Download Slide 1

Kidney Function • Regulate the composition of your
About 1200mL of blood
is filtered thru the kidney
each minute!!!!
•
•
•
blood
– keep the concentrations of various ions
and other important substances
constant
– keep the volume of water in your body
constant
– remove wastes from your body (urea,
ammonia, drugs, toxic substances)
– keep the acid/base concentration of
your blood constant
Help regulate your blood pressure
Stimulate the making of red blood cells
Maintain your body's calcium levels
Kidney Functions
Urea from amino acid breakdown, Creatinine from creatine phosphate
breakdown during muscle contraction, uric acid from recycling RNA..
Looking a little closer….
In a normal human
adult, each kidney is
about 12 cm long and
about 5 cm thick,
weighing 150 grams
The Nephron
Aldosterone
Regulated pump
Na+ reclaimed
K+ lost
Anti-diuretic (ADH)
Hormone controls passive
water re- absorption by
altering permeability
FILTRATION
About 20% of
the fluid
brought to the
kidney
leaves the
blood in the
Glomerulus. It
must be
reabsorbed to
prevent
dehydration.
(180L/day)
At this point
approximately
1200mL of urine
is produced/day
and 90% of the
water and
nutrients that left
the blood have
been
reabsorbed.
Rids body of : urea and ammonia from amino acid breakdown, Creatinine from
creatine phosphate breakdown during muscle contraction, uric acid from recycling RNA,
and excess water.
http://home.comcast.net/~john.kimball1/BiologyPages/K/Kidney.html
The Mechanism of Dialysis
• Blood flows by one side of a semipermeable membrane,
and a dialysis solution or fluid flows by the opposite side.
Most smaller solutes can easily pass through the
membrane.
The Unhealthy Kidney
• In the diseased kidney, dialysis is a type of
renal replacement therapy, which is used to
provide an artificial means for lost kidney
function.
• Dialysis can be for acute kidney failure or
permanent kidney failure.
• The semi-permeable membrane used in dialysis
to perform the function of the nephron is the
same as the membrane you are using in your
experiment.
The Mechanics
The concentrations of undesired solutes (among them potassium,
urea, and phosphorus, but including a large number of
compounds about which little is known) are high in the blood, but
low or absent in the dialysis solution.
• www.biotopics.co.uk/human2/andial.html
• The dialysis solution is continually replenished to
maintain the concentration gradient for the removal of
unwanted solutes. The dialysis solution has levels of
minerals like sodium and chloride that are similar to their
natural concentration in healthy blood. For another
solute, bicarbonate, dialysis solution level is set at a
slightly higher level than in healthy blood. This is to
encourage diffusion of bicarbonate from dialysate to the
blood, to neutralize the buildup of acidity acidosis that is
often present in these patients.
• http://www.blobs.org/science/diffusion/imgs/diffusion2.gif
Hemodialysis and peritoneal dialysis
In our experiment….
What happened to the glucose and the starch?
How do you know?