urinary system indicators of health & disease 3 Flashcards
How is absorbed water returned to the circulatory system?
Via the vasa recta, a looping capillary surrounding the tips of the loops of henle in juxtamedullary nephrons.
what does concentrated urine depend on?
a high solute concentration in interstitial fluid.
In vasa recta (looping capillary), what is the pattern including solutes and water?
as blood descends down the loop, solute goes in and water out, reverse happens when blood is ascending.
what does the loop of henle do?
-sets up a concentration gradient in medulla of kidney,
-concentrates urine. (by reabsorbing water back into the body, which is dependant on interstitial osmolarity gradient.
What do diuretics do in the body?
slow the renal reabsorption of water.
causes diuresis = elevated urine flow rate
what does caffeine inhibit in the body?
It inhibits Na+ reabsorption.
what does alcohol inhibit in the body?
It inhibits ADH secretion.
what are some complications of diuretic use?
dehydration and electrolyte imbalances.
Diuretics can treat what in the body?
hypertension and oedema due to congestive heart failure and cirrhosis of liver.
what are the 3 forms of clinical evaluation of kidney function?
-Urinalysis
-blood screening tests.
-renal plasma clearance
does urine contain protein?
No
What does urinalysis analyse?
volume, chemical and microscopic properties of urine.
how much urine does an adult eliminate every day?
1-2 litres.
what is urine volume influenced by?
Fluid intake, diet, body temp, bp, blood osmolality, mental state and general health.
Name the solutes found in urine.
-urea - from protein breakdown
-creatinine - from creatine phosphate breakdown in muscle
-uric acide - from nucleic acid breakdown
-urobilinogen - from haemoglobin breakdown
Plus FAs, pigments, enzymes and hormones.
Detection of abnormal constituents in urine
Description of colour & appearance
Specific gravity
pH
Glucose
Ketone Bodies
RBC count
WBC count
Protein
Hormone: hCG for pregnancy.
Normal values of urine.
Yellow – amber
Clear
0.75 - 2L/day
pH 7 (4.5 - 8.0)
0.1mg/ml protein
<130mg/day glucose
What can a dipstick measure in urine?
the chemical composition , eg glucose, blood or protein content.
what can blood screening tests find?
-Blood urea nitrogen (BUN) catabolism & deamination of AAs.
-plasma creatinine, catabolism of creatine phosphate in skeletal muscle.
what is renal plasma clearance & what does it measure??
evaluation of kidney function, measures how effective kidneys are at removing a given substance from blood plasma.
how is the renal plasma clearance calculated?
plasma clearance (ml/min) = quantity of urine (ml/min) x concentration in urine (mg/ml) over concentration in plasma (mg/ml)
a high value = efficient excretion of substance in urine.
The volume of plasma per minute needed to excrete the quantity of solute appearing in the urine per minute is known as…
renal plasma clearance.
Describe how normal Renal plasma clearance of glucose is 0
glucose filtered out of blood into renal corpuscle, then reabsorbed into blood. none is secreted out of blood and none is excreted into urine.
explain how normal plasma clearance of creatinine is 120/140ml/min
creatinine is filtered out of blood to renal corpuscle, all is excreted into urine.
none reabsorbed into blood.
how much urine can bladder hold?
700-800ml
what is micturition?
a process where urine is expelled from the body.
when bladder is over 200-400ml full, stretch receptors transmit nerve impulses to spinal cord s2 and s3 triggering micturition relfex.
explain what polycystic kidney disease looks like.
multiple cysts, can be genetic, reduces kidney functions - high BP, liver cysts, kidney failure, blood vessel problems.
describe diabetic nephropathy
occurs with chronic diabetes after 10-15 years onset, affects ages 50-70
Albuminuria detected.
usually smaller in size.
describe pathophysiology.
Thickened glomerulus, abnormal blood vessels, increasing number of glomeruli destroyed.
Name the 4 types of UTIs
Urethritis, cystitis (bladder), pyelitis (walls of renal pelvis near hilus), pyelonephritis (if also inflame renal cortex and medulla).
If uti is chronic, and affects kindly, scar tissue forms in kidney severely impairing the function.
what is dialysis?
where blood is removed, cleaned artificially through selectively permeable membrane and brought back into the body.
is dialysis fluid composition similar to blood?
Yes, accept it has little waste.
What are kidney stone known as?
Renal calculi.
describe renal calculi (kidney stones)
crystal aggregations of dissolved minerals in urine, size can vary from grain of sand to a grapefruit. If 2-3mm, can obstruct ureter, causes renal colic (pain).
Why do kidney stones ( renal calculi) form?
excessive calcium, scant water intake, abnormal alkaline or acidic urine. overactive parathyroid gland.
how can kidney stones be broke down?
shock waves
