13-3 the excretory system web
Post on 27-Apr-2015
92 Views
Preview:
TRANSCRIPT
The Excretory SystemChapter 13 Section 3
The Organs of the Excretory System
The excretory system collects wastes produced by cells and removes the wastes from the body
Excretion- process of removing wastes Urea- chemical that comes from the breakdown of proteins Kidneys- 2 major organs that eliminate urea, excess water,
and some other waste materials Urine- watery fluid produced by kidneys that waste is
eliminated in Ureters- two narrow tubes from which urine flows from the
kidneys to the urinary bladder Urinary bladder- a sacklike muscular organ that stores urine Urethra- small tube from which urine leaves the body
The Excretory System
The Kidney
The Filtering Process
Kidneys act as filtersNephrons- tiny structures that remove
wastes from blood and produce urine
Filtering Out Wastes
Blood flows from the kidneys through arteries to capillaries in a nephron
Capillaries are surrounded by a capsule connected to a long tube
In the capillary cluster, urea, glucose, other chemicals, and some water move out of the blood and into the capsule
Formation of Urine
Urine forms from the filtered material that passes into the capsule
Filtered materials flow through the long, twisting tube
As liquid moves through the tube, many needed substances are reabsorbed into the blood stream
Urea and other wastes remain in the tube
Fluid remaining in the tube is urine
Analyzing Urine for Signs of Disease
Chemical analysis of urine can be useful in detecting some medical problems
Urine normally contains no glucose or protein
Glucose in urine may indicate diabetes
Protein in urine can be a sign of kidneys not functioning properly
Water Balance in the Body
The excretory system helps maintain homeostasis by regulating the amount of water in the body
Your excretory system maintains the amount of water needed in the body by excreting excess fluid and reabsorbing needed fluids
Other Organs of Excretion
Most wastes produced by the body removed through the kidneys
Other organs of excretion are the lungs, skin, and liver
Lungs excrete carbon dioxide and water
Skin excretes wastes through perspiration
The liver breaks down wastes before they are excreted; old RBC hemoglobin recycles to bile
Review
What is the function of the excretory system?
Describe the two stages of urine formation.
What roles do the lungs, skin, and liver play in excretion?
How do the kidneys help regulate the amount of water in the body?
top related