Balance{ Water}
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Balance{ Water} Balance{ Water} Presentation Transcript

  • BALANCE WATER ACID-BASE ELECTROLYTE
  • WATER BALANCE
    • NORMAL WATER CONTENT OF BODY
    • 75% AT BIRTH
    • 55-60% YOUNG ADULTS
      • MEN SLIGHTLY HIGHER THAN WOMEN
      • (MORE FAT, LESS WATER)
    • 45% IN ELDERLY, OBESE
  • WATER BALANCE
    • TOTAL BODY WATER
    • ~40 LITERS
    • SEVERAL FLUID COMPARTMENTS
      • 65% INTRACELLULAR FLUID (ICF)
      • 35% EXTRACELLULAR FLUID (ECF)
        • 25% INTERSTITIAL FLUID (TISSUE FLUID)
        • 8% BLOOD PLASMA AND LYMPH
        • 2% TRANSCELLULAR FLUID
          • SYNOVIAL, PLEURAL, PERICARDIAL, ETC.
  • WATER BALANCE
    • TOTAL BODY WATER
    • ENTERS BODY
      • OSMOSIS FROM DIGESTIVE TRACT
        • ALSO PRODUCED BY AEROBIC RESPIRATION
        • ALSO PRODUCED BY CONDENSATION REACTIONS
    • EXITS BODY
      • URINARY, DIGESTIVE, RESPIRATORY, & INTEGUMENTARY SYSTEMS
  • WATER BALANCE
    • TOTAL BODY WATER
    • FLUID EXCHANGED BETWEEN COMPARTMENTS
      • CAPILLARY WALLS, PLASMA MEMBRANES
      • DRIVEN BY TRANSIENT OSMOTIC GRADIENTS
      • OSMOTIC GRADIENTS DEPENDENT ON SOLUTE MOLECULES
      • MOST ABUNDANT SOLUTES ARE ELECTROLYTES
      • WATER BALANCE AND ELECTROLYTE BALANCE ARE CLOSELY RELATED
  •  
  • WATER BALANCE
    • WATER BALANCE
    • FLUID GAIN = FLUID LOSS
    • BOTH TYPICALLY ~2500 ML / DAY
  • WATER BALANCE
    • WATER GAIN
    • TYPICALLY ~2500 ML / DAY
    • 1600 ML FROM DRINK
    • 700 ML FROM FOOD
    • 200 ML FROM METABOLISM
      • AEROBIC RESPIRATION
      • CONDENSATION REACTIONS
        • A.K.A. DEHYDRATION REACTIONS
  • WATER BALANCE
    • WATER LOSS
    • TYPICALLY ~2500 ML / DAY
    • 1500 ML EXCRETED AS URINE
    • 200 ML ELIMINATED IN FECES
    • 300 ML EXPIRED IN BREATH
    • 100 ML SECRETED AS SWEAT
    • 400 ML LOST AS CUTANEOUS TRANSPIRATION
      • DIFFUSES THROUGH EPIDERMIS, EVAPORATES
  •  
  •  
  • WATER BALANCE
    • WATER LOSS
    • CAN VARY GREATLY
      • INCREASED RESPIRATORY LOSS IN COLD WEATHER
      • INCREASED SWEAT LOSS IN WARM WEATHER
      • INCREASED RESPIRATORY AND SWEAT LOSS, DECREASED URINE OUTPUT DURING PHYSICAL EXERTION
  • WATER BALANCE
    • WATER LOSS
    • OBLIGATORY WATER LOSS
      • RELATIVELY UNAVOIDABLE
      • EXPIRED AIR, CUTANEOUS TRANSPIRATION, SWEAT, FECAL MOISTURE, MINIMUM URINE OUTPUT (~400 ML/DAY)
  • WATER BALANCE
    • REGULATION OF WATER INTAKE
    • GOVERNED BY THIRST
      • PROVOKED BY INCREASED PLASMA OSMOLARITY
      • PROVOKED BY BLOOD LOSS
    • THIRST CENTER IN HYPOTHALAMUS
      • RESPONDS TO SIGNS OF DEHYDRATION
        • ANGIOTENSIN II
        • ANTIDIURETIC HORMONE (ADH)
        • SIGNALS FROM OSMOCENTERS
      • INHIBITS SALIVATION
  • WATER BALANCE
    • REGULATION OF WATER INTAKE
    • INHIBITED SALIVATION
      • DRY MOUTH
      • SENSE OF THIRST
      • INGESTION OF WATER
        • COOLS AND MOISTENS MOUTH
        • DISTENDS STOMACH AND INTESTINES
        • REHYDRATES BLOOD
      • THIRST INHIBITED
  •  
  • WATER BALANCE
    • REGULATION OF WATER OUTPUT
    • CONTROLLED VIA ALTERATIONS IN URINE VOLUME
    • URINE VOLUME AFFECTED BY
      • SODIUM REABSORPTION
        • WATER FOLLOWS SODIUM REABSORPTION
        • MORE LATER
      • ANTIDIURETIC HORMONE (ADH)
        • BLOOD VOLUME  , [Na+]  , OSMORECEPTORS STIMULATED, PITUITARY RELEASES ADH
        • AQUAPORINS PRODUCED IN KIDNEY’S COLLECTING DUCTS
        • FACILITATE REABSORPTION
        • ALSO WORKS IN REVERSE
  •  
  • WATER BALANCE
    • WATER BALANCE DISORDERS
    • FLUID DEFICIENCY
      • VOLUME DEPLETION (HYOVOLEMIA)
      • DEHYDRATION
    • FLUID EXCESS
      • VOLUME EXCESS
      • HYPOTONIC HYDRATION
    • FLUID SEQUESTRATION
  • WATER BALANCE
    • WATER BALANCE DISORDERS
    • FLUID DEFICIENCY: HYPOVOLEMIA
    • CAUSED BY PROPORTIONATE LOSS OF WATER AND SODIUM WITHOUT REPLACEMENT
    • TOTAL BODY WATER DECREASED
    • OSMOLARITY UNCHANGED
    • CAUSES
      • HEMORRHAGE
      • SEVERE BURNS
      • CHRONIC VOMITING OR DIARRHEA
        • MAJOR CAUSE OF INFANT MORTALITY
  • WATER BALANCE
    • WATER BALANCE DISORDERS
    • FLUID DEFICIENCY: DEHYDRATION
    • CAUSED BY LOSS OF MORE WATER THAN Na +
    • TOTAL BODY WATER DECREASED
    • ECF OSMOLARITY INCREASES
    • CAUSES
      • LACK OF DRINKING WATER
      • DIABETES MELLITUS
      • ADH HYPOSECRETION
      • PROFUSE SWEATING
      • OVERUSE OF DIURETICS
  • WATER BALANCE
    • WATER BALANCE DISORDERS
    • FLUID DEFICIENCY: DEHYDRATION
    • AFFECTS ALL FLUID COMPARTMENTS
    • INFANTS MORE VULNERABLE THAN ADULTS
      • HIGHER METABOLISM  MORE WASTES
        • MORE WASTES  MORE URINE VOLUME
      • IMMATURE KIDNEYS
        • URINE LESS CONCENTRATED
      • GREATER SURFACE AREA-TO-VOLUME RATIO
        • GREATER WATER LOSS BY EVAPORATION
  • WATER BALANCE
    • WATER BALANCE DISORDERS
    • EFFECTS OF FLUID DEFICIENCY
    • CIRCULATORY SHOCK
      • DUE TO LOSS OF BLOOD VOLUME
    • NEUROLOGICAL DYSFUNCTION
      • DUE TO DEHYDRATION OF BRAIN CELLS
  • WATER BALANCE
    • WATER BALANCE DISORDERS
    • FLUID EXCESS
    • LESS COMMON THAN FLUID DEFICIENCY
      • KIDNEYS ARE TYPICALLY ABLE TO EXCRETE MORE URINE
  • WATER BALANCE
    • WATER BALANCE DISORDERS
    • FLUID EXCESS: VOLUME EXCESS
    • CAUSED BY PROPORTIONATE RETENTION OF EXCESS WATER AND SODIUM
    • TOTAL BODY WATER INCREASED
    • OSMOLARITY UNCHANGED
    • CAUSES
      • ALDOSTERONE HYPERSECRETION
      • RENAL FAILURE
  • WATER BALANCE
    • WATER BALANCE DISORDERS
    • FLUID EXCESS: HYPOTONIC HYDRATION
    • “ WATER INTOXICATION”, “POS H 2 0 BALANCE”
    • CAUSED BY RETENTION OF MORE WATER THAN SODIUM
    • TOTAL BODY WATER INCREASED
    • ECF OSMOLARITY DECREASES
    • CAUSES
      • REPLACEMENT OF WATER AND SALT WITH WATER
        • LACK OF PROPORTIONATE INTAKE OF ELECTROLYTES
      • ADH HYERSECRETION
  • WATER BALANCE
    • WATER BALANCE DISORDERS
    • EFFECTS OF FLUID EXCESS
    • PULMONARY EDEMA
    • CEREBRAL EDEMA
  • WATER BALANCE
    • WATER BALANCE DISORDERS
    • FLUID SEQUESTRATION
    • EXCESS FLUID ACCUMULATES IN A PARTICULAR LOCATION
    • TOTAL BODY WATER MAY BE NORMAL
    • CIRCULATING VOLUME MAY DROP
    • EXAMPLES
      • EDEMA (IN INTERSTITIAL SPACES)
      • HEMORRHAGE (LOST TO CIRCULATION)
      • PLEURAL EFFUSION (IN PLEURAL CAVITY)
  • ELECTROLYTE BALANCE
    • IMPORTANCE OF ELECTROLYTES
    • SALTS
      • E.G. NaCl, Ca 3 (PO 4 ) 2 , ETC.
      • INCLUDE IONS IN DEFINITION
    • MANY ROLES
      • INVOLVED IN METABOLISM
      • DETERMINE ELECTRICAL MEMBRANE POTENTIALS
      • AFFECT OSMOLARITY OF BODY FLUIDS
      • AFFECT WATER CONTENT AND DISTRIBUTION
      • ETC.
  • ELECTROLYTE BALANCE
    • SODIUM
    • PRINCIPAL EXTRACELLULAR CATION
      • 90 – 95% OF OSMOLARITY FROM SODIUM SALTS
    • ROLES
      • DEPOLARIZATION
        • MUSCLES, NERVES
      • AFFECT TOTAL BODY WATER
      • AFFECT WATER DISTRIBUTION
      • COTRANSPORT
        • GLUCOSE, AMINO ACIDS, CALCIUM, ETC.
      • ETC.
  • ELECTROLYTE BALANCE
    • SODIUM HOMEOSTASIS
    • 0.5 G / DAY DIETARY REQUIREMENT
    • RECEIVE 3 – 7 G / DAY FROM OUR DIET
    • KIDNEYS EXCRETE EXCESS (~5 G / DAY)
    • EXCRETION REGULATED BY 3 HORMONES
      • ALDOSTERONE
      • ANTIDIURETIC HORMONE (ADH)
      • ATRIAL NATRIURETIC FACTOR (ANF)
  • ELECTROLYTE BALANCE
    • SODIUM HOMEOSTASIS
    • REGULATION BY ALDOSTERONE
    • “SALT-RETAINING HORMONE”
    • STEROID HORMONE
    • ALDOSTERONE SECRETION STIMULATED BY:
      • HYPONATREMIA
      • HYPERKALEMIA
      • HYPOTENSION
  • ELECTROLYTE BALANCE
    • SODIUM HOMEOSTASIS
    • REGULATION BY ALDOSTERONE
    • TARGET CELLS
      • DISTAL CONVOLUTED TUBULE
      • COLLECTING DUCT
    • TRANSCRIBE GENE FOR Na + -K + PUMP
      • SODIUM REABSORPTION INCREASES
      • H + AND K + SECRETION INCREASES
      • URINE pH DROPS
  • ELECTROLYTE BALANCE
    • SODIUM HOMEOSTASIS
    • REGULATION BY ALDOSTERONE
    • AVERAGE Na + EXCRETION 5 G / DAY
    • ALDOSTERONE REDUCES TO ~0
    • WATER REABSRBED PROPORTIONALLY
    • SODIUM CONCENTRATION IN BODY UNCHANGED
  • ELECTROLYTE BALANCE
    • SODIUM HOMEOSTASIS
    • REGULATION BY ALDOSTERONE
    • INHIBITED BY HYPERTENSION
    • KIDNEYS THEN REABSORB LITTLE Na +
    • EXCRETION INCREASED TO ~30 G / DAY
  •  
  • ELECTROLYTE BALANCE
    • SODIUM HOMEOSTASIS
    • REGULATION BY ADH
    • INDEPENDENTLY MODIFIES SODIUM AND WATER EXCRETION
      • CAN CHANGE SODIUM CONCENTRATION
    • HIGH BLOOD [Na + ]  ADH SECRETION
      • INCREASES WATER REABSORPTION
        • SODIUM CONCENTRATION DECREASED
      • ADH ALSO STIMULATES THIRST
    • ALSO HAPPENS IN REVERSE
  • ELECTROLYTE BALANCE
    • SODIUM HOMEOSTASIS
    • REGULATION BY ANF
    • HYPERTENSION  ANF SECRETION
      • INHIBITS ADH AND RENIN SECRETION
      • INHIBITS SODIUM & WATER REABSORPTION
      • MORE SODIUM AND WATER EXCRETED
      • BLOOD PRESSURE DECREASED
  • ELECTROLYTE BALANCE
    • SODIUM HOMEOSTASIS
    • REGULATION BY OTHER HORMONES
    • ESTROGENS MIMIC ALDOSTERONE
      • WATER RETENTION DURING PREGNANCY
      • MENSTRUAL WATER RETENTION
    • PROGESTERONE
      • REDUCES SODIUM REABSORPTION
      • DIURETIC AEFFECT
    • GLUCOCORTICOIDS
      • PROMOTE SODIUM REABSORPTION, EDEMA
  • ELECTROLYTE BALANCE
    • SODIUM HOMEOSTASIS: IMBALANCES
    • RELATIVELY RARE
    • HYPERNATREMIA
      • CAN RESULT FROM IV SALINE
      • CAUSES WATER RETENTION, HYPERTENSION, EDEMA
    • HYPONATREMIA
      • GENERALLY FROM WATER EXCESS
      • HYPOTONIC HYDRATION
      • CORRECTED BY EXCRETION OF EXCESS WATER
  • ELECTROLYTE BALANCE
    • POTASSIUM
    • PRINCIPAL INTRACELLULAR CATION
    • AFFECTS INTRACELLULAR OSMOLARITY
    • AFFECTS CELL VOLUME
    • ROLES
      • PRODUCES RESTING & ACTION POTENTIALS
      • COTRANSPORT
      • THERMOGENESIS
      • COFACTOR FOR PROTEIN SYNTHESIS
  • ELECTROLYTE BALANCE
    • POTASSIUM HOMEOSTASIS
    • HOMEOSTASIS LINKED TO THAT OF Na +
      • K + AND Na + COREGULATED BY ALDOSTERONE
    • 90% OF K + REABSORBED IN PCT
      • REMAINDER EXCRETED IN URINE
    • CONTROL IMPARTED IN DCT & COLLECTING DUCT (CD)
      • HIGH [K + ]  SECRETE MORE INTO FILTRATE
      • LOW [K + ]  SECRETE LESS INTO FILTRATE
      • EXCHANGED FOR Na +
  • ELECTROLYTE BALANCE
    • POTASSIUM HOMEOSTASIS
    • REGULATION BY ALDOSTERONE
    • HIGH [K + ]  ALDOSTERONE PRODUCTION
      • Na + -K + PUMP PRODUCED
      • Na + AND K + COREGULATED
      • INCREASE K + SECRETION
      • DECREASE Na + SECRETION
  • ELECTROLYTE BALANCE
    • POTASSIUM HOMEOSTASIS: IMBALANCES
    • MOST DANGEROUS ELECTROLYTE IMBALANCES
    • HYPERKALEMIA
      • EFFECTS DEPEND ON SPEED OF CONC RISE
      • QUICK RISE  NERVE/MUSCLE CELLS VERY EXCITABLE
      •  CARDIAC ARREST
        • E.G., K+ RELEASED FROM INJURED CELLS
        • E.G., TRANSFUSION WITH OLD BLOOD
        • E.G., EUTHANASIA, CAPITAL PUNISHMENT LETHAL INJECTION
          • K+ HAS LEAKED FROM ERYTHROCYTES
      • SLOW RISE  NERVE/MUSCLE CELLS LESS EXCITABLE
      • (Na+ CHANNELS INACTIVATED)
        • E.G., ALDOSTERONE HYPOSECRETION, RENAL FAILURE, ACIDOSIS
        • E.G., SUPPLEMENTAL K+ TO RELIEVE MUSCLE CRAMPS
  • ELECTROLYTE BALANCE
    • POTASSIUM HOMEOSTASIS: IMBALANCES
    • HYPOKALEMIA
      • NERVE/MUSCLE CELLS LESS EXCITABLE
      • MUSCLE WEAKNESS, LOSS OF MUSCLE TONE, DEPRESSED REFLEXES, IRREGULAR HEART ACTIVITY
      • E.G., HEAVY SWEATING, CHRONIC VOMITING OR DIARRHEA, EXCESSIVE LAXATIVES, ALDOSTERONE HYPERSECRETION, ALKALOSIS
      • E.G., DEPRESSED APPETITE, BUT RARELY FROM DIETARY INSUFFICIENCY
  •  
  • ELECTROLYTE BALANCE
    • CHLORIDE
    • MOST ABUNDANT ANION IN ECF
      • MAJOR CONTRIBUTION TO OSMOLARITY
    • ROLES
      • FORMATION OF HCl
      • CHLORIDE SHIFT
        • CO 2 LOADING/UNLOADING
      • REGULATION OF BODY pH
  • ELECTROLYTE BALANCE
    • CHLORIDE HOMEOSTASIS
    • Cl - STRONGLY ATTRACTED TO SOME CATIONS (E.G., Na + , K + , Ca 2+ )
      • CANNOT KEEP THEM APART
    • HOMEOSTASIS ACHIEVED AS AN EFFECT OF Na + HOMEOSTASIS
      • Cl - PASSIVELY FOLLOWS Na +
  • ELECTROLYTE BALANCE
    • CHLORIDE IMBALANCES
    • HYPERCHLOREMIA
      • RESULTS FROM DIETARY EXCESS
      • RESULTS FROM INTERVENOUS SALINE ADMINISTRATION
    • HYPOCHLOREMIA
      • SIDE EFFECT OF HYPONATREMIA
      • SIDE EFFECT OF HYPOKALEMIA
        • KIDNEYS RETAIN K+ BY SECRETING Na+, Cl- FOLLOWS
    • EFFECTS
      • ALTERED ACID-BASE BALANCE
  • ELECTROLYTE BALANCE
    • CALCIUM
    • ROLES
      • STRENGTHENS BONE
      • MUSCLE CONTRACTION
      • SECOND MESSENGER FOR HORMONES
      • ACTIVATES EXOCYTOSIS
      • BLOOD CLOTTING
  • ELECTROLYTE BALANCE
    • CALCIUM
    • BINDS TO PHOSPHATE ION
      • CAN FORM Ca 3 (PO 4 ) 2
      • HIGH CONCENTRATIONS OF BOTH IONS WILL FORM PRECIPITATE CRYSTALS
      • INTRACELLULAR [Ca 2+ ] MUST BE KEPT LOW
      • Ca 2+ PUMPED OUT & INTO E.R.
  • ELECTROLYTE BALANCE
    • CALCIUM HOMEOSTASIS
    • REGULATED BY PTH & CALCITROL
      • ALSO BY CALCITONIN IN CHILDREN
    • BLOOD [Ca 2+ ] REGULATED VIA
      • BONE DEPOSITION & REABSORPTION
      • INTESTINAL ABSORPTION
      • URINARY EXCRETION
  • ELECTROLYTE BALANCE
    • CALCIUM IMBALANCES
    • HYPERCALCEMIA
      • REDUCES EMBRANE PERMEABILITY TO Na+
      • INHIBITS DEPOLARIZATION OF NERVES/MUSCLES
      •  MUSCULAR WEAKNESS, CARDIAC ARRHYTHMI, ETC.
      • RESULTS FROM
        • ALKALOSIS
        • HYPERPARATHYROIDISM
        • HYPOTHYROIDISM
  • ELECTROLYTE BALANCE
    • CALCIUM IMBALANCES
    • HYPOCALCEMIA
      • INCREASES EMBRANE PERMEABILITY TO Na+
      • NERVES/MUSCLES OVERLY EXCITABLE
      •  TETANUS IF CONCENTRATION DROPS TO LOW
      • RESULTS FROM
        • ACIDOSIS
        • VITAMIN D DEFICIECY
        • DIARRHEA
        • PREGNANCY OR LACTATION
        • HYPOPARATHYROIDISM
        • HYPERTHYROIDISM
  • ELECTROLYTE BALANCE
    • PHOSPHATES
    • RELATIVELY CONCENTRATED IN ICF
    • ROLES
      • COMPONENTS OF BONES
      • COMPONENTS OF DNA & RNA
      • COMPONENTS OF PHOSPHOLIPIDS
      • ACTIVATE / DEACTIVATE ENZYMES
      • BUFFER pH OF BODY FLUIDS
  • ELECTROLYTE BALANCE
    • PHOSPHATES
    • COMPONENTS OF
      • NUCLEIC ACIDS (DNA, RNA)
      • NTPs AND dNTPs (ATP, dATP, GTP, dGTP, etc)
      • cAMP
      • PHOSPHOLIPIDS
      • VARIOUS OTHER PHOSPHORYLATED MOLECULES
    • GENERATED VIA ATP HYDROLYSIS, ETC.
    • EXIST AS MIXTURE OF THREE FORMS
      • PO 4 3- (PHOSPHATE ION)
      • HPO 4 2- (MONOHYDROGEN PHOSPHATE ION)
      • H 2 PO 4 - (DIHYDROGEN PHOSPHATE ION)
  • ELECTROLYTE BALANCE
    • PHOSPHATE HOMEOSTASIS
    • DIET PROVIDES AMPLE PHOSPHATE
    • READILY ABSORBED BY SMALL INTESTINE
    • REGULATION
      • RENAL TUBULES SITE OF REGULATION
      • PTH INCREASES PHOSPHATE EXCRETION
      • EXCRETION RATE AFFECTED BY URINE pH
  • ELECTROLYTE BALANCE
    • PHOSPHATE IMBALANCES
    • PHOSPHATE HOMEOSTASIS NOT VERY CRITICAL
    • BODY CAN TOLERATE WIDE VARIATIONS OF PHOSPHATEE CONCENTRATION WITH LITTLE EFFECT
  • ACID-BASE BALANCE
    • ACIDS, BASES, AND pH
    • ACID
      • ANY SUBSTANCE RELEASING H +
      • [H+] INCREASES (pH DECREASES)
    • BASE
      • ANY SUBSTANCE ACCEPTING H +
      • [H+] DECREASES (pH INCREASES)
    • pH
      • A MEASURE OF [H + ]
      • -LOG [H + ]
      • SCALE 0 – 14, 7 IS NEUTRAL
  • ACID-BASE BALANCE
    • WHY IS ACID-BASE BALANCE IMPORTANT?
    • METABOLISM REQUIRES NUMEROUS ENZYMES
    • ENZYMES ARE PROTEINS
    • pH AFFECTS PROTEIN STRUCTURE
    • PROTEIN STRUCTURE AFFECTS FUNCTION
    • DEVIATIONS FROM NORMAL pH CAN INACTIVATE ENZYMES AND SHUT DOWN METABOLIC PATHWAYS
  •  
  • ACID-BASE BALANCE
    • BLOOD pH
    • BLOOD AND TISSUE pH 7.35 – 7.45
      • ENZYMES FUNCTION WELL WITHIN THIS RANGE
      • ENZYMES FUNCTION POORLY (OR NOT AT ALL) WHEN SIGNIFICANTLY OUTSIDE OF THIS RANGE
      • THIS RANGE MUST BE MAINTAINED
        • ACID-BASE BALANCE
  • ACID-BASE BALANCE
    • BUFFERS
    • ANY MECHANISM OF RESISTING SIGNIFICANT CHANGES IN pH
    • ACCOMPLISHED BY CONVERTING:
      • STRONG ACID  WEAK ACID
      • STRONG BASE  WEAK BASE
  • ACID-BASE BALANCE
    • BUFFERS
    • PHYSIOLOGICAL BUFFER
      • SYSTEM STABILIZING pH BY CONTROLLING BODY’S OUTPUT OF ACIDS, BASES, OR CO 2
        • URINARY SYSTEM
          • BUFFERS GREATEST QUANTITY
          • REQUIRES HOURS OR DAYS TO EXERT EFFECT
        • RESPIRATORY SYSTEM
          • SMALLER EFFECT
          • EXERTS EFFECT WITHIN MINUTES
  • ACID-BASE BALANCE
    • BUFFERS
    • CHEMICAL BUFFER SYSTEM
      • COMBINATION OF WEAK ACID AND WEAK BASE
      • BINDS TO H + AS [H + ] RISES, AND
      • RELEASES H + AS [H + ] FALLS
      • CAN RESTORE NORMAL pH ALMOST IMMEDIATELY
      • THREE MAJOR CHEMICAL BUFFER SYSTEMS
        • BICARBONATE SYSTEM
        • PHOSPHATE SYSTEM
        • PROTEIN SYSTEM
  • ACID-BASE BALANCE
    • BICARBONATE BUFFER SYSTEM
    • CARBONIC ACID (H 2 CO 3 )
      • WEAK ACID
    • BICARBONATE ION (HCO 3 - )
      • WEAK BASE
    • CO 2 + H 2 0  H 2 CO 3  H + + HCO 3 -
    • WORKS IN CONCERT WITH RESPIRATORY AND URINARY SYSTEM
      • THESE SYSTEMS REMOVE CO 2 OR HCO 3 -
  • ACID-BASE BALANCE
    • PHOSPHATE BUFFER SYSTEM
    • DIHYDROGEN PHOSPHATE ION(H 2 PO 4 - )
      • WEAK ACID
    • MONOHYDROGEN PHOSPHATE ION (HPO 4 2- )
      • WEAK BASE
    • H 2 PO 4 -  H + + HPO 4 2-
    • STRONGER THAN BICARBONATE BUFFERING SYSTEM
    • MORE IMPARTANT IN BUFFERING ICF AND RENAL TUBULES THAN IN ECF
  • ACID-BASE BALANCE
    • PROTEIN BUFFER SYSTEM
    • PROTEINS ARE MORE CONCENTRATED THAN BICARBONATE AND PHOSPHATE BUFFERS
    • ACCOUNTS FOR ~75% OF ALL CHEMICAL BUFFERING OF BODY FLUIDS
    • BUFFERING ABILITY DUE TO CERTAIN FUNCTIONAL GROUPS OF AMINO ACID RESIDUES
      • CARBOXYL GROUPS
        • --COOH  -COO - + H +
      • AMINO GROUPS
        • --NH 3 +  -NH 2 + H +
  • ACID-BASE BALANCE
    • RESPIRATORY CONTROL OF pH
    • CO 2 + H 2 0  H 2 CO 3  H + + HCO 3 -
    • ADDITION OF CO 2 INCREASES [H + ]
    • REMOVAL OF CO 2 DECREASES [H + ]
    • CAN NEUTRALIZE 2-3 X MORE ACID AS CHEMICAL BUFFERS
  • ACID-BASE BALANCE
    • RENAL CONTROL OF pH
    • CAN NEUTRALIZE MORE ACID OR BASE THAN BOTH RESPIRATORY SYSTEM AND CHEMICAL BUFFERS
    • RENAL TUBULES SECRETE H +
      • H + EXCRETED IN URINE
      • EXCHANGED FOR SODIUM ION (Na + )
      • ONLY POSSIBLE WHEN [H + ] INSIDE TUBULE CELLS IS > [H + ] IN TUBULAR FLUID
  •  
  • ACID-BASE BALANCE
    • ACID-BASE BALANCE DISORDERS
    • AT pH 7.4, 20:1 HCO 3 - :H 2 CO 3 RATIO
    • IF [H 2 CO 3 ] INCREASES, pH DROPS
      • pH BELOW 7.35 = ACIDOSIS
    • IF [HCO 3 - ] INCREASES, pH INCREASES
      • pH ABOVE 7.45 = ALKALOSIS
  • ACID-BASE BALANCE
    • ACID-BASE BALANCE DISORDERS
    • RESPIRATORY ACIDOSIS
      • CO 2 PRODUCTION EXCEEDS RESPIRATORY CO 2 ELIMINATION
      • CO 2 ACCUMULATES IN ECF
      • pH DROPS
    • RESPIRATORY ALKALOSIS
      • RESPIRATORY CO 2 ELIMINATION EXCEEDS CO 2 PRODUCTION
      • EXCESSIVE VENTILATION (HYPERVENTILATION)
      • pH RISES
  • ACID-BASE BALANCE
    • ACID-BASE BALANCE DISORDERS
    • METABOLIC ACIDOSIS
      • INCREASED PRODUCTION OF ORGANIC ACIDS
        • E.G., FERMENTATION  LACTIC ACID
        • E.G., ALCOHOLISM, DIABETES MELLITUS  KETONE BODIES
      • INGESTION OF ACIDIC DRUGS
        • E.G., ASPIRIN
      • LOSS OF BASE
        • E.G., CHRONIC DIARRHEA, OVERUSE OF LAXITIVES
    • METABOLIC ALKALOSIS
      • RARE
      • OVERUSE OF BICARBONATES
        • E.G., ANTACIDS
      • LOSS OF STOMACH ACID FROM CHRONIC VOMITING
  •  
  • ACID-BASE BALANCE
    • ACID-BASE BALANCE DISORDERS
    • ACIDOSIS
    • H + PASSIVELY DIFFUSES INTO CELLS
    • K + DIFFUSES OUT
      • ELECTRICAL BALANCE MAINTAINED
    • H + BUFFERED BY INTRACELLULAR PROTEINS
    • NET LOSS OF CATIONS FROM CELL
    • MEMBRANE IS NOW HYPERPOLARIZED
    • NERVE & MUSCLE CELLS DIFFICULT TO STIMULATE
      • CENTRAL NERVOUS SYSTEM DEPRESSED
        • CONFUSION, DISORIENTATION, COMA
  •  
  • ACID-BASE BALANCE
    • ACID-BASE BALANCE DISORDERS
    • ALKALOSIS
    • H + PASSIVELY DIFFUSES OUT OF CELLS
    • K + DIFFUSES INTO CELLS
      • GAIN IN POSITIVE INTRACELLULAR CHARGE
    • MEMBRANE POTENTIAL SHIFTED
    • NERVOUS SYSTEM HYPEREXCITABLE
      • NEURONS FIRE SPONTANEOUSLY
      • SKELETAL MUSCLES OVERSTIMULATED
        • MUSCLE SPASMS, TETANY, CONVULSIONS, RESPIRATORY PARALYSIS
  • ACID-BASE BALANCE
    • ACID-BASE IMBALANCE COMPENSATION
    • RESPIRATORY SYSTEM COMPENSATION
    • ADJUSTS P CO 2 IN ECF
      • CO 2 EXCESS  INCREASED VENTILATION
      • CO 2 DEFICIENCY  DECREASED VENTILATION
    • EFFECTIVE VS RESPIRATORY ACIDOSIS AND ALKALOSIS
    • NOT VERY EFFECTIVE VS METABOLIC ACIDOSIS AND ALKALOSIS
      • I.E., CANNOT RID BODY OF KETONE BODIES
    • CAN CORRECT pH 7.0 TO 7.2 OR 7.3
      • NOT ALL THE WAY TO 7.4
  • ACID-BASE BALANCE
    • ACID-BASE IMBALANCE COMPENSATION
    • RENAL SYSTEM COMPENSATION
    • SLOWER TO RESPOND
    • CAN FULLY RESTORE NORMAL pH
    • URINE pH NORMALLY 5 – 6
      • MAY DROP TO 4.5 WITH EXCESS H +
        • RESPONSE TO ACIDOSIS
        • RENAL TUBULES INCREASE H + SECRETION
        • H + IN URINE IS BUFFERED
      • MAY RISE TO 8.2 WITH EXCESS HCO 3 -
        • RESPONSE TO ALKALOSIS
        • HCO 3 - CONCENTRATION IN URINE ELEVATED