Chapter 7 - Excretion Flashcards
Excretion
The removal from the body of waste products made in the body
Why is excretion necessary?
The body needs to remove waste products before they cause problems
What do the lungs excrete?
Carbon dioxide and water vapor
What do the kidneys excrete?
Water, salts and urea
How is urea made?
When we break down proteins we don’t need
What does the skin excrete?
Water and salts in the form of sweat
What is the function of the urinary system?
To make and excrete urine
What does the urinary system consist of?
The kidneys ( and the blood vessels entering and leaving them), ureters, bladder and urethra
What do the renal arteries do?
○Carry blood into the kidneys
○The blood in the renal arteries contains excess water salts and urea
What do the kidneys do?
○Remove excess water, salts and urea from the blood
○Theses compounds combine to form urine
What do the renal veins do?
○Take blood from the kidneys and carry it back towards the heart
○Blood in the renal veins contains no waste material
What does the bladder do?
○Stores urine until it can be released from the body
What is the urethra?
○A tube which takes urine from the bladder and passes it out of the body
What are the ureters?
○Tubes which carry urine from the kidneys to the bladder
Briefly describe filtration in the kidney
○ Blood enters each kidney through renal arteries
○ In the kidney, waste substances are removed from the blood by filtration
○Main wastes are water salts and urea. The urea and salts dissolve in the water to form urine
○Urine is made in the kidney
○Urine passes from the kidney, through the ureters to the bladder
○Blood that leaves the kidneys in the renal veins does not contain waste products
