mamm. phys - Lab 4 (kidney)

Produced when foods containing protein, such as meat, poultry and certain vegetables are broken down in the body

It is carried in the bloodstream

• Remove liquid waste from the blood in the form of urine
• Keep a stable balance of salts and other substances in the blood
• Produce erythropoietin, a hormone that aids the formation of RBC

remove urea from the blood through filtering units called nephrons

Each nephron consists of a ball formed of small  blood capillaries called a glomerulus  and a small tube called a renal tubule

• Urea + other waste substances = Urine
• Passes through the nephrons and down the renal tubules of the kidney

• Narrow tubes that carry urine down the kidneys to the bladder
• Muscles in ureter walls continually tighten and relax forcing urine downward, away from the kidneys

A kidney infection can develop

Every 10-15 seconds

• Triangle shaped
• Hollow organ located in the lower abdomen
• Held in place by ligaments that are attached to other organs and the pelvic bones
• Bladder walls relax and expand to store urine
• Contract and flatten to empty urine through the urethra

Up to 2 cups of urine for 2 to 5 hours

Circular muscles that help keep the urine from leaking by closing highly like a rubber band around the opening of the bladder

Alert a person when it is time to uriniate, or empty the bladder

• Tube that allows urine to pass outside of the body
• Brain signals bladder muscles to tighten and squeeze urine out of the bladder through the urethra
• Brain signals the sphincter muscles to relax to let urine exit the bladder through the urethra
• When all the signals occur in the correct order, normal urination occurs

• When sodium is reabsorbed by the renal tubules, it is usually accompanied by chloride (to maintain electrostatic neutrality)
• Sodium excreted can be determined by Chloride concetration

• Use 10 drops of urine
• Add 1 drop of 20% Potassium chromate
• Add 2.9% silver nitrate solution, 1 drop at a time 
• Shake after every drop
• Number of drops added = the number of grams of sodium chloride per litre of solution

• Determined by a urinometer
• Fill the urinometer cylinder 3/4 full with urine and place the urinometer float in it
• Ratio between the weight of a given volume of a solution and the weight of the game volume of water
• ↑ Specific gravity of urine = more dissolved solids (urea, sodium, chloride) it contains

• May be obtained by multiplying the final 2 figures of the specific gravity reading by 2.66 (Long's Coefficient)
• This gives a rough estimate of the number of grams of solid per litre of urine
• Ex. if specific gravity is 1.022, it contains about 2.66 x 22 = 58.5 grams of solid per liter

It may be diluted with distilled water

you multiply the decimal portion by the dilution factor

Ex. If diluted urine has a specific gravity of 1.012 and the dilution factor was 2 then the specific gravity of undiluted urine will be 1.024

• About 1.020 (range 1.016 - 1.025)
• Individual urine specimens can vary widely from a s low as 1.001 (after ingesting large amounts of fluid) to as high as 1.040 (when perspiring heavily)

volume for each 60 mins (ml)/60 minutes (min)

Sum of volume of all urine samples except the 1st one / 120 min

total chloride content of all urine samples except the 1st one (g) / total volume in (ml)