B12.2 Removing waste products Flashcards
What are the 2 main poisonous waste products?
Carbon dioxide and urea
Why does carbon dioxide get produced and what is the problem?
Produced by the body cells during respiration - must be removed because dissolved carbon dioxide produces an acidic solution
How does the body get rid of carbon dioxide?
Diffuses out of the cell by a concentration gradient
Diffuses from the blood into the air in the alveoli of your lungs
Air containing excreted CO2 is released as you exhale
What is the problem of exhaling?
Lose water when the moist air from inside your lungs is forced out the body
What is urea?
Nitrogenous waste produced by the breakdown of excess amino acids in your liver
How is the urea filtered?
Urea passes from the liver cells into your blood - it is dangerous if it builds up
Filtered out of your blood by your kidneys then passed out of the body in the urine produced by the kidneys - along with any excess water and salt
Why is urea produced (higher)?
When you eat more protein than you need or when your tissues are worn out
Extra protein cannot be stored and has to break down - amino acids can’t be used as a fuel directly - liver removes amino acids by a deamination which forms ammonia
Ammonia is converted into urea to be excreted
Rest of the amino acid molecule can then be used in respiration or to make other molecules
What is the ‘no control’ of substances lost to the environment?
Water leaves lungs every time you exhale
Water mineral ions and urea are lost through the skin in sweat
What is the ‘control’ substances that leave the environment?
Urea and excess water and mineral ions removed form the body via the kidney then excreted in the urine
Why are the processes in the kidney regulated?
To maintain the water and mineral ion content of the blood within - narrow limits
An remove urea - poisonous nitrogenous waste
Why is the liver important in the production of urea?
Excess amino acids are carried to the liver in the bloodstream.
The liver removes the amino groups from amino acids by deamination.
This initially forms ammonia, which is converted into urea
Why water - mineral ions and urea are balanced in the body?
If solute concentration outside body cells is higher than cell contents, water will leave cells by osmosis and cells will shrink and stop working.
If solute concentration outside body cells is lower than cell contents,
water will enter cell by osmosis and cells will swell and may burst.
The balance enables body cells to retain shape and work efficiently
Why is it important to be a balance in the body?
It is vital that there is a system by which loss of water and mineral ions can be controlled to maintain a correct osmotic balance between body cells and body fluids and remove poisonous urea, regardless of the body’s water needs.
