URINARY SYSTEM
FUNCTIONS
- FLUID HOMEOSTASIS
- REGULATE BLOOD:
- COMPOSITION
- CONCENTRATION
- VOLUME
- pH
- PRESSURE
- MAKES:
- EPO (ERYTHROPOETIN) (HORMONE)
- RENIN (ENZYME)
- EXCRETION OF FLUID WASTE
3 MAJOR PROCESSES THAT TAKE PLACE IN THE KIDNEYS
- FILTRATION
- REABSORPTION
- SECRETION
PATHWAY OF BLOOD THROUGH KIDNEY
RENAL ARTERY>SEGMENTAL ARTERY>INTERLOBAR ARTERY>ARCUATE ARTERY>CORDICAL RADIATE ARTERY>AFFERENT ARTERIOLE>GLOMERULUS> EFFERENT ARTERIOLE>PERTIBULAR CAPILLARIES> VASA RECTA>CORDICAL RADIATE VEIN>ARCUATE VEIN>INTERLOBAR VEIN>RENAL VEIN

NEPHRON ANATOMY
- BOWMANS CAPSULE
- GLOMERULUS
- AFFERENT ARTERIOLE=BLOOD MOVES INTO GLOMERULUS
- EFFERENT ARTERIOLE=BLOOD MOVES OUT
- PROXIMAL CONVOLUTED TUBULE(CLOSEST TO BOWMANS CAPSULE)
- DISTAL CONVOLUTED TUBULE
- LOOP OF HENLE (CONNECTS THESE 2)
- PERITUBULAR CAPILLARIES
- COLLECTING DUCT
- CORTICAL NEPHRON, VEIN, ARTERY, VENULE, VASA RECTA
FILTRATION
- HAPPENS IN THE GLOMERULUS
- MOVEMENT OF FLUID FROM INSIDE THE GLOMERULUS INTO THE BOWMANS CAPSULE
- FILTRATION MEMBRANE: PODOCYTES & FENESTRE
- FILTRATION ONLY WORKS IF
THERE IS A DIFFERENCE IN PRESSURE BETWEEN THE FLUID IN THE
GLOMERULUS & THE FLUID ON THE OTHER SIDE OF THE PODOCYTES
- INCREASE OF PRESSURE IN GLOMERULUS CAUSES FILTRATION TO OCCUR
PODOCYTES
- FILTRATION SLITS, PART OF THE BOWMANS CAPSULE
FENESTRE
- LITTLE HOLES FOUND ON THE GLOMERULUS
- MAKES THEM EXTRA LEAKY
REABSORPTION
- MAIN SITE AT PCT(PROXIMAL CONVOLUTED TUBULE)
- H2O FOLLOWS NA WHEN IT CAN, WHEN ITS ALLOWED, & WHEN CELL MEMBRANE ALLOWS IT
- NA GETS PUMPED VIA ACTIVE TRANSPORT
- CELL MEMBRANES HAVE AQUAPORINS ALLOWING H2O TO FOLLOW NA
COTRANSPORT
- PROTEIN PUMPS OUT CL- AS LONG AS NA IS BEING PUMPED OUT
COUNTERTRANSPORT
- NA/K PUMP
- NA PUMPED OUT, PUMPS K IN THE OPPOSITE DIRECTION
REABSORPTION IN THE PCT
- WHERE THE MAJORITY OF REABSORPTION OCCURS
- 65% NA= REABSORB VIA ACTIVE TRANSPORT
- 65% H2O=REABSORB VIA OSMOSIS (IF PCT IS COMPLETELY PERMEABLE TO WATER)
- 99-100% ORGANIC MOLECULES= REABSORBED BY COTRANSPORT WITH NA
- 60% CL & 90% HCO3= REABSORBED BY ELECTRICAL TRANSPORT WITH NA
- FILTRATE ENTERING PCT IS SIMILAR TO BLOOD PLASMA IT WAS BEFORE
- FILTRATE ENTERING LOOP OF HENLE IS NOT REMOTELY SIMILAR TO THE BLOOD PLASMA IT WAS BEFORE
REABSORPTION IN THE LOOP OF HENLE
- DESCENDING LIMB IS HIGHLY PERMEABLE TO WATER & MODERATELY PERMEABLE TO UREA, NA+, & MANY OTHER IONS
- ASCENDING LIMB IS PERMEABLE TO SOLUTES BUT IMPERMEABLE TO WATER
- NA/CL
IS PUMPED OUT OF ASCENDING LIMB WHICH INCREASES THE CONCENTRATION
WITHIN THE LOOP (THE U)
- THIS CAUSES H2O TO GO OUT OF THE DESCENDING LIMB VIA OSMOSIS BECAUSE IT WANTS TO FOLLOW THE NA
TUBULAR SECRETION
- PCT SECRETIONS:
- H+ VIA COUNTERTRANSPORT W/NA
- K+, SOME DRUGS/TOXINS, URIC ACID, AMMONIUM (NH4)
- DCT SECRETIONS:
- H+ VIA COUNTERTRANSPORT W/NA
- K+
FILTRATION PRESSURE
- GLOMERULAR CAPILLARY PRESSURE
- CAPSULAR HYDROSTATIC PRESSURE
- BLOOD COLLOID OSMOTIC PRESSURE
GLOMERULAR CAPILLARY PRESSURE
- BLOOD PRESSURE INSIDE CAPILLARY TENDS TO MOVE FLUID/SOLUTES OUT OF CAPILLARY INTO BOWMANS CAPSULE
CAPSULAR HYDROSTATIC PRESSURE
- INWARD PRESSURE THAT OPPOSES FILTRATION
- PRESSURE DUE TO THE FORCE OF FILTRATE VOLUME ON THE WALL OF THE BOWMAN CAPSULE
BLOOD COLLOID OSMOTIC PRESSURE
- INWARD PRESSURE/OPPOSES FILTRATION
- DUE TO OSMOTIC PRESSURE OF BLOOD IN GLOMERULUS CAPILLARIES
- PRESENCE OF PROTEINS DRAWS WATER BACK IN TO THE GLOM CAPS FROM BOWMANS AS FLUID TRIES TO LEAVE
ADH (ANTIDIURETIC HORMONE)
- MADE BY: HYPOTHALAMUS, RELEASED BY POSTERIOR PITUITARY GLAND
- TARGET: DISTAL CONVOLUTED TUBE/COLLECTING DUCT
- COMMAND: INCREASE H2O REABSORPTION BY MAKING AQUAPORIN-2
- URINE: VOLUME DECREASES, CONCENTRATION INCREASES
ALDOSTERONE
- MADE BY: ADRENAL GLAND
- TARGET: DCT/CD
- COMMAND: INCREASE SODIUM REABSORPTION, MORE NA FOR ACTIVE TRANSPORT
- URINE: VOLUME: STAYS THE SAME
- URINE: CONCENTRATION: DECREASES. H2O FOLLOWS IF ADH IS PRESENT
ANH (ATRIAL NATRIURETIC HORMONE)
- MADE BY: RIGHT ATRIUM WHEN IT IS OVERSTRETCHED
- TARGET: DCT/CD AND POST PIT.
- COMMAND: DECREASES SODIUM REABSORPTION & ADH RELEASE "DUMP EM BOTH"
- URINE: VOLUME INCREASES, CONCENTRATION STAYS THE SAME
STRUCTURE OF BLADDER
- FUNDUS
- TRIGONE: 3 HOLES, 2 FOR URETERS, 1 FOR URETHRA
- PARIETAL PERITONEUM
URETHRA DIFFERENCES IN MEN & WOMEN
- MEN: 20 CM
- WOMEN: 3 CM
MICTURITION REFELX
3 MUSCLES IN PLAY
- EXTERNAL URETHRAL SPHINCTER(SKELETAL MUSCLE)
- INTERNAL URETHRAL SPHINCTER(SMOOTH MUSCLE)
- DETRUSOR MUSCLE: WALL OF BLADDER: 3 LAYERS: 2 LONGITUDINAL LAYERS WITH A CIRCULAR LAYER IN BETWEEN
- URINE COMES IN (250-300ML), STRETCHES WALL, STARTS REFELX
- DETRUSOR MUSCLE RECEIVES STIMULUS, CONTRACTS
- INTERNAL URETHRAL SPHINCTER: RELAXES
- EXTERNAL URETHRAL SPHINCTER: CONTRACTS UNTIL IT IS TIME TO URINATE
- CAN ACCOMMODATE MORE THAN ONCE
RENAL CALCULI
- KIDNEY STONES
- COMMON CAUSE OF BLOOD IN THE URINE & PAIN IN THE ABDOMEN
- DEVELOPED BY DECREASED URINE VOLUME OR INCREASED EXCRETION OF STONE-FORMING COMPONENTS (CALCIUM, OXALATE, URATE, CYSTINE, XANTHINE, & PHOSPHATE)
DIABETES INSIPIDUS
- DISORDER THAT CAUSES AN IMBALANCE OF WATER IN THE BODY
- LEADS TO INTENSE THIRST EVEN AFTER DRINKING FLUIDS
GLOMERULONEPHRITIS
- INFLAMMATION OF THE GLOMERULI
CHRONIC RENAL FAILURE
- GRADUAL LOSS OF KIDNEY FUNCTION
- CAUSES DANGEROUS LEVELS OF FLUID, ELECTROLYTES, & WASTES BUILD UP IN YOUR BODY
DIURETICS
- SOMETHING THAT PROMOTES THE FORMATION OF URINE BY THE KIDNEY (REDUCE THE AMOUNT OF WATER IN THE BODY)
INCONTINENCE
- LACK OF VOLUNTARY CONTROL OVER URINATION OR DEFACATION
HEMODIALYSIS
- PROCESS BY WHICH WASTE PRODUCTS ARE FILTERED DIRECTLY FROM THE PATIENTS BLOOD
PERITONEAL DIALYSIS
- DIALYSATE PLACED INTO ABDOMINAL CAVITY (PERITONEUM) & DRAINED OUT BY GRAVITY FLOW
- PERITONEAL MEMBRANE ACTS AS FILTER
END STAGE RENAL DISEASE
- LATE STAGES OF CHRONIC RENAL FAILURE WHICH THERE IS IRREVERSIBLE LOSS OF THE FUNCTION OF BOTH KIDNEYS
COUNTER-CURRENT SYSTEM
(EXCHANGE/MULTIPLICATION)
- COUNTERCURRENT EXCHANGE
- TRADE OF SUBSTANCES (NA & CL FOR H2O)
- COUNTERCURRENT MULTIPLICATION
- DEALS WITH CHANGES IN THE CONCENTRATION OF FILTRATE
- AS FILTRATE FALLS DOWN THE DESCENDING LIMB, LOSES H2O=INCREASE IN CONCENTRATION
- AS IT MAKES THE U-TURN INTO THE ASCENDING LIMB, LOSES SOLUTE (NA/CL) BECOMES MORE DILUTED
UREA CYCLING
- COLLECTING DUCT & DESCENDING LIMB PERMEABLE TO UREA
- UREA LEAKS OUT OF CD, ENTERS ISF(INCREASING CONCENTRATION), THEN ENTERS DESCENDING LIMB, ENTERS CD AND REPEATS
- HELPS MAINTAIN OSMOTIC GRADIENT
- WRINGS OUT MORE H2O BY INCREASING CONCENTRATION IN THE ISF
RENIN-ANGIOTENSIN-ALDOSTERONE-ADH SYSTEM
- BP DECREASED (LOWERED KIDNEY PERFUSION)
- JUXTAGLOMERULAR CELL OF KIDNEY RELEASES RENIN
- RENIN CONVERTS ANGIOTENSINOGEN TO ANGIOTENSIN I
- ANGIOTENSIN I CONVERTED TO ANGIOTENSIN II VIA ACE (ANGIO CONVERTING ENZYME)
- ANGIOTENSIN II IS A POWERFUL VASOCONSTRICTOR
- INCREASES ALDOSTERONE RELEASE
- INCREASES ADH RELEASE
- INCREASES BLOOD VOLUME
- INCREASES BLOOD PRESSURE
- INCREASED VESSEL WALL TENSION, BODY RETAINS H2O & NA+
JUXTAGLOMERULAR CELLS
- SMOOTH MUSCLE CELLS AROUND THE AFFERENT ARTERIOLE
- CONTAINS GRAINS
- FILLED WITH RENIN
- MONITORS BLOOD PRESSURE
MACULA DENSA CELLS
- CELLS IN THE DISTAL CONVOLUTED TUBULE
- MONITOR FILTRATE CONCENTRATION