Water, Electrolyte, and Acid-Base balance Flashcards
What term is another name for volume depletion? This occurs when proportionate amounts of both water and sodium are lost without replacement.
Hypovolemia
The excretion of what represents a major route of water loss?
Urine
Why is it important to maintain the pH of blood and tissue fluids within normal limits?
Slight deviations from normal pH can shut down metabolic pathways; the structure and function of macromolecules are pH dependent
What pH disorder is caused by hypoventilation and apnea?
Respiratory acidosis
Which pH disorder is caused by hyperventilation due to pain or emotions such as anxiety?
Respiratory alkalosis
What pH disorder can result from chronic vomiting; overuse of antacids; or aldosterone hypersecretion?
metabolic alkalosis
What pH disorder can result from excess production of organic acids, hyperkalemia, chronic diarrhea, excessive alcohol consumption, aspirin, and laxatives?
Metabolic Acidosis
List calcium, potassium, and phosphate imbalances from most dangerous to least dangerous
1: Potassium
2: Calcium
3: Phosphate
What are some important functions of sodium?
It is involved in generating body heat via the Na-K pump; It participates in cotransport of glucose, K+, and Ca+; it participates in muscle and nerve depolarization
What ion is the principle cation of the ECF?
Sodium
What is the condition called when there is a dangerously high plasma potassium concentration greater than 5.5 mEq/L?
hyperkalemia
What are two types of fluid deficiency?
hypovolemia and dehydration
What term refers to a compound that helps maintain stable pH by binding protons if H+ concentration begins to rise, and releasing them into solution if H+ concentration falls?
Chemical Buffer
What is the name for the condition when plasma concentration of potassium is less than 3.5 mEq/L?
hypokalemia
Which cation lends strength to the skeleton, activates muscle contraction, serves as a second messenger for some hormones and neurotransmitters, and is an essential factor in blood clotting?
calcium
What is the combination of water from food and drink known as?
preformed water
What are functions of potassium?
It helps produce the resting membrane potential and action potentials of nerve and muscle cells; it plays a role in cotransport and thermogensis via the Na+-K+ pump; it is an essential cofactor for protein synthesis and some other metabolic processes; it is the greatest determinant of intracellular osmolarity and cell volume
What is the loss of water through the breath and cutaneous transpiration?
insensible water loss
What is the loss of water through minimal urine formation; expired air; cutaneous transpiration; and fecal moisture?
Obligatory water loss
What is the loss of water through urine and visible sweating?
sensible water loss
List the routes of normal water loss from largest volume to smallest volume
1: Urine
2: Cutaneous transpiration
3: Expired Breath
4: Feces
5: Sweat
What hormones regulate sodium homeostasis?
Antidiuretic hormone; natriuretic hormone; aldosterone
When is a person in a state of fluid balance?
when daily fluid gains equal losses
What is the most abundant solute particle electrolyte in the ICF?
Potassium
What is the most abundant solute particle electrolyte in the ECF?
Sodium
Prolonged, heavy work increases water loss from what routes?
perspiration, respiratory loss
What occurs when blood volume and pressure are too high?
The release of ADH is inhibited
A tissue fluid pH below 7.35 is defined as a state of what?
acidosis
What mechanisms maintain intracellular calcium concentrations low?
Cells often have a protein called calsequestrin, which binds the stored Ca2+ and keeps it chemically unreactive; cells sequester Ca2+ in the smooth ER and release it only when needed; Cells actively pump out Ca2+
What happens to total body water and ECF with hypovolemia?
Total body water is reduced, ECF remains isotonic
What happens to total body water and ECF with dehydration?
Total body water is reduced and ECF becomes hypertonic
What happens to total body water and ECF with volume excess?
Total body water is elevated and ECF remains isotonic
What happens to total body water and ECF with hypotonic hydration?
Total body water is elevated and ECF becomes hypotonic
What is referred to as the “salt-retaining hormone” because it plays the primary role in adjusting sodium excretion?
Aldosterone
List the oder of events during neutralization of hydrogen ions in the kidney from the moment H2CO3 forms until HCO3- returns to blood, beginning with the formation of H2CO3 in the blood.
1: H+ in blood reacts with HCO3- to form H2CO3
2: H2CO3 decomposes into H2O and CO2, which enter the tubule cell
3: Tubule cells obtain CO2 from blood, and tubular fluid
4: CAH combines H2O and CO2 to re-form H2CO3
5: H2CO3 ionizes to form HCO3- (which returns to the blood to neutralize more H+ in the blood) and H+
What occurs when the body eliminates more water than sodium, so that the ECF osmolarity rises?
Dehydration
Why do cells maintain a very low intracellular calcium concentration?
calcium phosphate crystals would precipitate in the cytoplasm if levels were too high
What type of buffer system stabilizes pH by controlling the body’s output of acids, bases, or CO2? What are some examples?
Physiological buffer; respiratory and urinary system
Imbalances of which ion are the most dangerous of all electrolyte imbalances?
potassium
What is the condition in which plasma sodium concentration is less than 130 mEq/L?
hyponatremia
List the components of transcellular fluid
Vitreous and aqueous humors of the eye; cerebrospinal, synovial, peritoneal, pleural, and pericardial fluids; bile and fluid in the digestive, urinary, and respiratory tracts
List the four main fluid compartments of the body and the percentage of the body water they contain
1: Intracellular fluid: 65%
2: Tissue (interstitial) fluid: 25%
3: Blood plasma and lymph: 8%
4: Transcellular fluid: 2%
Water output is primarily controlled through variations in what?
urine volume
Approximately how much water is lost per day through urine?
1500mL
Approximately how much water is lost per day through feces?
200mL
Approximately how much water is lost per day through sweat?
100mL
Approximately how much water is lost per day through expired breath?
300mL
Approximately how much water is lost per day through cutaneous transpiration?
400mL
What would be considered a normal pH value for arterial blood?
7.4
What are the primary effects of aldosterone?
Urine contains less NaCl; Urine contains more K+; urine has a lower pH
What are the two types of fluid excesses?
volume excess and hypotonic hydration
What are functions of chloride ions?
They are important in osmotic balance; they play a mjor role in the regulation of body pH; they contribute to the formation of stomach acid; they participate in the chloride shift in that accompanies carbon dioxie loading and unloading
What occurs when the rate of alveolar ventilation fails to keep pace with the body’s rate of CO2 production?
carbon dioxide accumulates in the ECF and lowers it’s pH, causing respiratory acidosis
Aldosterone stimulates what?
renal secretion of potassium and renal reabsorption of sodium
Which ion acts as an important buffer that helps stabilize the pH of body fluids?
phosphate
What does aldosterone do to urine pH?
decreases pH
