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Date of Award

4-25-2003

Document Type

Restricted Thesis: Campus only access

Degree Name

Bachelor of Science

Department

Biology

First Advisor

Dr. Gary P. Radice

Abstract

The lymphatic system is a complex circulatory system that collects fluid from the tissues and interstitial spaces of the body and returns it to the blood. The surplus liquids and salts in the blood are secreted as urine, by way of the kidneys and the urinary bladder. In some species of birds, reptiles and amphibians, the liquid is pumped through the lymphatic system by contractive lymphatic hearts. In Xenopus laevis, these hearts are used to handle the influx of water that can flood the body due to their water-permeable skin and high osmotic potential. During diastole, the posterior lymph hearts receive lymph from the surrounding spaces through numerous afferent pores. Then, during systole, the lymph heart beats lymph out through a single efferent pore into the posterior vertebral vein (Radwanska, 1906, cited in Jones et al., 1997). If the lymph hearts fail, then the lymph remains in the lymphatic vascular system and the lymph accumulates increasingly in the lymph pockets. The liquid eventually presses on the organs and the lung until the suffering animal finally dies. X. laevis tadpoles have two sets of three dorsal lymph hearts on either side of the posterior spine and two anterior lymphatic heart, each located just dorsal to the kidneys on both sides of the animal. X laevis adults, however, only have a single posterior heart, formed from the fusing of the six posterior hearts.

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