1. Respiratory – provides gas exchange in tissues and lungs.
2. Nutrient – delivers nutrients, water and vitamins to tissues and organs.
3. Excretory – removes decay products through the organs of excretion.
4. Thermostatic – maintains a constant body temperature.
5. Regulatory – provides humoral regulation of the body.
6. Protective – contains phagocytes, antibodies
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.