10.1 Overview of the Excretory System Flashcards
What is excretion?
disposal of waste products
What encompasses the excretory system?
kidneys
liver
large intestine
skin
What is the liver responsible for in the excretory system?
excreting many wastes by chemically modifying them and releasing them into bile
What type of waste products does the liver typically handle?
hydrophobic and large waste products
What does the liver synthesize in the excretory system and where does it release it to?
urea; bloodstream
What is urea?
carrier of excess nitrogen resulting from breakdown of proteins
What is the role of the large intestine in the excretory system?
reabsorbs water and ions from feces
What is the role of the skin in the excretory system?
produces sweat that contains water, ions, and urea
What controls sweating?
temperature and level of sympathetic nervous system activity
What is the role of the kidneys in the excretory system?
final responsibility for excretion of hydrophilic wastes
What are the three goals of the homeostatic role of the kidneys in the excretory system?
- excretion of hydrophilic wastes
- maintenance of constant solute concentration and constant pH
- maintenance of constant fluid volume
What are the three main processes that help accomplish the main goals of the homeostatic role of kidneys?
filtration
selective reabsorption
secretion
What is the process of filtration in relation to homeostatic role of kidneys?
passage of pressurized blood over a filter where cells and proteins remain in the blood and water and small molecules enter the renal tubule
What is filtrate?
fluid in the renal tubule that will eventually be made into urine
What is the process of selective reabsorption in relation to homeostatic role of kidneys?
process of taking back useful items (glucose, water, amino acids) while leaving wastes and water in the renal tubule
