Fluid, Electrolyte, and Acid-Base Balance Flashcards
What is fluid and Electrolyte balance?
The process of regulating the extracellular fluid volume, body fluid osmolality, and plasma concentrations of the electrolytes.
What is acid-base balance?
The process of regulating the pH, bicarbonate concentration, and partial pressure of carbon dioxide of body fluids.
What are the 3 main characteristics of fluids that must be kept in balance in order to maintain normal cell function?
- Amount of fluid (volume).
- Concentration of fluid (osmolality).
- Composition - electrolyte concentration and acid/base balance of that fluid.
What is osmolality?
Osmolality is the number of particles per kilogram of H2O. Osmolality is reported as a solute in H2O specifically.
What is tonicity?
Tonicity is related to the effect the fluid would have on a cell as a result of the permeability of the membrane to the solute.
What is isotonic?
Isotonic fluid is equal to the osmolality of blood. It doesn’t change the volume of the cell.
What percentage of a normal male’s body is composed of H2O?
A normal male’s body is composed of 60% H2O. A male’s percentage of H2O is greater than a female’s.
What populations of humans are composed of a lower percentage of H2O?
The elderly. H2O percentage decreases with age. The obese. Fat holds less H20 than muscle. The obese have a lower percentage of H20. Most at risk, obese and elderly patient.
What are the two main types of body fluid?
The two main types of body fluid are: intracellular fluid and extracellular fluid.
What is intracellular fluid?
Intracellular fluid is found within the cells, contains the electrolytes: potassium, phosphate, sulfate, and is 2/3 of adult fluid volume.
What electrolytes exist intracellularly?
Intracellular electrolytes are: potassium, sulfate, and phosphate.
What is extracellular fluid?
Extracellular fluid is all fluid that is found outside of the cells. Electrolytes that exist in the extracellular fluid are: sodium, chloride, and bicarbonate (HCO3). 1/3 of total adult fluid volume.
What are the 4 types of extracellular fluid?
The 4 types of extracellular fluid are: intravascular, interstitial, lymph and transcellular.
What does intravascular fluid consist of?
Extracellular intravascular fluid consists of the liquid parts of blood.
What is interstitial fluid?
Extracellular interstitial fluid is the fluid between the cells.
What is transcellular fluid?
Transcellular fluid is found outside of the cells in cerebral fluid, lung fluid, …
What does hypotonic mean in reference to body fluids?
Hypotonic fluids will cause the fluids to move into a cell because the extracellular fluid has a lower osmolality than the cell.
What does hypertonic mean in reference to body fluids?
Hypertonic fluids will cause the fluids from the cell to move into the extracellular fluid, leaving the cell, because the osmolality in the extracellular fluid is higher than the cells osmolality.
What will occur as a result of hypotonic extracellular fluid?
The fluid will move through the cell membranes into the cell because the osmolality is higher in the cell which will cause the cell to swell.
What will occur as a result of hypertonic extracellular fluid?
The fluid in the cells will move through the cell membrane out of the cell into the extracellular fluid because the osmolality of the cell is lower than the extracellular fluid causing the cell to shrink/shrivel.
What does isotonic mean in reference to the body?
Isotonic solutions in the body means that the extracellular fluid is the same osmolality as the cell. Concentration of particles in all solutions are equal and so there is no movement between fluid compartments and the cells.
Isotonic - having equal osmotic pressure.
Is blood normally isotonic?
Yes, blood should normally be isotonic, meaning it is equal in tonicity to the body’s cells.
What does active transport mean in terms of electrolytes?
When fluids move across cell membranes, some need energy, ATP. Active Transport needs energy to move something against the concentration gradient, like pushing something up a hill. Active transport takes something from an area of less concentration to an area of greater concentration, in this case, electrolytes.
What is osmosis?
Osmosis is the passive movement of H2O across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration.
Is osmosis an active or passive process?
Osmosis is a passive process involving the movement of H2O specifically from lower to higher concentration..
What should be remembered about lab results reporting electrolytes?
Lab samples are blood samples so they are extracellular fluids, specifically, intravascular fluids, because of this, there will be larger quantities of electrolytes that reside in the extracellular fluids then those that reside within the cells.
Ex. Sodium - ECF - larger quantities in lab results, Potassium - ICF (Intracellular Fluid) - smaller quantities in lab results.
What are the 4 methods of fluid movement within the body?
The 4 methods of fluid movement within the body are:
- Active Transport
- Osmosis
- Diffusion
- Filtration
What is diffusion in terms of electrolytes?
Diffusion is a passive movement of electrolytes across cell membranes from an area of higher concentration to an area of lower concentration. Like rolling a ball down a hill. The particles are moving down the concentration gradient from an area of greater concentration to an area of lower particle concentration.
What serves as an ion channel for electrolytes? And when do electrolytes need them?
Electrolytes need proteins that serve as ion channels as they cross over the cell membrane.
What is an ion channel? What do they do?
Ion channels are specialized proteins in the plasma membrane that provide a passageway through which charged ions can cross the plasma membrane.
What is filtration in terms of fluids of the body?
Filtration is the net effect of 4 forces that move fluid/H2O into and out of capillaries between vascular and interstitial spaces.
What are the 4 components of filtration?
- Capillary hydrostatic pressure.
- Interstitial fluid hydrostatic pressure.
- Capillary colloid osmotic pressure (AKA oncotic pressure.
- Interstitial fluid colloid osmotic pressure.
What is Capillary hydrostatic pressure?
Capillary hydrostatic pressure is outward pushing force that helps move fluid from capillaries into the interstitial area.
What is interstitial fluid hydrostatic pressure?
Interstitial fluid hydrostatic pressure is an opposing pushing force to capillary hydrostatic pressure (stronger pushing force) that pushes fluid back into capillaries.
Which pushing force is stronger, Capillary hydrostatic pressure or Interstitial fluid hydrostatic pressure?
Capillary hydrostatic pressure is stronger than Interstitial fluid hydrostatic pressure.
What is colloid osmotic pressure (AKA oncotic pressure)?
Capillary colloid osmotic pressure (AKA oncotic pressure, is an inward pulling force caused by blood proteins that move fluid from interstitial area into capillaries.
What is interstitial fluid colloid osmotic pressure?
Interstitial fluid colloid osmotic pressure is inward pulling that moves fluid from capillaries into interstitial area.
What is another name for colloid osmotic pressure?
Another name for colloid osmotic pressure is oncotic pressure.
How is Capillary and interstitial filtration accomplished?
Capillary and interstitial filtration is accomplished via 2 hydrostatic pressures (pushing forces) and 2 colloid osmotic pressures (pulling forces).
When does filtration occur?
Filtration of body fluids is always taking place to keep the body’s fluids in a state of equilibrium and homeostasis. It is always trying to equalize the pressure between intracellular and interstitial space.
Can disease processes effect fluid filtration in the body?
Yes, disease processes can effect fluid filtration in the body by effecting the body’s ability to use the 4 types of filtration pressures (capillary hydrostatic, interstitial fluid hydrostatic, capillary colloid osmotic, and interstitial fluid colloid pressures) and preventing the body from maintaining equilibrium. Ex: edema, weak heart can change osmotic pressure and increase interstitial pressure fluid volume.
What is RAAS? What does it do?
RAAS is the Renin-Angiotensin Aldosterone System. The RAAS is controlled by cells in the kidney and controls the amount of H2O and NA+ lost in urine.
How many processes control fluid balance?
Fluid balance is controlled by 3 processes.
What are the 3 processes that control fluid balance?
Fluid balance in controlled by:
- Fluid intake and absorption (2300 mL per day).
- Fluid distribution - the movement of fluids to wherever needed.
- Fluid output via kidneys.
By what 3 fluid components do kidneys control fluid balance?
The kidneys control fluid balance in the body via:
- Antidiuretic hormone
- Renin-angiotensin-aldosterone system
- Atrial natriuretic peptide.
What does Antidiuretic hormone do?
Antidiuretic hormone is created in the hypothalamus and stored and released from the pituitary gland. ADH controls home much fluid we lose in our urine.
What does Atrial natriuretic peptide do?
Atrial natriuretic peptide is controlled by the atria in the heart. ANP controls H2O and Na+ loss in urine.
What are the main organ systems that effect fluid output?
The main organs systems that influence fluid output are: kidneys, skin, lungs, and G.I.
Who has the highest risk of dehydration?
Infants have the highest risk of dehydration because their bodies are 75% fluid.
What is the approximate daily absorption of fluid for an adult?
The daily absorption of fluid a day by an adult is approximately 2300mL.
What regulates fluid intake?
Thirst regulates fluid intake. 2300 mL/day is normal for an adult.
What body compartments comprise fluid distribution and balance in the body?
There are 4 different compartments that play a role in fluid distribution and they are:
- Extracellular Fluid (ECF)
- Intracellular Fluid (ICF)
- Vascular Fluid (VF)
- Interstitial Fluid (IF)
What hormones effect fluid balance?
Hormones that effect fluid balance are:
Antidiuretic hormone - ADH: Hypothalamus/Pituitary - fluid output
Renin-angiotensin-aldosterone system - RAAS: Kidneys - Na+ and fluid output
Atrial natriuretic peptides - ANP: Atria of the heart - Na+ and fluid output.
What are the 2 types of fluid loss?
The 2 types of fluid output are sensible and insensible loss.
What is sensible fluid loss?
Sensible fluid loss is easily measured as urine.
What is insensible fluid loss?
Insensible fluid loss is not easily measured. Ex. lungs, sweat, feces,…
What is an important regulator of fluid intake?
An important regulator of fluid intake is thirst.
How does thirst regulate fluid intake?
Thirst regulates fluid intake by urging us to drink. We get thirsty when there is a decrease in fluid and an increase osmolality in plasma.
Where is the thirst control mechanism located?
The thirst control mechanism is located within the hypothalamus in the brain.
Whose thirst response trigger is less sensitive?
An older person may have much less sensitivity to thirst and is thus a more likely candidate for dehydration.
How does the RAAS system work to maintain fluid balance in the body and prevent dehydration?
The renin-angiotensin-aldosterone system (RAAS) is kicked off when the kidneys detect a decrease in blood pressure. When decreased blood pressure is decreased, the kidneys release Renin with secretes Angiotensin 1 then 2. Angiotensin 2 causes the secretion of Aldosterone from the Adrenal Cortex. Sodium is reabsorbed in order to retain more H2O.
How does atrial natriuretic peptide (ANP) work to maintain fluid balance in the body and prevent dehydration?
The main purpose of atrial natriuretic peptide (ANP) is to lower blood pressure. Cardiac atria monitor atrial pressures for an increase thereby causing nephrons to increase sodium excretion. Sodium excretion occurs to decrease water retention.
How is atrial natriuretic peptide (ANP) triggered for release?
Atrial natriuretic peptide (ANP) is trigger by the stretching of the atria cardiac muscle. When cardiac pressure increases, the atria secrete the ANP hormone. ANP is a cardiac hormone that regulates Na+, H2O balance and blood pressure by promoting renal Na+ and H2O excretion and stimulating vasodilation.
What is the primary hormone responsible for tonicity and homeostasis in the body?
Antidiuretic Hormone (ADH) is the primary hormone responsible for tonicity and homeostasis.
What is tonicity, generally speaking?
Tonicity is the relative concentration of solutes dissolved in solution which determine the direction and extent of diffusion.
What electrolytes are more concentrated in the cells and bones than the extracellular spaces?
K+, Ca+, P+, and Mg, are all more concentrated within the cells and the bones than without.