Maintaining Water and Nitrogen Balance Flashcards
Describe how the kidneys produce urine
Blood enters the kidneys through the arteries
The blood passes through the capillaries.in the kidneys
The kidneys filter out and remove glucose, water, ions and urea from the blood into tubules (it doesn’t filter large molecules like protein)
After this all the glucose molecules,and the some of the small water and ion molecules are reabsorbed back into the blood in selective reabsorbtion, the glucose by active transport and the water by osmosis
The urea and excess water and ions are removed from the kidneys as urine.
The urine is stored in the bladder
What is urine made out of?
Urea
Water molecules
Ions
What is selective reabsorbtion?
When glucose and some water and ion molecules are reabsorbed back into the blood after being filtered out by the kidneys- glucose by active transport and water by osmosis
What is deamination?
When the liver breaks down amino acids to produce ammonia
What is a tubule?
A very small tube
Where does deamination take place?
In the liver
Name three ways in which water is lost from our body
Sweat
Exhalation
Urinating
Name two uncontrolled ways in which water is lost from the body
Sweating
Exhalation
What is lost from the body during sweat?
Water
Ions
Urea
What is lost from the body during exhalation?
Water vapour
What is lost from the body durng urination
Water
Ions
Urea
Name a homeostatically controlled way in which water is lost from the body
Urination
Is urea toxic or untoxic?
Toxic
Which part of the body detects changes in water levels in the body?
Hypothalamus
Is blood concentrated or dilute when blood water levels are too low?
Concentrated
Is blood dilute or concentrated when blood water levels are too high?
Dilute
Explain how negative feedback controls blood water levels when blood is dilute
Blood becomes dilute when the body absorbs water from food and drinks
The high blood water levels are detected by the hypothalamus which transmits the information to the coordination centre.
This inhibits the secretion of ADH from the pituitary gland into the blood stream
This decreases the permeability of the kidney tubules to water, decreasing the amount of water which is selectively reabsorbed back into the blood.
This increases the amount of excess water which is released from the kidneys, resulting in a large volume of dilute urine
What molecules are too large to be filtered into the kidney tubules in the production of urine
Proteins
Which molecules are too large to pass through the semi-permeable membrane in kidney dialysis
Protein
Blood cells
A person with kidney failure has _ _ _ _ _ _ concentrations of water, ions and urea in their bloodstream
fill in the blank
A person with kideny failure has higher concentations of water, ions and urea in their bloodstream
Describe the proccess of kidney dialysis
- A person with kidney failure has a high concentration of water, ions and urea in their blood
- This is treated with kidney dialysis. The patient’s blood is seperated from a dialysis fluid by a semi-permeable membrane
- The dialysis fluid contains no urea, so the urea in the person’s blood diffuses from an area of high to low concentration to the dialysis fluid, to remove the urea from the patient’s blood- the dialysis fluid is being constantly refreshed to maintain a large concentration gradient for the urea
- The dialysis fluid also contains normal levels of water and ions, this causes onlysome of the water and ions in the patient’s blood diffuses from an area of high to low concentration to the dialysis fluid.
- This reduces the water and ion levels in the patient’s blood back to normal levels
Name different treatments for kidney failure
Kidney transplant
Kidney dialysis
What happens in a kidney transplant?
A diseased kidney is replaced by a healthy kidney from a donor
Compare the advantanges and disadvantages of kidney dialysis and kidney transplants
Dialysis vs Transplant
No shortageof dialysis machines so they are readily available vs shortage of kidney donors
Expensive for the NHS in the long term vs only expensive in the short term
Patient must misist hospital three times a week and eat a controlled diet to control urea levels in blood from being too high vs Patient can lead a normal life
… vs Risk of rejection by immune system and anti-rejection drugs must be taken everyday, patient may forget to take them, this creates a major health risk
Sh.E.L.D
How does water enter the body?
Water is absorbed from food and drink
How do ions enter the body?
Ions are absorbed from food and drinks
What happens if there is an excess of water (too much water) in the blood
The water travels into the cells by osmosis from an area of high to low concentration along a semi-permeable membrane, when there is too much water in the cells this can cause the cells to burst
What happens if there is too little water in the blood stream?
Water in the cells travels into the blood by osmosis from an area of high to low concentration across a semi-permeable membrane, when the cells lose too much water this can cause them to shrivel
Which molecules are too large to be filtered from the blood into the kidney tubules?
Blood cells
Proteins
What is active transport?
The net movement of molecules from an area of low to high concentration, active transport requires energy
Name two unnatural diuretic substances
Alcohol
Caffiene
How do alcohol and caffiene make someone dehydrated
Alcohol and caffeine are diuretic. This surpresses the secretion of ADH, this means in response, the natural process of less ADH happens unnaturally and the kidney tubules become less permeable to water and so less water is selectively reabsorbed into the bloodstream and there is a high amount of excess water being released from the kidneys as urine so more water is lost- causing dehydration
Alcohol and caffeiene are diuretic.
What is the meaning of diuretic?
Diuretics increase the release of urine from the kidneys by inhibiting the secretion of ADH
Name the risk of not removing excess ions and water in the bloodstream
Death
