URINARY SYSTEM

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URINARY SYSTEM
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URINARY SYSTEM ORGANS

• KIDNEYS (2)
• URETERS (2)
• URINARY BLADDER
• URETHRA

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KIDNEY FUNCTIONS

• CONTROL BLOOD VOLUME AND COMPOSITION

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KIDNEY FUNCTIONS

• FILTER BLOOD PLASMA, ELIMINATE WASTES
• REGULATE BLOOD VOLUME, PRESSURE
• REGULATE FLUID OSMOLARITY
• SECRETE RENIN
• SECRETE ERYTHROPOIETIN (EPO)
• REGULATE PCO2, ACID-BASE BALANCE
• SYNTHESIZE CALCITROL (VITAMIN D)
• DETOXIFY FREE RADICALS, DRUGS
• GLUCONEOGENESIS

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METABOLIC WASTES

• METABOLISM PRODUCES WASTES
• ESP. CO2, NITROGENOUS WASTES
• RESPIRATORY SYSTEM REMOVES CO2
• URINARY SYSTEM REMOVES BOTH CO2 AND NITROGENOUS
  WASTES

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NITROGENOUS WASTES

• PRODUCTS OF PROTEIN METABOLISM
• PROTEIN ? AMINO ACIDS
• REASSEMBLED INTO PROTEINS
• EXCESS METABOLIZED
• FIRST STEP IS REMOVAL OF AMINO GROUP
• AMMONIA (NH3) IS EXCEEDINGLY TOXIC
• 2NH3 CO2 ?H2NC0NH2 (UREA)
• UREA IS LESS TOXIC THAN AMMONIA
• UREA COMPRISES 50 OF NITROGENOUS WASTES

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NITROGENOUS WASTES

• PRODUCTS OF NUCLEIC ACID METABOLISM
• NUCLEIC ACIDS ? NUCLEOTIDES
• NITROGENOUS BASES REMOVED
• CONVERTED TO URIC ACID
• LESS TOXIC THAN AMMONIA
• LESS ABUNDANT THAN UREA

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NITROGENOUS WASTES

• PRODUCTS OF METABOLISM OF CREATINE PHOSPHATE
• ? CREATININE
• LESS TOXIC THAN AMMONIA
• LESS ABUNDANT THAN UREA

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NITROGENOUS WASTES

• RENAL FAILURE
• ? AZOTEMIA
• ACCUMULATION OF NITROGENOUS WASTES IN BLOOD
• AZOTEMIA ? UREMIA
• MANY NEGATIVE EFFECTS
• E.G., DIARRHEA, VOMITING, ETC.
• ULTIMATELY LETHAL

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EXCRETION

• REMOVAL OF WASTES
• RESPIRATORY SYSTEM
• CO2, WATER
• INTEGUMENTARY SYSTEM
• WATER, SALTS, LACTIC ACID, UREA
• DIGESTIVE SYSTEM
• WATER, SALTS, CO2, LIPIDS, BILE PIGMENTS,
  CHOLESTEROL, ETC.
• URINARY SYSTEM
• METABOLIC WASTES, TOXINS, DRUGS, HORMONES, SALTS,
  H, WATER

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KIDNEY ANATOMY

• PROTECTED BY THREE CONNECTIVE TISSUE LAYERS
• RENAL FASCIA
• ATTACHES TO ABDOMINAL WALL
• ADIPOSE CAPSULE
• FAT CUSHIONING KIDNEY
• RENAL CAPSULE
• FIBROUS SAC
• PROTECTS FROM TRAUMA AND INFECTION

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KIDNEY ANATOMY

• GROSS ANATOMY
• RENAL SINUS
• RENAL PARENCHYMA

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KIDNEY ANATOMY

• RENAL SINUS
• SURROUNDED BY RENAL PARENCHYMA
• CONTAINS BLOOD LYMPH VESSELS, NERVES,
  URINE-COLLECTING STRUCTURES

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KIDNEY ANATOMY

• RENAL PARENCHYMA
• GLANDULAR TISSUE
• FORMS URINE
• TWO ZONES
• OUTER CORTEX
• INNER MEDULLA

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KIDNEY ANATOMY

• RENAL PARENCHYMA
• RENAL PYRAMIDS
• EXTENSIONS OF CORTEX (RENAL COLUMNS) DIVIDE
  MEDULLA INTO 6 10 RENAL PYRAMIDS
• PYRAMID OVERLYING CORTEX LOBE
• POINT OF PYRAMID PAPILLA
• PAPILLA NESTED IN CUP (MINOR CALYX)
• 2 3 MINOR CALICES ? MAJOR CALYX
• 2 3 MAJOR CALICES ? RENAL PELVIS
• RENAL PELVIS ? URETER

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KIDNEY ANATOMY NEPHRONS

• NEPHRONS
• FUNCTIONAL UNITS OF KIDNEY
• 1.2 MILLION PER KIDNEY
• THREE MAIN PARTS
• BLOOD VESSELS
• RENAL CORPUSCLE
• RENAL TUBULE

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NEPHRONS

• BLOOD VESSELS SERVICING KIDNEY
• SUPPLIED BY RENAL ARTERY
• 21 OR CARDIAC OUTPUT
• (MASS IN ONLY 0.4)
• ? ? ?AFFERENT ARTERIOLES
• ? CAPILLARY CLUSTER (GLOMERULUS)

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NEPHRONS

• BLOOD VESSELS SERVICING KIDNEY
• GLOMERULUS
• FENESTRATED CAPILLARIES
• CAPILLARY FILTRATION IN GLOMERULUS INITIATES
  URINE PRODUCTION
• FILTRATE LACKS CELLS PROTEINS
• DRAINED BY EFFERENT ARTERIOLE
• ?PERITUBULAR CAPILLARIES
• ? ? ? ? RENAL VEIN

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NEPHRONS

• RENAL CORPUSCLE
• GLOMERULUS PLUS CAPSULE
• GLOMERULUS ENCLOSED IN TWO-LAYERED GLOMERULAR
  CAPSULE
• BOWMANS CAPSULE
• FLUID FILTERS FROM GLOMERULAR CAPILLARIES
• GLOMERULAR FILTRATE
• FLUID COLLECTS IN CAPSULAR SPACE
• FLUID FLOWS INTO RENAL TUBULE

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NEPHRONS

• RENAL TUBULE
• LEADS FROM GLOMERULAR CAPSULE
• ENDS AT TIP OF MEDULLARY PYRAMID
• 3 CM LONG
• FOUR MAJOR REGIONS
• PROXIMAL CONVOLUTED TUBULE
• NEPHRON LOOP
• DISTAL CONVOLUTED TUBULE
• COLLECTING DUCT

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NEPHRONS

• RENAL TUBULE
• PROXIMAL CONVOLUTED TUBULE (PCT)
• ARISES FROM GLOMERULAR CAPSULE
• LONGEST, MOST COILED REGION
• PROMINENT MICROVILLI
• FUNCTION IN ABSORPTION
• MUCH CONTACT WITH PERITUBULAR CAPILLARIES

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NEPHRONS

• RENAL TUBULE
• NEPHRON LOOP (LOOP OF HENLE)
• U SHAPED, DISTAL TO PCT
• DESCENDING AND ASCENDING LIMBS
• THICK SEGMENTS
• ACTIVE TRANSPORT OF SALTS
• HIGH METABOLISM, MANY MITOCHONDRIA
• THIN SEGMENTS
• PERMEABLE TO WATER
• LOW METABOLISM

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NEPHRONS

• RENAL TUBULE
• DISTAL CONVOLUTED TUBULE (DCT)
• COILED, DISTAL TO NEPHRON LOOP
• SHORTER THAN PCT
• LESS COILED THAN PCT
• VERY FEW MICROVILLI
• CONTACTS AFFERENT AND EFFERENT ARTERIOLES
  (REGULATION IMPARTED)
• CONTACT WITH PERITUBULAR CAPILLARIES

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NEPHRONS

• RENAL TUBULE
• COLLECTING DUCT
• DCTs OF SEVERAL NEPHRONS EMPTY INTO A COLLECTING
  DUCT
• PASSES INTO MEDULLA
• SEVERAL MERGE INTO PAPILLARY DUCT (30 PER
  PAPILLA)
• DRAIN INTO MINOR CALYX

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URINE FORMATION

• OVERVIEW
• BLOOD PLASMA ???? URINE
• FOUR STEPS
• GLOMERULAR FILTRATION
• TUBULAR REABSORPTION
• TUBULAR SECRETION
• WATER CONSERVATION

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URINE FORMATION

• GLOMERULAR FILTRATION MEMBRANE
• CAPILLARY FLUID EXCHANGE
• WATER AND SOME SOLUTES PASS FROM BLOOD INTO
  CAPSULAR SPACE OF NEPHRON
• BARRIERS
• FENESTRATED CAPILLARY ENDOTHELIUM
• PORES EXCLUDE CELLS, ETC.
• BASEMENT MEMBRANE
• OBSTACLE TO ANIONS
• FILTRATION SLITS
• OBSTACLE TO ANIONS

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URINE FORMATION

• GLOMERULAR FILTRATION MEMBRANE
• SMALL MOLECULES PASS THROUGH
• WATER
• ELECTROLYTES
• GLUCOSE
• AMINO ACIDS
• NITROGENOUS WASTES
• VITAMINS
• ETC.
• NORMALLY NOT RBCs, PLASMA PROTEINS

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URINE FORMATION

• GLOMERULAR FILTRATION PRESSURE
• SIMILAR TO CAPILLARY FILTRATION ELSEWHERE
• DIFFERENCES
• BLOOD HYDROSTATIC PRESSURE (BHP) MUCH HIGHER (60
  mmHg)
• AFFERENT ARTERIOLE LARGER THAN EFFERENT
• BHP DROPS VERY LITTLE
• NO REABSORPTION AT VENOUS END

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URINE FORMATION

• GLOMERULAR FILTRATION RATE
• 20 OF FLUID REMOVED FROM BLOOD VIA FILTRATION
• 180 LITERS OF FILTRATE PER DAY
• 60 X PLASMA IN BODY
• 99 REABSORBED

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URINE FORMATION

• TUBULAR REABSORPTION
• GLOMERULAR CAPILLARIES INVOLVED IN FILTRATION
• FILTRATION INTO GLOMERULAR CAPSULE
• PERITUBULAR CAPILLARIES INVOLVED IN REABSORPTION
• REABSORPTION FROM PROXIMAL CONVOLUTED TUBULE, ETC.

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URINE FORMATION

• TUBULAR REABSORPTION
• PERITUBULAR CAPILLARIES
• HIGH OSMOTIC PRESSURE
• RESULT OF WATER LOSS
• LOW HYDROSTATIC PRESSURE
• RESULT OF EFFERENT ARTERIOLE DIAMETER
• CONTACT WITH PROXIMAL CONVOLUTED TUBULE, ETC.
• THESE FACTORS FAVOR REABSORPTION

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URINE FORMATION

• TUBULAR REABSORPTION
• PROXIMAL CONVOLUTED TUBULE
• BLOOD REABSORBS 65 OF FILTRATE
• LONG
• NUMEROUS MICROVILLI
• RETURNS FLUID TO PERITUBULAR CAPILLARIES
• ENERGY-REQUIRING
• NUMEROUS MITOCHONDRIA
• 6 OF RESTING ATP REQUIREMENT

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URINE FORMATION

• TUBULAR REABSORPTION IN PCT
• PCT ? EXTRACELLULAR FLUID ? PERITUBULAR
  CAPILLARIES
• ROUTES OF REABSORPTION
• TRANSCELLULAR
• THROUGH EPITHELIAL CELLS OF PCT
• PARACELLULAR
• BETWEEN EPITHELIAL CELLS OF PCT
• LEAKY TIGHT JUNCTIONS

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URINE FORMATION

• TUBULAR REABSORPTION IN PCT
• WHAT GETS REABSORBED?
• SODIUM, CHLORIDE, OTHER ELECTROLYTES
• GLUCOSE
• AMINO ACIDS
• WATER
• PROTEIN
• NITROGENOUS WASTES
• ETC.

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URINE FORMATION

• TUBULAR REABSORPTION IN PCT
• SODIUM (Na)
• MOST ABUNDANT CATION IN FILTRATE
• TRANSCELLULAR REABSORPTION
• SIMPLE FACILITATED DIFFUSION INTO EPITHELIAL
  CELL (PASSIVE TRANSPORT)
• FROM EPITHELIAL CELL ? ECF (ACTIVE TRANSPORT)
• PERICELLULAR REABSORPTION
• ECF ? PERITUBULAR CAPILLARIES (PASSIVE)
• SODIUM CONCENTRATION GRADIENT DRIVES REABSORPTION
  OF OTHER SUBSTANCES

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URINE FORMATION

• TUBULAR REABSORPTION IN PCT
• GLUCOSE AMINO ACIDS
• TRANSCELLULAR REABSORPTION
• SODIUM-GLUCOSE COTRANSPORT (ACTIVE TRANSPORT)
• SODIUM-AMINO ACID COTRANSPORT (ACTIVE TRANSPORT)
• PASSIVE TRANSPORT FROM EPITHELIAL CELL TO
  EXTRACELLULAR FLUID
• PASSIVE UPTAKE BY PERITUBULAR CAPILLARIES

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URINE FORMATION

• TUBULAR REABSORPTION IN PCT
• WATER
• TUBULAR FLUID HYPOTONIC TO INTRACELLULAR AND
  EXTRACELLULAR FLUIDS
• TRANSCELLULAR REABSORPTION
• PASSIVE TRANSPORT
• PERICELLULAR REABSORPTION
• PASSIVE TRANSPORT
• PASSIVE UPTAKE BY PERITUBULAR CAPILLARIES
• CONSTANT RATE OF WATER REABSORPTION
• MODULATED RATES ELSEWHERE IN NEPHRON

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URINE FORMATION

• TUBULAR REABSORPTION IN PCT
• CHLORIDE (Cl-)
• TRANSCELLULAR AND PARACELLULAR REABSORPTION
• TYPICALLY FOLLOWS SODIUM ION (Na)

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URINE FORMATION

• TUBULAR REABSORPTION IN PCT
• OTHER ELECTROLYTES
• K, Mg, Ca
• PARACELLULAR TRANSCELLULAR REABSORPTION
• SO42-, PO42-, NO3-
• NOT REABSORBED

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URINE FORMATION

• TUBULAR REABSORPTION IN PCT
• PROTEIN
• SMALL AMOUNT IN FILTRATE
• TRANSCELLULAR REABSORPTION
• ENTERS EPITHELIAL CELLS VIA PINOCYTOSIS
  (ENDOCYTOSIS)
• HYDROLYSIS INTO AMINO ACIDS
• PASSIVE TRANSPORT OF AMINO ACIDS INTO
  EXTRACELLULAR FLUID
• PASSIVE UPTAKE BY PERITUBULAR CAPILLARIES

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URINE FORMATION

• TUBULAR REABSORPTION IN PCT
• NITROGENOUS WASTES
• UREA
• PASSIVELY REABSORBED WITH WATER
• 50 OF UREA REABSORBED (INADVERTENTLY)
• URIC ACID
• MOST REABSORBED
• (SECRETED LATER)
• CREATININE
• NOT REABSORBED
• PASSIVE UPTAKE BY PERITUBULAR CAPILLARIES

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URINE FORMATION

• TUBULAR REABSORPTION IN NEPHRON LOOP
• CONCENTRATE URINE, CONSERVE WATER
• REABSORB 20 OF WATER IN FILTRATE
• THIN SEGMENTS
• PASSIVE TRANSPORT
• THICK SEGMENT IMPERMEABLE TO WATER
• REABSORB 25 OF Na, K, Cl-
• COTRANSPORT PROTEINS IN THICK SEGMENTS
• ACTIVE TRANSPORT

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URINE FORMATION

• TUBULAR REABSORPTION IN DCT
• CONCENTRATE URINE, CONSERVE WATER
• 36 LITERS/DAY ENTERS DCT
• REABSORB WATER FROM FILTRATE
• REABSORB SALTS
• SUBJECT TO HORMONAL CONTROL
• ESP. ALDOSTERONE, ANTIDIURETIC HORMONE (ADH),
  ATRIAL NATRIURETIC FACTOR (ANF)
• PCT AND NEPHRON LOOP ARE NOT SUBJECT TO HORMONAL
  CONTROL

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URINE FORMATION

• TUBULAR SECRETION
• CHEMICALS EXTRACTED FROM PERTUBULAR CAPILLARIES
• CAPILLARIES ? RENAL TUBULE
• FUNCTIONS
• WASTE REMOVAL
• ESP. NITROGENOUS WASTES, DRUGS
• ACID-BASE BALANCE
• SECRETION OF H, HCO3-
• REGULATION OF pH OF BODY FLUIDS

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URINE FORMATION

• WATER CONSERVATION
• COLLECTING DUCT
• RECEIVES FROM SEVERAL NEPHRONS
• REABSORBS H20, CONCENTRATES URINE
• BEGINS ISOTONIC TO BLOOD PLASMA
• BECOMES UP TO 4 TIMES MORE CONCENTRATED
• CONCENTRATION OF URINE DEPENDENT UPON BODYS
  STATE OF HYDRATION

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RENAL FUNCTION

• URINALYSIS
• EXAMINATION OF PHYSICAL AND CHEMICAL PROPERTIES
  OF URINE
• CAN DETERMINE PHYSIOLOGICAL STATE OF TISUES
• DIAGNOSTICALLY VALUABLE
• VARIOUS CHARACTERISTICS EVALUATED

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RENAL FUNCTION

• URINALYSIS
• PROPERTIES EVALUATED
• APPEARANCE
• ODOR
• SPECIFIC GRAVITY
• OSMOLARITY
• pH
• CHEMICAL COMPOSITION

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RENAL FUNCTION

• URINE VOLUME
• NORMALLY 1 2 LITERS PER DAY
• gt 2 LITERS / DAY POLYURIA
• CAUSES FLUID INTAKE, DIABETES, DRUGS
• lt 500 ML / DAY OLIGURIA
• CAUSES KIDNEY DISEASE, DEHYDRATION, CIRCULATORY
  SHOCK, PROSTATE ENLARGEMENT, ETC.
• lt 100 ML / DAY ANURIA
• ? AZOTEMIA

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RENAL FUNCTION

• URINE VOLUME
• DIABETES
• 7 TYPES
• CHRONIC POLYURIA
• GENERALLY FROM HIGH GLUCOSE CONCENTRATION IN
  RENAL TUBULE
• GENERALLY RESULTS FROM HIGH GLUCOSE IN BLOOD
• OSMOTIC REABSORPTION OF WATER INHIBITED
• RESULTS IN DEHYDRATION

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RENAL FUNCTION

• URINE VOLUME
• DIURETICS
• CHEMICALS THAT INCREASE URINE VOLUME
• MODE OF ACTION
• INCREASE GLOMERULAR FILTRATION
• E.G., CAFFEINE DILATES AFFERENT ARTERIOLES
• REDUCE TUBULAR REABSORPTION
• E.G., ETHANOL INHIBITS ADH SECRETION
• FUROSEMIDE (LASIX) INHIBITS SODIUM REABSORPTION

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URINE PRODUCTION

• URINE IS PRODUCED CONTINUALLY
• URINE IS ELIMINATED PERIODICALLY
• URINE MUST BE TEMPORARILY STORED

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URINE STORAGE

• URETERS
• CARRY URINE FROM KIDNEYS TO URINARY BLADDER VIA
  PERISTALSIS
• RHYTHMIC CONTRACTION OF SMOOTH MUSCLE
• ENTER BLADDER FROM BELOW
• PRESSURE FROM FULL BLADDER COMPRESSES URETERS AND
  PREVENTS BACKFLOW

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URINE STORAGE

• URETERS
• SMALL DIAMETER
• EASILY OBSTRUCTED OR INJURED BY KIDNEY STONES
  (RENAL CALCULI)

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URINE STORAGE

• URETERS
• KIDNEY STONES
• HARD GRANULE, OFTEN JAGGED
• Ca2, PO42-, URIC ACID, AND PROTEIN
• FORM IN RENAL PELVIS
• USUALLY SMALL, PASS UNDETECTED
• LARGE AND JAGGED CALCULI PAINFUL
• CAUSED BY HYPERCALCEMIA, DEHYDRATION, pH
  IMBALANCES, ETC.
• TREATMENT PASS, SURGERY, ULTRASONICS

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URINE STORAGE

• URINARY BLADDER
• MUSCULAR SAC
• WRINKLES TERMED RUGAE
• OPENINGS OF URETERS COMMON SITE FOR BLADDER
  INFECTION

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URINE ELIMINATION

• URETHRA
• CONVEYS URINE FROM BODY
• INTERNAL URETHRAL SPHINCTER
• RETAINS URINE IN BLADDER
• SMOOTH MUSCLE, INVOLUNTARY
• EXTERNAL URETHRAL SPHINCTER
• PROVIDES VOLUNTARY CONTROL OVER VOIDING OF URINE

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URINE ELIMINATION

• URETHRA
• 3 4 CM LONG IN FEMALES
• BOUND BY CONNECTIVE TISSUE TO ANTERIOR WALL OF
  VAGINA
• URETHRAL ORIFICE EXITS BODY BETWEEN VAGINAL
  ORIFICE AND CLITORIS

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URINE ELIMINATION

• URETHRA
• 18 CM LONG IN MALES
• PROSTATIC URETHRA
• 2.5 CM LONG, URINARY BLADDER ? PROSTATE
• MEMBRANOUS URETHRA
• 0.5 CM, PASSES THROUGH FLOOR OF PELVIC CAVITY
• PENILE URETHRA
• 15 CM LONG, PASSES THROUGH PENIS

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URINE ELIMINATION

• URINATION (MICTURITION)
• 200 ML OF URINE HELD
• DISTENSION INITIATES DESIRE TO VOID
• INTERNAL SPHINCTER RELAXES INVOLUNTARILY
• SMOOTH MUSCLE
• EXTERNAL SPHINCTER VOLUNTARILY RELAXES
• SKELETAL MUSCLE
• POOR CONTROL IN INFANTS
• BLADDER MUSCLE CONTRACTS
• URINE FORCED THROUGH URETHRA

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URINARY DISORDERS

• RENAL INSUFFICIENCY
• EXTENSIVE NEPHRON DESTRUCTION
• KIDNEYS UNABLE TO SUSTAIN HOMEOSTASIS
• ? AZOTEMIA, ACIDOSIS ? UREMIA
• CAUSES
• CHRONIC KIDNEY INFECTIONS
• TRAUMA
• HEAVY METAL OR SOLVENT POISONING
• Hg, Pb, CCl4, ETC.
• RENAL TUBULE BLOCKAGE
• ATHEROSCLEROSIS, REDUCED BLOOD FLOW TO KIDNEY
• GLOMERULONEPHRITIS (AUTOIMMUNE DISEASE)

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URINARY DISORDERS

• RENAL INSUFFICIENCY
• TREATMENT BY HEMODIALYSIS
• WASTES ARTIFICIALLY CLEARED FROM BLOOD
• BLOOD PUMPED FROM RADIAL ARTERY TO A DIALYSIS
  MACHINE
• HEPARIN PREVENTS CLOTTING DURING PROCESS
• WASTES REMOVED BY SIMPLE DIFFUSION
• BLOOD RETURNED THROUGH A VEIN
• TYPICALLY 4 8 HOURS, 3X / WEEK

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