Chapter 26: Urinary System Flashcards
site of blood filtration and urine production
kidneys
_______ carries urine from kidneys to bladder
ureters
what organ stores urine and squeezes it out during micturition (urination)
bladder
urethra
transports urine during urination
what is urine
filtered blood
3 key functions of the urinary system
excretion of waste production (urea, creatine, uric acid)
elimination as urine
homeostatic regulation of blood
why don’t we “pee dust”?
obligatory water loss, why we still pee when dehydrated
other functions of urinary system?
maintains pH
BP regulation
RBC prod.
Vitamin D. prod.
nephron is…
the functional unit of the kidneys
glomerulus + glomerulus capsule makes…
renal corpuscle
glomerulus (renal corpuscle)
filters 50 gal of filtrate a day into the glomerulus capsule
nephron also…
reabsorbs good that was filtered out (only SMALL things)
secrets waste products
proximal convoluted tubules
part of nephron
reabsorb 70% of water from filtrate
reabsorbs almost 100% of glucose, vitamins, etc
nephron loop
further absorbs water
helps create concentrated urine (juxtamedullary nephron)
distal convoluted tubule
part of nephron
secretes waste products
collecting duct
part of nephron
determines final concentration of urine (under control of ADH)
site of urine production
nephron
what are cortical nephrons?
most numerous (85%)
SHORT nephron loops
responsible for most reabsorption and secretion
what are juxtamedullary nephrons?
15%
more important
responsible for urine concentration
how much blood do kidneys receive a minute
1200 mL
how many gallons of filtrate do kidneys produce a day?
50 gal
flow of urine out of kidneys
renal papilla –> minor calyx –> major calyx –> renal pelvis –> ureter
urters
smooth muscle contractions carry urine to bladder
what has slit-like openings that function like valves>
urters
3 layers of smooth muscle and rugae
bladder
trigone
funnel made by 2 ureteral openings and urethra
internal urethral sphincter
involuntary smooth muscle
external urethral sphincter
voluntary skeletal muscle
micturition
urination
when does the urge to urinate begin?
when bladder has 150 mL of urine
how does voluntarily holding in urine work?
internal sphincter pops open and the skeletal muscle of external sphincter is the ONLY thing keeping you from peeing
proximal urethra
lined with transitional epithelium (to stretch)
distal urethra
lined w/ nonkeratinized stratified squamous epithelium (for protection)
male urethra
1) prostatic urethra (passes thru prostate gland)
2) membrane urethra (passes thru urogenital diaphragm)
3)penile/spongy urethra (travels in corpus spongiosum of the penis)
how long is the male urethra
8 inches
female urethra short length and proximity to anus makes…
UTI’s more common in women
afferent arterioles
feed 1.25 million nephrons per kidneys
where does fluid become filtrate?
in glomerulus where fluid is filtered into it’s capsule where it becomes filtrate
what’s an effective way to remove small waste products from our blood?
filtration
cons of filtration
can’t remove large products
removes small things that we need (glucose, amino acid, acids, vitamins)
what is the filtration membrane made of?
fenestrated membrane
thick basement membrane
special cells (podocytes) w/ feet (pericytes)
renal threshold
excess waste products lost in urine that couldn’t be reabsorbed
GLUCOSE in urine (180-200mg)
loop of henle
nephron loop
ascending nephron loop
reabsorbs sodium
descending nephron loop
permanent aquaporin channels
reabsorption of water
urine travels from
1) nephron
2) collecting duct
3) renal papilla
4) minor calyx
5) major calyx
6) ureter
7) bladder
8) bladder
9) urethra
10) toilet
normal color of urine
pale yellow - deep amber
crystal clear urine
excessive water intake, diabetes
pink/red color in urine
blood
brown color in urine
liver problems
urine odor
should be odorless
old urine smells
pH of urine
changes in urine protects you from deadly pH changes in blood
blood pH may go up when….
exercising
specific gravity of urine
should be higher than 1
WBC in urine
UTIs
protein in urine
high protein diet or intense exercise
leads to protein in blood
ketones in urine
starvation
keto diet
uncontrolled diabetes
nitrides in urine
shouldn’t be in urine
if there, bacterial infection
glucose in urine
shouldn’t be there
if in urine –> blood glucose levels have reaches 180mg/dL or higher
glomerulur filtration rate (GFR)
110 mL/min leads to 50 gal of filtrate per day
net filtration pressure
remains positive in order for kidneys to produce filtrate
drop of _______ in renal BP (10 mmhg) will shut your kidneys off
20%
stages of kidney diseases based on GFR
stage 1: GFR 90+
stage 2: GFR 60-89
stage 3A: GFR 45-59
stage 3B: GFR 30-44
stage 4: GFR 15-29
stage 5: GFR under 15 –> kidney failure
what’s the best way to estimate GFR?
blood creatinine levels
renin angiotensin aldosterone system
raises BP
great target for BP lowering therapies
kidneys are ________ to drops in BP
sensitive
20% drop in renal BP =
GFR is o, kidneys are dead
renin leads to..
production of angiotensin 1
angiotensin 1 goes to _______ where its converted into ___________ by ACE
lungs, angiotensin 2
angiotensin 2
vasoconstriction
stimulate kidneys to reabsorb H2O and sodium
stimulates release of aldosterone
increases ADH
end result of renin angiotensin aldosterone system
BP raised along with blood volume
BP lowering meds are
ACW inhibitors, diuretics, or both
