B12.2 + B12.3 - Removing Waste Products Flashcards
Why does the waste product carbon dioxide need to be removed?
As dissolved carbon dioxide produces an acidic solution affecting enzymes in cells
How is carbon dioxide removed?
Co2 diffuses from cells into blood and from blood to air in the alveoli then is removed when you exhale
What three substances are removed by the body in urine?
Urea, ions, water
What are two forms of uncontrolled water loss?
Loss of water when exhaling, loss of water through sweat (and mineral ions and urea)
What is selective absorption?
Selective absorption is when useful substances such as glucose, some ions and water are re-absorbed into the blood after filtration by the kidneys
How do the kidneys remove waste products?
Substances are filtered out of the blood as it passes through the kidneys (filtration), the useful ones are selectively re-absorbed
Why is urea produced?
Urea is produced when toxic Ammonia is converted to it in the liver. The urea is then transported to kidneys, filtered and excreted in urine
Why is toxic ammonia found in the body?
Proteins (and the amino acids they’re broken down into) can’t be stored by the body so excess amino acids are converted to carbohydrates and fats in the liver which produces Ammonia too as a waste product
What is the process of converting amino acids to fats and carbohydrates in the liver called?
Deamination
Why is water contained in urine?
The body has to constantly balance water coming in against water being lost (uncontrollably). The amount of water in the body is balanced by the kidneys removing any extra we don’t need and selectively re-absorbing what we do. (consumption also helps balance)
Why is a wrong ion (or water) content bad for the body?
If the balance between ions and water is upset, too much or too little water could be drawn into cells by osmosis, damaging cells or meaning they don’t work as normal
How are ions takin into the body and lost?
Taken in - food
Lost - through sweat (but sweat ion loss is uncontrolled) and kidney filtration + selective absorption (controlled)
How do the kidneys maintain ion balance?
They filter them out of the blood through filtration then selectively reabsorb the right amount back into the blood
Which hormone controls the concentration of urine?
Anti-diuretic hormone (AHD)
What happens if the water content of the body decreases?
If the water content of the body decreases:
1) A receptor in the brain detects that it is too low
2) The coordination centre in the brain receives the information and coordinates a response
3) The pituitary gland releases more ADH so more water is re-absorbed by the kidney tubules
