4.5.3.3 water and nitrogen balance in the body (SINGLE) Flashcards
What is the kidneys function?
To filter the blood
How do the kidneys produce urine?
They filter waste products out of the blood that flows through the kidneys
Kidneys filter waste products out of the blood that flows through them. What is this stage called?
Filtration
Which substances are absorbed back into the blood after being filtered out during kidney filtration?
Glucose, some ions, water needed by the body.
Substances are absorbed back into the blood after being filtered out during kidney filtration, what is this process called?
Selective reabsorption
What three substances are removed from the body in the urine?
Urea, Ions, Water
What is deamination? Where does it happen?
When proteins and amino acids cannot be stored by the body they are converted into fats and carbohydrate which can be stored. This occurs in the liver
What is the waste product of deamination?
Ammonia
Why is Ammonia converted into urea?
Ammonia is toxic, so the liver converts it into urea
What happens to the urea produced by the liver in the breakdown of excess amino acids and proteins?
Urea is transported to the kidneys in the blood, and filtered out into the urine
How do ions get into the blood?
Taken in with food and drink and absorbed through the walls of the small intestine
Which two ions are in table salt?
sodium and chlorine
Why is maintaining the blood ion concentration important?
If the blood ion concentration changes which will affect the water balance of cells, which can damage cells
If the ion content of the blood is too high what will be the osmotic effect?
Water will leave cells due to osmosis
If the ion content of the blood is too low what will be the osmotic effect?
Water will enter cells due to osmosis
What are the two main ways that ions lost from the body?
Urine and sweat
What are the three methods by which water is lost from the body of organisms?
Urine, sweat, and lungs during exhaling
How is water added to the body?
Food and water, also a product of respiration
Which hormone controls water levels in the body?
ADH
Which gland produces ADH? where is this gland?
Pituitary gland in the brain
Why is ‘water levels in blood’ an example of negative feedback?
A change in water levels brings about a response to restore water levels back to normal
How does the ADH move from the brain to the kidneys?
In the bloodstream
What happens if the brain detects that the level of water in the blood is too high?
The pituitary gland produces less ADH, so less water is reabsorbed from the kidney tubules and more water is removed from the body in the urine
What happens if the brain detects that the level of water in the blood is too low?
The pituitary gland produces more ADH, so more water is reabsorbed from the kidney tubules and less water is removed from the body in the urine
Someone with kidney failure has two options. what are they?
Dialysis or transplant
If the kidneys do not work properly what happens?
Waste substances are not filtered out of the blood, and build up in the body. This can be fatal.
What device does a person suffering from kidney failure have to be connected to several times per week?
Dialysis machine
What does a Dialysis machine to, in simple terms?
Keep dissolved substances at a normal level and remove waste products, just as the kidneys would have done if they worked.
In a dialysis machine what does water and dissolved substances move through?
Partially permeable membrane
By what process does water pass through the partially permeable membrane in the dialysis machine?
Osmosis
By what process do dissolved substances pass through the partially permeable membrane in the dialysis machine?
Diffusion
Which big molecules cannot pass through the partially permeable membrane in a dialysis machine?
Proteins
The dialysis machine fluid has the same concentration of dissolved ions and glucose as what?
Blood
Why does the dialysis machine have the same concentration of glucose and dissolved ions as the blood?
So that ions and glucose are not lost due to diffusion during dialysis treatment
What substances are filtered out of the blood during dialysis?
Urea, excess ions and excess water
How many times per week does a patient with kidney failure need to have dialysis, and how long is each session?
3 times per week, 3-4 hours per session
What are the possible damaging side effects of dialysis treatment?
blood clots and infections
What are the practical drawbacks of dialysis?
It is expensive (for the NHS) and unpleasant
What would be the long term aim of a patient receiving dialysis treatment?
To have a kidney transplanted from a donor
Are kidney transplants a possible cure for kidney failure?
Yes
Are kidney transplants a definite cure for kidney failure? what can go wrong?
- The donated kidney can be rejected by the patients immune system
What is a transplant patient given to reduce the chance of the bodies immune system rejecting the now organ?
Drugs to suppress the immune system
Why is it not possible for all kidney failure patients receive a donated kidney?
There is a long waiting list for donated kidneys, and not enough organs are donated for everyone to have one.
Where do donated kidneys come from?
From a living person who had donated one of their two kidneys, or from someone who has died and carries an organ donor card/is on the organ donor register
