Chapter 49.5, Problem 1LO

Summary Introduction

To describe: The actions of secretion, reabsorption, and filtration.

Introduction: Osmoregulation and maintenance of body fluid levels ensure proper thermoregulation, sufficient organ perfusion, electrolyte balance, and excretion of wastes. The exchange of electrolytes and water between the external environment and the animal’s body occurs through specialized epithelial cells. In most vertebrates, the exchange occurs in the kidney by a filtration process. The complex organ kidney consists of numerous repeating units referred to as nephrons. Each nephron has a loop that deeply penetrates the medulla portion of the kidney.