pH, Electrolyte, & Fluid Balance (exam 3) Flashcards
What is the total body water (TBW)?
All fluids 60% of weight
How much of the TBW is intracellular fluid (ICF)?
2/3 of the TBW
How much of the TBW is extracellular fluid (ECF)?
1/3 of the TBW
What makes up the ECF?
Interstitial fluid (IF): between the cells Intravascular fluid: blood plasma (primarily H20) Lymph, synovial, intestinal, CSF, sweat, urine, pleural, peritoneal, pericardial, intraocular fluid
What is the normal pH of the body?
7.40
What is the normal pH range in the body?
7.35 - 7.45
What is pH a measure of?
H+ ions
Power of hydrogen
0-14
What pH is acidic (acidotic)?
7.34 and below
What pH is basic (alkadotic)?
7.46 and above
What is an anion?
Negative charged ion
What is a cation?
Positively charged ion
plussy cat
What is the primary ECF cation? Where is there more of it?
Sodium (Na+)
More outside the cell
What does Na+ do?
Regulates osmotic forces
Fluid Movement! water follows Na+
What is the primary ECF anion?
Chloride (Cl-)
What does Cl- do?
Provides electroneutrality
Moves with Na+
What does H20 do when Na+ levels are increased?
H20 levels increase
What does H20 do when Na+ levels are decreased?
H20 levels decrease
What is tonicity?
Change in concentration of solutes (salt) with relation to solvent (water)
What is an isotonic solution?
Equal concentrate in and outside the cell
What is a hypertonic solution? Which direction does water move?
Concentrate higher outside the cell
Water moves out of the cell (dehydrates cell)
What is a hypotonic solution? Which direction does water move?
Concentrate higher inside the cell
Water moves into cell (explodes/ lysis cell)
What is hypernatremia? What are the manifestations?
Na+ > 145 mEq/ L High Na+ levels (outside cell) Intracellular dehydration Increase Na+ or decrease H20 Manifestations: increase cellular functions Hypertension
What is hyponatermia? What are the manifestions?
Na+ < 135 mEq/ L Low Na+ levels More H20 into cells Decrease Na+ or increase H20 Manifestations: decrease cellular functioning, hypotension, tachycardia (try to bring up BP)
What is the most common electrolyte imbalance?
Hyponatremia
What is hypochloremia the result of?
Result of hyponatremia or
Increase HCO3
What is the major intracellular electrolyte?
Potassium (K+)
What does K+ do?
Think heart
Transmission and conduction of nerve impulses
Normal cardiac rhythm
Skeletal and smooth muscle contractions (“action potentials”)
Changes in K+= changes in heart functioning
What is acidosis? Causes of acidosis?
pH under 7.35
Increase H+ inside cell –> K+ moves out (hyperkalemia)
What is hyperkalemia? What are its manifestations?
K+ moves out
High K+ levels outside cell
Raises resting membrane potential
Increase excitability: take less to reach threshold
Manifestations: cardiac dyshythmias, PVC (premature ventricular contractions)
What is alkolosis? Causes of alkolosis?
pH above 7.46
Decrease H+ inside cell –> K+ moves into cell (hypokalemia)
What is hypokalemia? What are its manifestations?
Low K+ outside the cell
Lowers resting membrane potential
Decrease excitability: need more to reach threshold
Manifestations: cardiac dysrhythmias (bradycardia, asystole)
What is Ca++ function? Hypocalcemia? Hypercalcemia?
Think skeletal muscle function
Affects threshold potential
Hypocalcemia: decrease threshold potential= more excitable (increase skeletal muscle function)
Hypercalcemia: increase threshold potential= less excitable (decrease skeletal muscle function)
What is the main driver of fluid balance?
Na+
What primarily regulates fluid balance?
Kidneys and Hormones
What regulates H20?
Hypothalamus–> posterior pituitary–> ADH
ADH causes kidneys to take H20 from the urine
What regulates Na+/ Cl-?
Adrenal gland- releases aldosterone: reabsorbs Na+, H20, decrease urine, increase BP
Atrial muscle- releases natriuretic hormones (ANH): put Na+ into urine, H20 follows, increase urine, decrease BP
What is osmolarity/ osmolality? What happens if increased?
Amount of electrolytes to H20
Increase osmolality: More electrolytes, less H20
What does the RAAS system do?
Release aldosterone
Increase BP
Decrease urine
How do we take in fluids?
Drinking
Food
Metabolism
How do we output fluids?
Urine
Breathing
Skin
Feces
What is hydrostatic pressure?
Fluid pressure (main= BP) PUSHing force (high to low)
What is oncotic pressure? Osmotic pressure?
Oncotic= Proteins
Osmotic= Electrolytes
PULLing force
What is capillary hydrostatic pressure (CHP)?
‘Fluid out’
#1 pressure (strongest)
Push out of capillary
Blood pressure is driving force out
What is capillary oncotic pressure (COP)?
'Fluid in' #2 pressure Water attraction to plasma proteins Albumin is driving force into capillaries Pull into capillary
What is interstitial hydrostatic pressure (IFHP)?
'Fluid in' # 3 pressure Interstitial fluid pressure Push into capillaries Driving force is interstitial fluid pressure
What is interstitial oncotic pressure (IFOP)
‘Fluid out’
#4 pressure (weakest)
Water attraction to interstitial proteins
Proteins and electrolytes are driving force out
Pull into interstitial fluid
What pressures work together?
CHP & IFOP
COP & IFHP
What is edema?
Excessive accumulation of fluids in interstitial space
What are the 4 major causes of edema?
Increase capillary hydrostatic pressure: Increase BP
Decrease plasma oncotic pressure
Increase capillary permeability: inflammation
Lymph obstruction: can’t drain obligatory load
What pH range is the absolute range of life?
6.8-7.8
Acid pull K+ from cells- hyperkalemia
Base push K+ into cells- hypokalemia
Are acids or bases produced more in the body?
Acids
What constantly regulates acids in the body?
Lungs: increase or decrease CO2
Kidneys: bicarbonate & H+ ions
What is the volatile acid? How is it eliminated? What carries out the volatile body acids?
Carbonic acid (H2CO3) only one
Eliminated as CO2
Carried out by the lungs
What carries out the nonvolatile body acids
Eliminated by the kidneys
When the blood pH is low, what is it called?
Acidemia
When the blood pH is high, what is it called?
Alkalemia
What is acidosis?
Low pH in general body tissues
What is alkalosis?
High pH in general body tissues
What is metabolic acidosis? Signs & Symptoms?
Low body pH
Kidney problem: retain to much H+ or get rid of to much bicarb
Hyperkalemia (high K+)
Kussmaul respirations (compensatory hyperventilation)
What is metabolic alkalosis? Signs and Symptoms?
High body pH
Kidney problem: retain to much bicarb or get rid of to much H+
Compensatory hypoventilation
Hypokalemia (low K+)
What is respiratory acidosis? Signs and Symptoms?
Low body pH
Lung problem: not getting rid of enough CO2
Hypoventilation–> hypoxia
Hyperkalemia (high K+)
What is respiratory alkalosis? Signs and Symptoms?
High body pH
Lungs problem: blow off to much CO2
Hyperventilation
Hypokalemia (low K+)
What is a buffer?
A chemical that binds to excess H+ or OH- without a significant change in pH
What are the physiological pH control systems?
Chemical buffer systems: immediate (blood) response, ex: bicarbonate buffer system is main (produced by H2O & CO2)
Physiological buffer systems: minutes (lungs) response, hours (kidneys), ex: respiratory or renal response system
What is compensation in reference to the buffering systems?
If lungs or kidneys aren’t working right the other compensates (after trying blood buffer)
Respiratory issue- kidney compensation
Kidney issue- lung compensation
What is the normal range of pCO2?
35-45 mmHg
46 or high= acid
34 or below= base
What is the normal range of HCO3?
22-26 mEq/ L
What does acidosis do to CNS?
CNS depression
Stupor to confusion to coma
What does alkylosis do to CNS?
CNS irritability
Restlessness to seizures
What does it mean for fluid balance if:
CHP + IFOP > COP + IFHP?
More fluid into interstitial fluid from the blood
What does it mean for fluid balance if:
CHP + IFOP < COP + IFHP?
More fluid pushes into the capillaries
What pathologies are related to fluid balance errors?
4 causes of edema:
Increase capillary hydrostatic pressure: Increase BP
Decrease plasma oncotic pressure
Increase capillary permeability: inflammation
Lymph obstruction: can’t drain obligatory load
What is the obligatory load?
During fluid balance process, 10% of fluid goes into tissues and can’t be reabsorbed due to BP
Fluid must be drained by lymphatics
Obligatory load= 10% of fluid that isn’t reabsorbed
