Chapter 41 F&E Flashcards
Intracellular
Fluids within cells; 42% of total body weight; 2/3 of total body= water
Extracellular
Fluids outside of cells; 17% of body weight; 1/3 of total body weight
3 Extracellular Compartments
Interstitial, Intravascular, Transcellular
Interstitial
between cells
Intravascular
plasma
Transcellular
fluid separated by barrier
Electrolytes
An element or compound that, when dissolved or dissociated in water or solvent, separates into ions
Cations
Positive Charge; Na+(sodium), K+(potassium), CA2+(calcium)
Anions
Negative Charge; Cl-(chloride), HCO3-(bicarbonate), SO4-(sulfate)
Potassium (K+)
Normal range 3.5-5 mEq/L;
Major factor in ICF; Responsible for key metabolic & muscular activity-including cardiac conduction; Regulated by dietary intake & renal excretion
Sodium (Na+)
Normal range 135-145 mEq/L;
Most abundant in ECF; Major contributors to water balance; regulated by dietary intake and aldosterone secretion
Normal Arterial Blood pH
7.35-7.45
Osmosis
Movement of a solvent across a semi-permeable membrane from an area of lesser to one of greater concentration.
Diffusion
Random movement of a solute through a semi-permeable membrane from higher to lower concentration. (ie. oxygen & carbon dioxide)
Filtration
Movement of water and diffusable substances across a membrane together, under pressure, from higher to lower pressure.
Active Transport
Movement of ions against osmotic pressure to an area of higher pressure. Requires energy. (ie. sodium potassium pump)
Acidosis
Excess of hydrogen ions in the ECF (below 7.35)
pH decreases; respiratory, renal, or metabolic cause; ECF becomes acidic
Alkalosis
lack of hydrogen ions (above 7.45)
ECF becomes alkaline; pH increases, hyperventilation; vomiting; excess ingestion of base (antacids)
Hydrogen Ion Regulators
- Buffer systems
- Respiratory
- Kidneys
Buffer
A substance or group of substances that can absorb or release H+ (lungs, heart, kidneys)
Acidic
More H+, pH less than 7.35
Chemical Acid-Base Balance Regulation
Carbonic Acid and bicarbonate buffer system; Reacts in seconds to change ECF pH; ECF becomes more acidic, pH decreases, producing acidosis; ECF receives more base, pH increases, producing alkalosis
Biological Acid-Base Balance Regulation
Occurs when hydrogen ions are absorbed or released by cells; Occurs after chemical buffering; Ion exchange: with excess acid H+ enters the cell, K+ leaves, enters ECF producing increased serum K+ (ketoacidosis and starvation)
Physiological Acid-Base Balance Regulation
Buffers are located in lungs and kidneys; healthy ones act to return pH to normal; lungs correct imbalance by altering rate and depth of respiration; kidneys increase or decrease HCO3- production (reabsorb or excrete) and excrete H+
Lungs
Control excretion of CO2
Kidneys
Control excretion of H+ and HCO3-
Alkalosis; pH would increase because person is getting rid of CO2 (associated with acid)
Hyperventilating
Isotonic
same osmality as blood
Hypertonic
higher osmotic pressure; pulls fluid from cells (Cells shrink)
Hypotonic
lower osmotic pressure, fluids go in cell to enlarge
Fluid Intake for Regulation of Body Fluids
Regulated by thirst; intake is about 2200-2700 ml/day; requires an alert state
ADH (water retention); Renin angiotensis-aldosterone mechanism (sodium and water retention to help increase blood volume); atrial natriuretic peptide (ANP) - diuretic that cause sodium loss and inhibit thirst mechanism
Hormonal Regulation of Body Fluids
Lost through kidneys, skin, lungs, gi tract; insensible loss through lungs and skin; sensible loss excessive perspiration
Fluid Output for Regulation of body fluids
Fluid & Electrolyte Imbalances (6)
Hypo and hypernatremia
Hypo and hypermagnesemia
Hypo and hyperkalemia
