BIOL 1002 Lecture : Notes
Document Summary
11/22/2015 8:41:00 pm: tendency of life to try and maintain the structure and regulate the internal environment, one of the biggest and most frequent homeostatic challenges an animal faces comes from the digestive process. The nephridia in earthworms and mollusks function as simple kidneys: in the earthworm nearly every segment contains a pair of nephridia. Urine with the waste is stored in bladder-like portions of nephridia and excreted through excretory pores in the body wall. The major functions of the excretory system in mammals: excretion of cellular waste products, regulation and maintenance of body fluid composition, ions, water, nutrients, secretion of hormones. These functions occur simultaneously as the kidneys selectively filter the blood: water and nutrients are returned to the blood, wastes (urea), toxins, excessive water and nutrients are collected and eliminated from the body as urine. Excretion in human and other vertebrates is accomplished by the kidneys and the urinary system.
