Pathophysiology: Fluids and Electrolytes, Acids and Bases Flashcards

the sum of fluids within all body compartments; about 60% of body weight; expressed as a % of body weight in kilograms

comprises all the fluid within the cells; about 2/3 of TBW

all the fluid outside the cells and is divided into smaller compartments-interstitial fluid and intravascular fluid; other ECF compartments include: lymph and transcellular fluids-synovial, intestinal, and cerebrospinal fluid, sweat, urine, and pleural, peritoneal, pericardial, and intraocular fluids; about 1/3 of all TBW

the space between cells and outside the blood vessels

blood plasma

facilitates the outward movement of water from the capillary to the interstitial space

osmotically attracts water from the interstitial space back into the capillary

facilitates the inward movement of water from the interstitial space into the capillary

osmotically attracts water from the capillary into the interstitial space

movement of fluid back and forth across the capillary wall; best described as Starling's forces

net filtration=forces favoring-forces opposing filtration

forces favoring filtration=capillary hydrostatic pressure and interstitial oncotic pressure

forces opposing=capillary oncotic pressure and interstitial hydrostatic pressure

the excessive accumulation of fluid within the interstitial spaces; the forces favoring fluid movement from the capillaries or lymphatic channels into the tissues are increased capillary hydrostatic pressure, lowered plasma oncotic pressure, increased capillary membrane permeability, and lymphatic channel obstruction

occurs when lymphatic channels are blocked or surgically removed, proteins and fluid accumulate in the interstitial space

stimulated by increased osmolality causing thirst and the signaling of the pituitary to release ADH

nerve endings that are sensitive to changes in volume and pressure-stimulate the release of ADH from the pituitary gland; found in the aorta, pulmonary arteries, and carotid sinus

stimulate release of ADH from pituitary gland; located in the right and left atria and thoracic vessles

major anion in the ECF, and provides electroneutrality; particularly in relation to sodium; concentration tends to vary inversely with bicarbonate (HCO3-) the other major anion

a mineralocorticoid that is synthesized and secreted by the adrenal cortex and regulates sodium and potassium balance by altering reabsorption in the kidney

an enzym secreted by the juxtaglomerular cells of the kidney that is released in response to decreased blood pressure in the kidney and sympathetic nerve stimulation, and decreased blood volume

an inactive polypeptide; inactive product of the cleavage of angiotensinogen by renin

active hormone that is formed from the cleavage of angiotensin I by angiotensin-converting enzyme; stimulates aldosterone secretion and vasoconstriction

a mechanism by which sodium and water levels are regulated in the body, including the release of renin, conversion of angiotensinogen into angiotensin I, conversion of angiotensin II, and the release of aldosterone and its actions on the kidney that increase water and sodium reabsorption--increasing systemic blood pressure and restoring renal perfusion

promote urinary excretion of sodium and water and decreases blood pressure; 3rd factor in sodium regulation; after increased glomerular filtration rate and aldosterone (overcomes the sodium retaining action of aldosterone)--reduces blood pressure

a protein hormone that is synthesized and released from the atria in response to high sodium concentration, high extracellular fluid volume, or high blood volume; it promotes sodium secretion and causes vasodilation in the circulatory system

isotonic dehydration; causes contraction of the ECF volume with weight loss, dryness of skin and mucous membranes, decreased urine output, and symptoms of hypovolemia--rapid heart rate, flattened neck veins, and normal or decreased blood pressure

most commonly the result of excessive administration of intravenous fluids, hypersecretion of aldosterone, or the effects of drugs such as cortisone (which causes renal reabsorption of sodium and water); as plasma volume expands, hypervolemia develops with weight gain leading to decreased hematocrit and decreased plasma protein concentration; neck veins may be distended, blood pressure increases, edema

occurs when serum sodium levels exceed 147 mEq/L; may be caused by an acute gain in sodium or a net loss of water--intracellular dehydration; thirst, fever, dry mucous membranes, restlessness as a result of water loss; CNS: muscle twitching and hyperflexia; convulsions

predominantly extracellular cation

describes water deficit but also is commonly used to indicate both sodium loss and water loss (isotonic and isoosmolar dehydratioin)

hyperosmolar or hypertonic dehydration; thirst, dry skin and mucous membranes; elevated temperature, weight loss, and concentrated urine; skin turgor may be normal or decreased; hypvolemia: tachycardia, weak pulses, and postural hypotension

occurs clinically when there is too much sodium or too little bicarbonate; more than normal amounts of chloride can be expected with hypernatremia or metabolic acidosis

develops when serum sodium concentration fall below 135 mEq/L; sodium deficits usually cause hypoosmolality with movement of water into cells; sodium loss, inadequate sodium intake, or dilution of the body's sodium level by water excess; lethargy, confusion, apprehension, depressed reflexes, seizures, and coma,

caused by extrarenal losses, such as vomiting, diarrhea, gastrointestinal suctioning, and burns, or renal loss from the use of diuretics

occur when the proportion of TBW to total body sodium is excessive; weight gain, edema, ascites, and jugular vein distention

occurs when factors other than hyperosmolality or hypovolemia stimulate the secretion of ADH-caused by decreased renal excretion of water

caused by compulsive water drinking (psychogenic); acute renal failure, severe congestive heart failure and cirrhosis paired with IV infusion of 5% dextrose in water; decreased urine formation; confusion, convulsions, weakness, nausea, muscle twitching, headache, and weight gain

usually the result of hyponatremia or elevated bicarbonate concentration, as in metabolic alkalosis; develops with vomiting and loss of hydrochloric acid

major intracellular electrolyte and is essential for normal cellular functions; ECF concentration: 3.5-5.0 mEq/L; maintained by sodium-potassium adenosine triphosphate active transport system; required for glycogen and glucose deposition in liver and skeletal muscle cells, maintains the resting membrane potential; mainly regulated by the kidney

potassium deficiency; develops when serum potassium concentration falls below 3.5 mEq/L; neuromuscular excitability decreases, causing skeletal muscle weakness, smooth muscle atony, and cardiac dysrhythmias; amplitude of T wave decreases and amplitude of U wave increases, and ST segment is depressed; QRS complex can be prolonged in severe cases

elevation of ECF potassium above 5.5 mEq/L; mild: increased neuromuscular irritability-restlessness, intestinal cramping, and diarrhea; severe: muscle weakness, loss of muscle tone, and paralysis; decreased cardiac conduction and more rapid repolarization of heart muscle; narrow and taller T wave, and shortened QT interval

a substance such as carbonic acid (CO2 gas) that can evaporate rapidly--body acids

a substance that does not have a vapor form and can be eliminated by the kidney

the action of buffers minimizing the change in pH of a solution in response to the addition of acids or bases; most important plasma buffer systems are carbonic acid-bicarbonate and the protein hemoglobin; phosphate and protein are the most important intracellular buffers

a substance that can absorb excess acids or bases without causing a significant change in pH

adjustment of acid or base content by removal or addition in response to changes in pH; for example a decrease in pH is accompanied by an increase in carbon dioxide removal by the lungs, causing pH to increase

occurs when the values for both components of the buffer pair (carbonic acid and bicarbonate) return to normal levels

operates in both the lung and the kidney and is major extracellular buffer; the lungs decrease carbonic acid by blowing off carbon dioxide and leaving water, and the kidneys can reabsorb bicarbonate or regenerate new bicarbonate from carbon dioxide and water; 20:1 ratio maintained

the pH of arterial blood is less than 7.4

systemic increase in hydrogen ion concentration; an acid-base imbalance characterized by a reduction in arterial blood pH

the pH of arterial blood is greater than 7.4

a systemic decrease in hydrogen ion concentration; an acid base imbalance characterized by elevated pH

a decrease in pH caused by an increase in noncarbonic acids or a decrease in bicarbonate; headache, lethargy, anorexia, nausea, vomiting, diarrhea, and abdominal discomfort

an increase in pH caused by an increase in bicarbonate ions secondary to an increase in metabolic acid loss; weakness, muscle cramps, hyperactive reflexes, tetany, shallow and slow respirations, confusion, convulsions, and atrial tachycardida

a decrease in ventilation in relation to the metabolic production of carbon dioxide by an increase in carbonic acid; headache, blurred vision, apprehension, breathlessness, restlessness, lethargy, disorientation, muscle twitching, tremors, convulsions, and coma

occurs when there is alveolar hyperventilation and excessive reduction in plasma carbon dioxide levels (hypocapnia); dizziness, confusion, tingling of extremeties, convulsions and coma