hardened (indurated). In the axilla, the inguinal region, and the neck, certain lymph
nodes are large enough to be palpated even in health. Tonsils are aggregates of
c. Lymphocytes. Associated with the lymphatic system are special cells
known as lymphocytes. The lymphocytes become part of the formed elements of the
blood. They are primarily involved in the immune reactions of the body.
10-45. CIRCULATORY SYSTEMS OF LESSER VOLUME
In addition to the cardiovascular and lymphatic circulatory systems, there are
other circulatory systems of lesser volume.
a. The cerebrospinal fluid (CSF) system is involved with the central nervous
system. CSF is formed with fluid from the arteries and eventually returned to venous
b. The bulbus oculi (eyeball) and the inner ear are fluid-filled hollow organs.
Such organs have their own internal circulatory systems. In the case of the bulbus
oculi, the fluid is the aqueous humor. In the case of the inner ear, the fluid is the
endolymph/perilymph. In such cases, the fluids are produced from fluids of arterial
vessels and then are picked up by venous vessels. Should the drainage pattern be
interrupted, fluids will accumulate and cause increased pressure within the hollow
organ. The increased pressure will interfere with the organ functions; examples are
glaucoma of the eye and deafness of the ear.