The Kidneys Flashcards
What is osmosis
The movement of water from a dilute to a concentrated solution through a partially permeable membrain
What happens if blood is too dilute
Water moves into cells by osmosis.
What happens if blood is too concentrated
Water moves out of cells by osmosis
Why is it a problem if body cells gain or lose too much water
They don’t work effectively
How does the body gain water
Food and drink
How can the body lose water
Lungs when we exhale- can’t be controlled
Sweat through skin - can’t be controlled
Urine - can be controlled
What does sweat contain
Water, ions , urea
Why can’t the body control sweat
Because it is part of temperature control
What happens if blood is too dilute
The kidneys remove the excess water and the urine has a greater volume
What else is removed in urine
Urea and excess ions
How many kidneys do humans have
2
How do kidneys work
Blood enters through artery ( contains urea) the kidney removes urea and excess ions and water. These leave kidney as urine. Blood leaves kidney through vein. The blood has no urea
Where is urine stored
Bladder
How does kidney work steps
- blood enters via capillaries
- small molecules are filtered out of blood ( urea ions water glucose)
- All of the glucose is reabsorbed some ions and some water are reabsorbed into the blood
- excess are released through urine
What is it called when the kidney only reabsorbs some stuff
Selective reabsorption
Glucose before and after kidney
The same
Ions before and after kidney
Decreased / some reabsored
Urea before and after kidney
Virtually zero
What happens to excess amino acids
The liver breaks down the excess amino acids and produces chemical ammonia
What is the process of converting amino acids into ammonia called
Deamination
What happens to ammonia and why
Ammonia is toxic
So the liver converts it into chemical urea
Which organ converts ammonia into urea
Liver
Two biological reason why kidney transplants are better
Not repeatedly puncturing skin
Less chance of infection
Changes in concentration are minimised
Less chance of damage to body cells
