Gastrointestinal System

If I were to explain the gastrointestinal system it is the system by which ingested food is acted upon by physical and chemical means to provide the body with nutrients it can absorb and to excrete waste products; in mammals the system includes the alimentary canal extending from the mouth to the anus, and the hormones and enzymes assisting in digestion.

Lymphatic System

If I were to explain the lymphatic system it is the vertebrates is a network of conduits that carry a clear fluid called lymph. It also includes the through which the lymph travels. Lymphoid tissue is found in many organs, particularly the lymph nodes, and in the lymphoid follicles associated with the digestive system such as the tonsils. The system also includes all the structures dedicated to the circulation and production of lymphocytes, which includes the spleen, thymus, bone marrow and the lymphoid tissue associated with the digestive system.

Respiratory System

If I were to explain the respiratory system it is the function is to allow oxygen exchange through all parts of the body. The space between the alveoli and the capillaries, the anatomy or structure of the exchange system, and the precise physiological uses of the exchanged gases vary depending on organism. In humans and other mammals, for example, the anatomical features of the respiratory system include airways, lungs, and the respiratory. Molecules of oxygen and carbon dioxide are passively exchanged, by diffusion, between the gaseous external environment and the blood. This exchange process occurs in the alveolar region of the lungs.