The internal environment of the body consists of blood, tissue fluid and lymph. In tissues, the liquid component of the blood (plasma) partially seeps through the thin walls of the capillaries, passes into the intercellular spaces and becomes tissue fluid. Excess tissue fluid collects in the lymphatic system and is called lymph. Lymph, in turn, having made a rather difficult path through the lymphatic vessels, enters the bloodstream. Thus the circle closes: blood – tissue fluid – lymph – blood again.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.