Fluids & Electrolytes Test Review PDF

Fluids & Electrolytes Test Review Fluid & Electrolyte Definition Fluid: water and all dissolved substances in the body’s fluid compartments Electrolyte: substances that dissociate in water to form ions controls osmosis between f...

Fluids & Electrolytes Test Review Fluid & Electrolyte Definition Fluid: water and all dissolved substances in the body’s fluid compartments Electrolyte: substances that dissociate in water to form ions controls osmosis between fluid compartments, maintains acid-base balance, & carries electric current which is necessary for enzyme activities Non-electrolytes: substances that do not dissociate in solutions, not electrically charged, & are mainly organic compounds (ex. lipids, glucose, urea, & creatinine) The homeostasis of cells depend on the balance/homeostasis of fluids & electrolytes in the body fluid & electrolyte mechanisms regulate total volume, fluid distribution, solute concentrations, and pH can lead to death if not balanced & regulated Body’s Fluid Compartments ICF: Intracellular fluid — fluid within cells (ex. cytoplasm) ECF: Interstitial fluid & blood plasma (intravascular fluid) Interstitial: fluid surrounding cells & blood vessels Intravascular: fluid within arteries & veins (blood) Body Fluid Distribution Women: 45% solids, 55% liquids Men: 40% solids, 60% liquids 2/3 of the body’s fluids is intracellular 1/3 consists of extracellular fluid 80% interstitial, 20% blood plasma Composition of Body Fluids Fluid Na+ HCO3- HPO42- Protein Potassium Cl- Compartment Intracellular Low None High High High Low Interstitial High High None None Low High Intravascular High High None High Low High Movement of Fluid: Intravascular → Interstitial Sterling’s Law of the Capillary: describes the movement of fluid from intravascular to interstitial & eventually intracellular. Involves 3 main processes: Filtration, Reabsorption, & Lymphatic Capillaries Fluids & Electrolytes Test Review 1  Filtration: Blood hydrostatic pressure pumps fluids, solutes, & albumin down the arteriole end of the capillaries. Fluid & solutes get pushed towards & out capillaries semi-permeable membrane. Albumin stays behind because capillary membrane only allows water & small particles through Reabsorption: Albumin left behind capillary wall generates osmotic pressure, creating a concentration gradient that draws fluid back into bloodstream. Eventually, concentrations even out and fluid being drawn back in slows & stops Lymphatic Capillaries: Excess fluid left behind in interstitial space gets soaked up by lymphatic capillaries & eventually sent back into bloodstream Movement of Fluid: Interstitial → Intracellular Active Transport: protein carriers, pumps, & channels used to carry ions in/out a cell. Requires ATP. Cells obtain water by using a sodium/potassium pump to kick out K+. This allows in Na+ where water follows the solute Cells lose excess water by kicking out Na+ using active transport, water follows the solute out of the cell Passive Transport: molecules & fluids pass through the cell membrane by moving with the concentration gradient. Doesn’t require ATP. Osmosis: the movement of water in/out the cell Facilitated Diffusion: the movement of larger molecules in/out the cell w/ the help of carrier/channel proteins Diffusion: nutrients, gases & waste moves along the concentration gradient to pass cell membrane Fluid Balance Water gain & loss needs to be of the same amount (loss=gain) Water is typically gained through ingestion, & loss through urine, feces, sweat, breath Main regulation of water gain is intake adjustment Fluid Intake Regulation: controlled by thirst mechanism, RAAS, & ADH hormone raises blood pressure/volume Fluid Output Regulation: controlled by ANP lowers blood pressure/volume Thirst Mechanism thirst center in hypothalamus gets triggered by: decrease in saliva production increase in blood osmolarity decrease in blood volume calls for us to drink, which restores body’s water RAAS Fluids & Electrolytes Test Review 2  1. Liver produces angiotensinogen 2. Kidneys produce renin once stimulated by dehydration symptoms (decrease in blood volume, increase in blood osmolarity) 3. Angiotensinogen & renin interact to produce angiotensin 1 4. Angiotensin 1 gets converted into angiotensin 2 using ACE enzyme from lungs 5. Angiotensin 2 stimulates adrenal cortex to produce aldosterone 6. Aldosterone calls for kidneys to reabsorb Na+, in which leads to water reabsorption because water follows solute a. End result: increased blood volume, decreased blood osmolarity ADH Hormone 1. ADH hormone gets released by hypothalamus when stimulated by dehydration (decrease in blood volume, increase in blood osmolarity) 2. ADH hormone calls for kidneys to hold onto/retain water a. End results: increased blood volume, decreased blood osmolarity ANP triggered by abnormal increase in blood pressure/volume Increase blood volume causes heart walls to stretch, which stimulates the atrial cells to produce atrial natriuretic peptide (ANP) ANP reduces the release of renin by the kidneys, which inhibits RAAS from occurring End results: decreased blood volume/pressure, decrease in aldosterone production, decrease in Na+ absorption, increase in urine output Fluid Imbalances Edema: abnormal fluid accumulation in interstitial space can be caused by 4 mishaps of Sterling’s Law of the Capillary: venous pressure, hypoproteinemia, inflammation, lymphatic obstruction Effusion: abnormal fluid accumulation in body cavities Pleural Effusion: fluid accumulation in thoracic cavity Ascites: fluid accumulation in abdominal cavity, due to any cause of edema Edema Causes Venous Pressure: compression of venule end of capillaries, creating a backlog & increasing filtration pressure. More fluid getting pushed out of capillary wall, not enough getting drawn back in causing fluid accumulation in interstitial space Hypoproteinemia: low protein levels in blood, meaning not enough albumin to generate osmotic pressure for reabsorption of fluids. Filtration still occurs & fluid accumulates in interstitial space, causing edema Fluids & Electrolytes Test Review 3  Inflammation: white blood cells burst through capillary wall to defend, causing the capillary wall to become more permeable. More fluid gets filtered out during filtration, causing an accumulation in interstitial space. If severe enough, albumin could escape capillary wall, causing hypoproteinemia which decrease osmotic pressure & reabsorption of fluids Lymphatic Obstruction: damaged lymphatic capillaries lose the ability to soak up excess fluid left in interstitial space after reabsorption concentrations even out, causing excess fluid to build up & accumulate in interstitial space Electrolyte Imbalances Sodium: most abundant cation in ECF, important for action potentials & water reabsorption Potassium: most abundant cation in ICF, important for action potentials & fluid (water) balance Calcium: important for neurotransmitter release & sliding filament theory Chloride: most abundant anion in ECF, important for balancing anions between fluid compartments & can easily move between ICF & ECF Bicarbonate: abundant in ECF, important for transporting CO2 through bloodstream & important buffer in plasma Imbalance Causes Signs/Symptoms Imbalance Causes Signs/Symptoms Decreased Dehydration, Thirst, dry mouth, sodium intake or Hypernatremia: increased sodium Hyponatremia: headaches, decreased urine increased sodium Increased Na+ intake or decreased Decreased Na+ confusion, nausea output loss. Excess sodium loss water in body Muscle weakness, Muscle fatigue, Renal failure, cardiac Vomiting, cardiac arrythmia, excessive intake, arrythmias, diarrhea, cardiac arrest, Hyperkalemia aldosterone Hypokalemia cardiac arrest, nasogastric, shallow deficiency, or tissue respiratory diuretics respiration, damage distress increased urine Increased Constipation, Increased PTH loss/decreased anorexia, nausea, numbness, tingly (tumors), Paget’s intake of Ca+, Hypercalcemia vomiting, polyuria, Hypocalcemia finger, tetany, disease, excess removal of PTH polydipsia, fractures vitamin D glands, vitamin D hypertension deficiency Excessive lethargy, Muscle spasms, Dehydration, vomiting, weakness, metabolic increased chloride overhydration, metabolic alkalosis, shallow Hyperchloremia intake, severe renal Hypochloremia aldosterone acidosis, rapid respirations, failure, deficiency, and deep hypotension, & hyperaldosteronism congestive heart breathing tetany failure Fluids & Electrolytes Test Review 4