Hole's人体解剖生理学 48.docx - docrine glands to their target...

docrine glands to their target tissues, and carries wastes
from body cells to the excretory organs, where the wastes
are removed from the blood and released to the outside.
Blood and the cardiovascular system are discussed in
chapters 14 and 15.
The lymphatic system (fig. 1.14) is sometimes con -
sidered part of the cardiovascular system. It is also in -
volved with transport and is composed of the lymphatic
vessels, lymph fluid, lymph nodes, thymus gland, and
spleen. This system transports some of the fluid from the
spaces within tissues (tissue fluid) back to the blood stream
and carries certain fatty substances away from the
digestive organs. Cells of the lymphatic system are called
lymphocytes, and they defend the body against infec tions
by removing disease-causing microorganisms and viruses
from the tissue fluid. The lymphatic system is discussed in
chapter 16.
Absorption and Excretion
Organs in several systems absorb nutrients and oxygen
and excrete wastes. The organs of the digestive system