, urine, digestive juices, tears and so on, although liquid, but they are only temporary storage in the human body, and direct contact with the outside world, such a liquid does not belong to body fluids, it does not belong to the extracellular fluid. From the conceptual point of view, is the organization of tissue fluid between cells in the interstitial; from the generalized sense, tissue fluid may include lymph and plasma, because the lymph is essentially the mesenchymal cells in lymphoid tissue, and blood plasma is the connective tissue cells in the interstitial tissue, so the extracellular fluid the liquid is about a narrow argument. 3. the relationship between plasma, tissue fluid and lymph The internal connection between the three components of an extracellular fluid is the basis for the complete exchange of cellular and external substances. A capillary wall composed of only one layer of epithelial cells between tissue fluid and plasma. The permeability of capillary wall is high, when blood flows through the capillary, in