Science Focus 4.4 Flashcards
A build-up of any waste in the body can be harmful. ________ is the removal of waste from the body
Excretion
What is Excretion?
The removal of waste from the body.
A waste product that is harmful if allowed to build up is ____, produced by the liver after protein has been digested.
urea
Urea passes into the bloodstream where it travels to the _______ to be filtered out with excess water and other waste products in the blood.
kidneys
Kidneys are red-brown, bean-shaped organs about the size of a fist, which filter an amazing ___ litres of blood every minute.
1.3
Each kidney contains over a million tiny filtration units called ________.
nephrons
About one millilitre of blood per litre is filtered out as waste liquid, or _____.
urine
Urine is produced at the rate of a drop per minute, or ____ litres per day.
one to two
Urine consists of about 95 per cent _____ and 5 per cent ____, as well as small amounts of salts and other substances such as bile, which gives urine its yellow colour.
water; urea
Sometimes concentrated substances in urine may crystallise into small, solid particles called ____ ____ within the kidneys, ureters or bladder.
kidney stones
Kidney stones can cause extreme ____.
pain
Often kidney stones will pass out of the body, though in some cases surgical procedures, based on the properties of sound, are used. They are:
ultrasound; Extracorporeal Shock-Wave Lithotripsy (ESWL)
One way to reduce the risk of kidney stones is to:
drink at least a litre of water every day.
Can we lose the function of a single kidney and still continue a normal life with one healthy kidney?
Yes
If both kidneys fail, the situation is life-threatening due to the build up of poisonous wastes in the blood. What are the treatment options?
a kidney transplant or dialysis.
