PH, Electrolyte, and Fluid Balance Flashcards
distribution of fluids in the body
- total body water - all fluids are 60% of body weight (your weight x .6 = lbs of water)
- intracellular fluid ICF - 2/3 total body weight (inside cells)
- extracellular fluid ECF - 1/3 total body weight
- interstitial fluid: between cells
- intravascular fluid: blood plasma in vessels
- lymph, synovial, intestinal, CSF, sweat, urine, pleural, perioteoneal, pericardial and intraocular fluids
body’s PH
- 7.35-7.45
- basic
- PH = power of hydrogen. PH measures hydrogen in body
Sodium/Chloride Balance
SODIUM (Na+)
- primary extracellular fluid (ECF) cation
- regulates osmotic foces
- role = fluid movement - neuromuscular irritability, acid-base balance, cellular reactions, membrane transport
- WATER always move with Na+*
CHLORIDE (Cl-)
- primary ECF anion
- provides electroneutrality
anion
negatively charged ion
cation
positively charged ion
tonicity
change in concentration of solutes (salt) with relation to solvent (water)
- isotonic: ECF = 0.9% NaCl
- hypertonic - ECF >0.9% NaCl. cells SHRINK. more solutes outside of cell than in. H2O moves out of cell with Na+
- Hypotonic - ECF <0.9% NaCL. cells SWELL. more solute into cell. can cause cells to lyse.
Sodium Na+
- regulation of fluid balance - VERY important electrolyte
- most abundant positive ion (cation)
- 90% ECF cations
- Hypernatremia: more na+ outside of cell ECF
- Hyponatremia: less na+ outside the cell ECF
Hypernatremia
- dehydration - pulls water out of cell
- more Na+ than water
- intracellular dehydration, hypertension (hypervolemic = higher volume of blood)
- H20 movement from ICF to ECF (interstitial)
- Causes: diabetes, diarrhea
- manifestations: increased cellular functioning - convulsions, thirst, fever, muscle twitching, hyperreflexia
hyponatremia
- less Na+ and more H20
- decreased BP, decreased cell fun
- Casues: vomiting, diarrhea, GI scution, burns, diuretics
- manifestations: decreased functioning - lethargy, confusion, depressed reflexes, seizures, coma, hypotension, tachycardia, decreased urine output
chloride Cl-
- primary ECF anion
- electroneutrality with Na+
- Hypochloremia: result of hyponatremia or increased HC03
- vomiting = loss of hydrochloric acid = loss of Cl- in blood
- cystic fibrosis: imbalance of Na+ and Cl- transport across epithelium
potassium K+
- major intracellular electrolyte 98% intracellular, Na/k ATPase Pump
- affects resting membrane potential
- transmission and conduction of nerve impulses, normal cardiac rhythm, skeletal and smooth muscle contractions, “action potentials”
K+ and PH
- change in PH greatly affects k+ balance
- acidosis causes: increase in H+ inside cell -> k+ moves out of the cell
- more H+ outside cell –> H+moves into cell –> k+ is pulled out
- acidosis = hyperkalemia
- Alkolosis causes: decrease in H+ inside cell –> k+ into cell
- increased PH in tissue and blood pushes K+ into cell
- alkalosis = hypokalemia
hypokalemia
- harder to start and action potential with low K+
- lower resting membrane potential = less excitable cell
- low K+ outside of cell
- Causes: low intake of k+, increased loss of K+, increased K+ flow into cell
- manifestations: heart cells are less excitable, weakness, atrophy, cardiac dysrhythmias,
- decresed K+ causes decreased rest membrane potential causes decreased heart function
hyperkalemia
- increased k+ outside cell = increased excitability
- increased resting membrane potential
- causes: increased shift from ICF (acidosis), decreased renal excretion
manifestations: - mild heart attacks = increased neuromuscular irritability/activity. tingling of lips & fingers, restlessness, intestinal cramps/diarrhea
- severe attacks = no repolarization = muscle weakness, decreased tone, flaccid paralysis, cardiac dysrhythmias, PVCs
big picture of electrolytes
- low K+ = decreased excitability. Bradycardia, asystole
- high K+ = increased excitability. cardiac dysrhythmias, PVC
- low Ca+ = increased muscle excitability, decreased threshold, cramps, twitches
- High Ca+ = decreased muscle excitability, increased threshold, less excitable
calcium Ca+
- needed for bone, teeth, blood clotting, muscle contractions, neurotransmitter release, hormone secretion, cell receptor function 99% in bone
- affects THRESHOLD potential
- Hypocalcemia = decreased block of Na into cell
- increased neuromuscular excitability
- decreased threshold means more excitable
- increased muscle function
- Hypercalcemia = increased block of Na into cell = decreased neurotransmitter excitability
- increased threshold potential = less excitable
- muscle weakness, cardiac arrest, kidney stones, constipation
- decreased muscle function
fluid balance
sodium, calcium, and water regulation
- primarily regulated by kidneys and hormones
- water
- hypothalamus –> posterior pituitary –> ADH (antidiuretic hormone - tells kidneys to reabsorb more water out of urine)
- Na/Cl
- adrenal gland –> aldosterone
- atrial muscle –> naturetic hormones (ANH)
- aldosterone = reabsorbs na+ in kidney (H20 goes with it), causes decreased urine, increased BP
- naturetic hormone = increases urine, decreases BP. antagonistic to Aldosterone. puts more na+ and H20 into urine
ADH Functions
Antidiuretic Hormone
decreased circulating fluid volume –> increased thirst & ADH secretion –> increased fluid intake and decreased water excretion –> increased renal water retention –> increased circulating fluid –> decreased plasma osmolality –> decreased ADH and decreased thirst
RAAS Pathway
- release of renin causes release of aldosterone
- renin-angiotensin-aldosterone system
- a hormone system that regulates blood pressure and water (fluid) balance
- sodium balance in kidneys
naturetic hormone
ANH
increase in total body na+ –> increased drinking, osmotic shift of water out of cells –> increased plasma volume –> increased atrial stretching detected by atrial endocrine cells –> ANH releases –> GFR (filtration rate) increases, decrease renin angiotensin-aldosterone, decreased na+ absorption
balance of fluids
metabolism: glucose (eat) + O2 (breath) = CO2 + H2) + ATP
INTAKE: metabolism (400, produces fluid for us), food (500), drinking (1500)
OUTPUT: faeces (100), skin (400, sweat), breathing (400, water releases), urine (1500)
fluid “tug of war”
HYDROSTATIC PRESSURE: pushing force
- move from high to low
- fluid pressure = BP
ONCOTIC/OSMOTIC: pulling force
- driven by proteins or electrolytes
- electrolytes pull water into cell
- plasma proteins are negatively charged
fluid movement between ICF and ECF
- water, nutrients, and waste products
between capillaries and interstitial space - CHP + IFOP - work together
- COP + IFHP - work together
- CHD + IFOP > COP + IFHP = blood from caps into IF
- CHD + IFOP < COP + IFHP = blood from IF into caps
- Capillary Hydrostatic Pressure
- strongest
- PUSH from capillaries into interstitial fluid
- blood pressure = fluid out - Capillary Oncotic Pressure
- PULL from intersistial fluid into capillaries
- water attract to plasma proteins (albumin) = fluid in - Interstitial hydrostatic pressure
- PUSH from IF fluid into caps = fluid in - interstitial oncotic pressure
- weakest
- PULL into IF fluid
- water attraction to interstitial proteins = fluid out
- obligatory load: 10% of fluid in tissues cannot be reabsorbed into blood. COP isn’t as strong as CHP. IF Fluid drained by lymphoma
Edema
excessive accumulation of fluids in interstitial space
4 major causes:
- increased capillary hydrostatic pressure
- increased BP = increased edema
- venous obstruction (DVT, hepatic obstruction), salt and water retention (heart, renal failure, hypertension) - decreased plasma oncotic pressure
- decreased albumin (water soluble protein) - liver disease, malnutrition, kidney disease, burns, hemorrhage
- decreased albumin = increased edema - increased capillary permeability
- trauma, burns, neoplastic (tumorous), and allergic reactions
- increased inflammation = increased edema - lymph obstruction
- removal of nodes (surgery), inflammation or tumors
- 10% of fluid builds up in IF = edema
PH
power of hydrogen 0-14 0 = acidi 14 = basic 7 = neutral 7.4 = bio neutral 7.35-7.45 (basic) each numberic goes up by 10X the PH range of life 6.8-7.8 acidic = hyperkalemia basic = hypokalemia
acids
formed as end products of protein, carb and fat metabolism
- major regulatory organs; bone, LUNG, KIDNEYS< blood
- hydrochloric acid, carbonic acid
- BIcarbonate (HCO3) carries CO2 and blood buffer
body acids
two forms:
VOLATILE: H2CO3 - gaseous and airborn, CO2, lungs
NONVOLATILE: eliminated by kidneys, sulfuric, phosphoric
2 most important regulatory systems for fluid, electrolyte and PH balance?
LUNGS: C02 blows off acid, regulates acidity
KIDNEYS: biarbonate HC03 and H+ ions.
- low blood PH = academy
- general acidity = acidosis
- high Blood PH = alkalemia
- general high PH = alkalosis
metabolic acidosis
kidneys retain H+ and rids too much bicarb
- low body PH
metabolic alkalosis
retain more bicarb and rid H+
- high body PH
respiratory acidosis
hypoventilation
- not expelling enough CO2 (acid)
respiratory alkalosis
- blowing off too much CO2 (acid)
- hypervntilation
buffer
- any substance that doesn’t allow a drastic change in PH. a chemical that binds excess H+ or OH- without any significant change in PH
- 1st line = chemical buffer = BLOOD
- immediate
- bicarbonate buffer system
- phosphate buffer system
- protein buffer system - 2nd line = LUNGS - physiological buffer
- minutes
- respiratory response system - 3rd line = KIDNEYS = physiologic
- hours
- H+ and Bicarb
- renal response system
* compensation
- PROTEINS also work as a buffer and PHOSPHATE
- best blood buffer is a mix of C02 and Bicarb
acidosis
- too much CO2 or too little HCO3
- lower PH
1. CO2 increases with hypoventilation (pneumonia, emphysema)
2. Metabolic conditions = ketoacidosis due to access fat metabolism (diabetes mellitus) which will lower bicarb - too much CO2 = issue with lungs
- too little HCO3 - issue with kidneys
alkalosis
- too much HCO3 or too little CO2
- higher PH
1. Co2 decrease via hyperventilation (respiration blows off co2)
2. Emesis (vomiting) removes stomach acid and raises bicarb - too little CO2
- too much HCO3
compensation
- if kidneys aren’t working - respiratory compenstates by increasing or decreasing CO2
- if lungs aren’t working - kidneys compensate by increasing or decreasing acidity/alkalinity of urine
metabolic acidosis
- kidneys retain too much H+ or secrete too much bicarb
- hyperkalemia
- increased respirations - hyperventilations
- acidic fruity breath
- causes: severe diarrhea, renal failure, shock
metabolic alkalosis
- decreased acid or increased base
- decreased respirations, hypoventilation
- hypokalemia
- causes: vomiting, diruretics
respiratory acidosis
- retention of CO2 by lungs
- hypoventilation, hypoxia
rapid, shallow respirations - hyperkalemia
- causes: pneumonia, COPD, atelectasis
respiratory alkalosis
- increased loss of CO2 from lungs
- increased respirations, hyperventilation
- hypokalemia
- causes: hypoventilation (anxiety, fear), mechanical ventilation
normal values
PH = 7.35-7.45 pCO2 = 35-45 HCO3 = 22-26