Kidney Function

About 1200mL of blood is filtered thru the kidney each minute!!!!

• Regulate the composition of your 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

AldosteroneRegulated pumpNa+ reclaimed K+ lost

Anti-diuretic (ADH) Hormone controls passive water re- absorption by altering permeability

At this point approximately 1200mL of urine is produced/day and 90% of the water and nutrients that left the blood have been reabsorbed.

FILTRATIONAbout 20% of the fluidbrought to the kidney leaves the blood in the Glomerulus. It must be reabsorbed to prevent dehydration. (180L/day)

                                                                           

             

http://home.comcast.net/~john.kimball1/BiologyPages/K/Kidney.html

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.

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 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 Mechanics

• 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?