Fundamentals of Anatomy and Physiology

The Lymphatic Circulatory System 351

Tonsils

Lymph Circulation

Thymus

Spleen

Peyer’s patches

Small intestine

Lymph nodes

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Figure 15- 1 The vessels and organs of the lymphatic
system.
Lymphatic Vessels
Lymphatic vessels originate as blind-end tubes that begin-
in spaces between cells in most parts of the body. The
tubes, which are closed at one end, occur singly or
in extensive plexuses and are called lymphatic capillaries
(Figures 15-2 and 15-3). These vessels are not found in the
central nervous system, red bone marrow, vascular tissue, or

The Organs of the Lymphatic System.