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FUNCTIONS
MAINTAIN HOMEOSTASIS OF pH, COMPOSITION AND VOLUME OF BODY FLUIDS
REMOVES: METABOLIC WASTE, EXCESS MATERIAL, FOREIGN SUBSTANCES (DRUGS)
KIDNEYS
LOCATED RETROPERITONEALLY 12TH THORACIC TO 3RD LUMBAR
VERTEBRAE RENAL SINUS AT HILUM: BLOOD VESSELS,
URETER, NERVES, LYMPHATIC VESSELS RELEASES ERYTHROPOIETIN ? RELEASES RENIN ?
BLOOD PRESSURE ACTIVATES VITAMIN D ?
CALCIUM ABSORPTION
RENAL PELVIS FUNNEL SHAPED SAC AT URETER ORIGIN WHERE MAJOPR CALYCES MERGE
RENAL MEDULLA: RENAL PYRAMIDS MINOR CALYCES TO MAJOR CALYCES
RENAL CORTEX: OUTER LAYER DIPS IN BETWEEN PYRAMIDS = RENAL
COLUMNSRENAL CAPSULE
FIBROUS CONNECTIVE TISSUEPROTECTION, MAINTAIN SHAPE
BLOOD VESSELS
ARTERIES CAN CARRY 30% OF BLOOD TO KIDNEYS ?
RENAL ARTERY HAS _________________ BLOOD
RENAL VEIN HAS _________________ BLOOD
ARTERIES
Descending aorta Renal artery Interlobar artery Arciform arteries Interlobular arteries Afferent arterioles Glomerulus Efferent arteriole Capillary net
NEPHRON
FUNCTIONAL UNIT OF KIDNEY 1 MILLION PER PARTS
RENAL CORPUSCLE GLOMERULUS GLOMERULAR OR BOWMAN’S CAPSULE
2 LAYERS OF SQUAMOUS EPITHELIAL VISCERAL AND PARIETAL TO TUBULE VISCERAL CELLS: PODOCYTES
HAVE PROCESS AND SECONDARY PROCESSES = PEDICELS, INTERDIGITATE TO FORM SLIT PORES
FUNCTION AFFERENT AND EFFERENT ARTERIOLES
RENAL TUBULE
PROXIMAL CONVOLUTED TUBULE NEPHRON LOOP/ LOOP OF HENLE
DESCENDING LIMB ASCENDING LIMB
DISTAL CONVOLUTED TUBULE COLLECTING DUCT/ COLLECTING TUBULE THROUGH RENAL PAPILAE TO MINOR
CALYX
JUXTAGLOMERULAR APPARATUS
ASCENDING LIMB PASSES BETWEEN AFFERENT AND EFFERENT ARTERIOLE
MACULA DENSA = TALL DENSELY PACKED CELLS OF ASCENDING LOOP TOUCHING ASCENDING LIMB
JUXTAGLOMERULAR CELLS IN WALL OF AFFERENT ARTERIOLE (LARGE VASCULAR SMOOTH MUSCLE CELLS)
REGULATES SECRETION OF RENIN (CHAP 13)
NEPHRONS
CORTICAL 80% CORPUSCLE IN CORTEX CLOSE TO SURFACE SHORT NEPHRON LOOPS
JUXTAMEDULLARY 20% CORPUSCLE CLOSE TO MEDULLA LONG LOOP MOST RESPONSIBLE FOR H2O HOMEOSTASIS
BLOOD SUPPLY OF NEPHRON
AFFERENT ARTERIOLE DIAMETER LARGER THAN EFFERENT ?
PERITUBULAR CAPILLARY SYSTEM VASA RECTA AROUND JUXTAMEDULLARY
NEPHRON LOOP: LOW PRESSURE
URINE FORMATION
WASTES, EXCESS WATER, ELECTROLYTES GLOMERULAR FILTRATION
FILTERS INTO NEPHRON RATHER THAN INTERSTITIAL SPACE
PRODUCES 180 L OF FLUID/DAY SO MOST? TUBULAR REABSORPTION
PICKS UP RIGHT AMOUNT OF WATER, ELECTROLYTES, GLUCOSE
TUBULAR SECRETION REMOVES H+, TOXINS FASTER
URINARY SECRETION = GLOMERULAR FILTRATION + TUBULAR SECRETION – TUBULAR REABSORPTION
GLOMERULAR FILTRATION
MORE PERMEABLE TO SMALL MOLECULES: FENESTRATED CAPILLARIES
= WATER,GLUCOSE, AMINO ACIDS, UREA, URIC ACID, CREATINE, CREATININE, SODIUM, CHLORIDE, POTASSIUM, CALCIUM, BICARBONATE, PHOSPHATE, SULFATE
FILTRATION PRESSURE
HYDROSTATIC PRESSURE CAUSES FILTRATION
ALSO AFFECTED BY HYDROSTATIC PRESSURE IN CAPSULE AND OSMOTIC PRESSURE IN PLASMA ?
NET FILTRATION RATE = GLOMERULAR CAPILLARY HYDROSTATIC PRESSURE – CAPSULAR HYDROSTATIC PRESSURE AND GLOMERULAR CAPILLARY OSMOTIC PRESSURE
NEPHRON RAP
http://www.youtube.com/watch?v=guOqyi5lUQQ
URINARY SYSTEM
http://www.natgeoeducationvideo.com/film/1115/the-urinary-system
DIALYSIS
http://www.youtube.com/watch?v=tQzqGHKkdE8&NR=1&feature=endscreen
FILTRATION RATE
FILTRATION RATE AFFECTED BY ANYTHING THAT AFFECTS GLOMERULAR HYDROSTATIC PRESSURE, GLOMERULAR PLASMA OSMOTIC PRESSURE, OR CAPSULAR HYDROSTATIC PRESSURE
GLOMERULAR HYDROSTATIC PRESSURE IS MOST IMPORTANT: ANY CHANGE IN DIAMETER OF ARTERIOLES, VASODILATION? VASOCONSTRICTION?
MORE FLUID IS FILTERED BECAUSE OF HIGHER HYDROSTATIC PRESSURE SO COLLOIND OSMOTIC PRESSURE DOESN’T AFFECT FILTRATION AS MUCH, UNLESS IT IS LOWERED ?
ANY OBSTRUCTION (?) WOULD BACK UP FLUID RAISING THE HYDROSTATIC PRESSURE OF CAPSULE AND REDUCING FILTRATION
FILTERS: 25% CARDIAC OUTPUT; 20% OF PLASMA = 125 ml/MIN; 180 L/DAY : SO PLASMA IS FILTERED 60X/DAY = 45G
SURFACE AREA OF GLOMERULAR CAPILLARIES = 2 sq m = SKIN’S SURFACE
CONTROL OF FILTRATION RATEGFR
MAINLY AUTOREGULATION BP/VOLUME DROP STIMULATES
SYMPATHETIC NS = VASOCONSTRICTION OF AFFERENT ARTERIOLES = ? IF BP/VOLUME INCREASE = ?
RENIN-ANGIOTENSIN SYSTEM: RENAL BAROMETERS OF AFFERENT ARTERIOLES STIMULATE SYMPATHETIC NS TO STIMULATE JUXTAGLOMERULAR CELLS SECRETE RENIN
DECREASING LEVELS OF SODIUM, POTASSIUM, CHLORIDE STIMULATE MACULA DENSA TO SECRETE RENIN
RENIN STIMULATES ANGIOTENSINOGEN ANGIOTENSIN I; ANGIOTENSIN-CONVERTING ENZYME CAHNGES ANGIOTENSIN I ANGIOTENSIN II
ANGIOTENSIN II: MAINTAINS SODIUM BALANCE, WATER BALANCE, BLOOD PRESSURE
CONSTRICTS AFFERENT OR EFFERENT ARTERIOLES, STIMULATES SECRETION OF ALDOSTERONE FROM ADRENAL CORTEX
ANGIOTENSIN II: VASOCONSTRICTOR OF AFFERENT AND
EFFERENT ARTERIOLES STIMULATE PRODUCTIN OF ALDOSTERONE:
(FROM?) CAUSES RETENTION OF SODIUM IN DISTAL TUBULE: LOSES LESS WATER
STIMULATES RELEASE OF ADH: INCREASES PERMEABILITY OF DISTAL TUBULE AND COLLECTING DUCT
ANP: (FROM?) RELEASED WHEN BLOOD VOLUME INCREASES: SO ?
TUBULAR REABSORPTION
REABSORPTION: MATERIAL TRANSPORTED OUT TO INTER STITIAL FLIUD AND DIFFUSE INTO PERITUBULAR CAPILLARIES
PASSIVE AND ACTIVE MECHANISMS CAUSED BY: LOW HYDROSTATIC
PRESSURE OF PERITUBULAR CAPILLARIES, HIGH PERMEABILITY OF CAPILLARIES, HIGHER COLLOID OSMOTIC PRESSURE OF PERITUBULAR CAPILLRIES
MOSTLY IN PROXIMAL TUBULE, HAVE MICOVILLI (?) GLUCOSE:
PROXIMAL: ACTIVE TRANSPORT UNLESS RENAL PLASMA THRESHOLD IN
REACHED (DIABETES) WATER:
PROXIMAL: OSMOSIS AMINO ACIDS:
PROXIMAL: ACTIVE TRANSPORT SMALL PROTEINS:
PROXIMAL: ACTIVE TRANSPORT: ENDOCYTOSIS CREATINE, LACTIC, CITRIC, URIC AND
ASCORBIC ACID: ACTIVE TRANSPORT
ACTIVE TRANSPORT REQUIRES CARRIER MOLECULES
SODIUM AND WATER RETENTION
WATER: OSMOSIS TIED IN WITH RETENTION OF SODIUM SODIUM PUMP IN PROXIMAL SECTION CHLORIDE, PHOSPHATE AND
BICARBONATE MOVE WITH SODIUM IONS MOST REABSORPTION IN PROXIMAL
TUBULE (70%) MOST SODIUM IS RETAINED (97-99%)
TUBULAR SECRETION
EPITHELIAL CELLS OF TUBULES SECRETE SUBSTANCES ACTIVE TRANSPORT:
ORGANIC COMPOUNDS LIKE PENICILLIN, HISTAMINE
HYDROGEN IONS: WHY? POTASSIUM: WHEN ALDOSTERONE CAUSES
REABSORPTION OF SODIUM = NEGATIVE CHARGE AND POTASSIUM IS SECRETED
REGULATION OF URINE CONTENT
HORMONES: ANP; ALDOSTERONE; ADH ADH FROM ?
POSTERIOR PITUITARY CAUSES DISTAL CONVOLUTED TUBULE AND
COLLECTING DUCTS TO ADD PROTEINS – AQUAORINS: WATER CHANNELS: OSMOSIS BECAUSE OF HYPERTONIC MEDULLA
COUNTERCURRENT EFFECT: ASCENDING LOOP IMPERMEABLE TO WATER BUT LETS ELECTROLYTES OUT SO INSIDE IS HYPOTONIC AND OUTSIDE IS HYPERTONIC
DECENDING LOOP IS PERMEABLE TO WATER NOT SOLUTES, HYPERTONIC OUTSIDE SO WATER DIFFUSES OUT: TUBULAR FLUID IS CONCENTRATED
ASCENDING LOOP REABSORBS MORE SALT, SALT CONCENTRATION KEEPS MULTIPLYING: COUNTERCURRENT MULTIPLIER
MORE THAN 4X SOLUTE CONCENTRATION THAN PLASMA
SALT DIFFUSES INTO DESCENDING VASA RECTA BUT DIFFUSES OUT OF ASCENDING: MAINTAINS SALT GRADIENT IN MEDULLA
UREA AND URIC ACID PRODUCTION
UREA AMINO ACID BREAKDOWN FOR
GLUCONEOGENESIS URIC ACID
METABOLISM OF A AND G 10% EXCRETED/ MOST REABSORBED
URINE COMPOSITION
VARIES ? 95% ?;UREA, URIC ACID, CREATINE,
TRACE AMINO ACIDS, ELECTROLYTES DIET & PHYSICAL ACTIVITY
RENAL CLEARANCE
DEFINITION: KIDNEY’S EFFICIENCY AT REMOVING A SUBSTANCE
TESTED TO SEE IF DISEASE OR DAMAGE INSULIN CLEARANCE TEST: GFR CREATININE CLEARANCE TEST: GFR:
KIDNEY FUNCTION: USUALLY ALL REMOVED FROM BLOOD TO URINE
URETERS 25 cm BEHIND PARIETAL PERITONEUM TO URINARY
BLADDER 3 LAYERS:
MUCOUS COAT: TRANSITIONAL EPITHELIUM MUSCULAR COAT: SMOOTH MUSCLE: CIRCULAR
AND LONGITUDINAL LAYERS FIBROUS COAT: CONNECTIVE TISSUE
MOVES BY PERISTALSIS: STARTED BY PRESENCE OF URINE
VALVE AT URINARY BLADDER ? KIDNEY STONE COULD INCREASE PERISTALSIS OR
SYMPATHETIC NS CONSTRICTS URETER AND KIDNEY SHUTS DOWN
URINARY BLADDER
HOLLOW, BEHIND PARIETAL PERITONEUM TRIGONE: OPENINGS TO URETER AND
URETHRA MUCOUS COAT: TRANSITIONAL
EPITHELIUM SUBMUCOSA: CONNECTIVE TISSUE WITH
GLAND CELLS MUSCULAR COAT: SMOOTH MUSCLE:
DETRUSOR MUSCLE: FORMS INTERNAL URETHRAL SPHINCTER @ NECK
ALWAYS SUSTAINED CONTRACTION PARASYMPATHETIC NS: REFLEX FOR
URINATIONSEROUS COAT: PARIETAL PERITONEUM AT
TOP, FIBROUS CONNECTIVE TISSUE REST
URETHRA
MUCOUS MEMBRANE LONGITUDINAL SMOOTH MUSCLE FIBERS URETHRAL GLANDS: MUCOUS GLANDS MALES: PROSTATIC URETHRA PASSES
THROUGH PROSTATE; MEMBRANOUS URETHRA EXTERNAL URETHRAL SPHINCTER; PENILE URETHRA
MICTURITION
MICTURITION REFLEX: STRETCH RECEPTORS STIMULATED; SIGNAL
MICTURITION REFLEX CENTER: IN SACRAL SPINAL CORD
PARASYMPATHETIC NS IMPULSE TO DETRUSOR MUSCLE TO CONTRACT
CAN STILL BE CONTROLED: EXTERNAL URETHRAL SPHINCTER, IMPULSES FROM BRAIN STEM AND CEREBRAL CORTEX
EXTERNAL URETHRAL SPHINCTER RELAXES: IMPULSES FROM HYPOTHALAMUS AND PONS
DETRUSOR MUSCLE CONTRACTS: MICTURITION IMPULSES STOP; DETRUSOR MUSCLE RELAXES,
BLADDER FILLS
LIFE SPAN CHANGES
KIDNEY CELLS START TO DIE AT 20 BUT NOT NOTICED TILL AFTER 40; 1/3 LOSS BY 80
GLOMERULI SHUT DOWN: LOSS; DAMAGE; GFR DROPS AT 40; 75: 125ml 60ml RENAL TUBULES THICKEN WITH FATTY
ACIDS; DON’T PROCESS DRUGS AND ORGANICE MATERIAL AS WELL
BLOOD FLOW DECREASES BY 50% @ 80
SLOWER TO RESPOND FOR HOMEOSTASIS: ARTERIOLES DON’T DILATE AS QUICK RELEASE OF RENIN DECREASES CAN’T ACTIVATE VITAMIN D
URETER, URINARY BLADDER AND URETHRA AREN’T AS ELASTIC: BLADDER HOLDS 50% LESS AND RETAINS MORE: MORE FREQUENT URINATION AND MORE URGENT
INCONTINENCE: LOSS OF MUSCLE TONE OF BLADDER