Flashcards in Chapter 16 main points Deck (20)
• Body fluids and electrolytes play an important role in maintaining a stable internal environment of the body.
• A number of adaptive responses keep the composition and volume of body fluids and electrolytes within the narrow limits of normal to maintain homeostasis and promote health.
• Many diseases and their treatments have the ability to affect fluid and electrolyte balance and alter homeostasis.
WATER CONTENT OF BODY
• Water is the primary component of the body, accounting for about 60% of the body weight in the adult.
• The two major fluid compartments in the body are intracellular fluid (ICF), or inside the cells, and extracellular fluid (ECF), or outside the cells. ECF is composed of interstitial fluid, plasma, and transcellular fluids
• Electrolyte composition varies between the ECF and ICF, though the overall concentration of the electrolytes is nearly the same in the two compartments.
• The measurement of electrolytes is important in evaluating electrolyte balance, as well as in determining the composition of electrolyte preparations.
the amount of pressure required to stop the osmotic flow of water. Measuring osmolality is important because it indicates the water balance of the body
The tonicity of the fluid surrounding cells affects them.
1) Fluids with the same osmolality as the cell are?
2) Solutions in which the solutes are less concentrated than the cells are?
3) those with solutes more concentrated than cells or an increased osmolality are?
the force of fluid within a compartment and is the major force that pushes water out of the vascular system at the capillary level
osmotic pressure exerted by colloids in solution. The major colloids in the vascular system contributing to osmotic pressure are proteins, such as albumin
Oncotic pressure (colloidal osmotic pressure)
The amount and direction of fluid movement between the interstitium and the capillary is determined by the interaction of
(1) capillary hydrostatic pressure
(2) plasma oncotic pressure
(3) interstitial hydrostatic pressure
(4) interstitial oncotic pressure
When capillary or interstitial pressures are altered, fluid may abnormally shift from one compartment to another, resulting in?
edema or dehydration
• Fluid spacing describes the distribution of body water.
• First spacing describes the?
• Second spacing refers to an?
• Third spacing occurs when?
• First spacing describes the normal distribution of fluid in the ICF and ECF compartments.
• Second spacing refers to an abnormal accumulation of interstitial fluid (i.e., edema).
• Third spacing occurs when fluid accumulates in a portion of the body and it cannot be exchanged easily with the rest of the ECF (e.g., burns, blisters)
An intact thirst mechanism is important for fluid balance. The patient who cannot recognize or act on the sensation of thirst is at risk for?
fluid deficit and hyperosmolality
An increase in plasma osmolality or a decrease in circulating blood volume stimulates?
antidiuretic hormone (ADH) secretion
Glucocorticoids and mineralocorticoids secreted by the adrenal cortex help regulate?
- Aldosterone, a mineralocorticoid, has?
- Glucocorticoids and mineralocorticoids secreted by the adrenal cortex help regulate water and electrolytes.
- Aldosterone, a mineralocorticoid, has potent sodium-retaining and potassium-excreting capability
Insensible water loss
invisible vaporization from the lungs and skin, assists in regulating body temperature.
Fluid volume deficit can occur with?
abnormal loss of body fluids (e.g., diarrhea, drainage, hemorrhage, polyuria), inadequate intake, or a plasma-to-interstitial fluid shift.
Fluid volume excess may result from?
excessive intake of fluids, abnormal retention of fluids (e.g., heart failure, renal failure), or interstitial-to-plasma fluid shift
Hypernatremia, elevated serum sodium, may occur with inadequate water intake, water loss or, rarely, sodium gain.
♣ Symptoms include those of dehydration and any accompanying ECF volume deficit, such as?
♣ Hypernatremia is treated based on the cause.
♣ Symptoms include those of dehydration and any accompanying ECF volume deficit, such as postural hypotension, weakness, and tachycardia.
♣ Hypernatremia is treated based on the cause. With water deficits, volume is replaced. If sodium excess occurs, dilution is accomplished with sodium-free IV fluids.
Hyponatremia is a low serum sodium level. Common causes include a loss of sodium-containing fluids or water excess in relation to the amount of sodium.
♣ Symptoms of hyponatremia are related to?
♣ In hyponatremia from water excess, what is the treatment. If fluid loss is the cause?
♣ Symptoms of hyponatremia are related to cellular swelling and are primarily manifested in the central nervous system.
♣ In hyponatremia from water excess, fluid restriction is often the only treatment. If fluid loss is the cause, replacement with sodium-containing solutions is indicated.
Hyperkalemia is an elevated serum potassium level.
♣ The most common cause is?
Hyperkalemia is also common with?
♣ The most clinically significant manifestations of hyperkalemia are? Other manifestations include?
♣ The patient experiencing dangerous cardiac dysrhythmias should receive?
♣ The most common cause is renal failure. Hyperkalemia is also common with massive cell destruction (e.g., burn or crush injury, tumor lysis); metabolic acidosis; and catabolic states (e.g., severe infections).
♣ The most clinically significant manifestations of hyperkalemia are disturbances in cardiac conduction. Other manifestations include confusion, tetany, muscle cramps, and paresthesias, followed by weakness or paralysis of skeletal muscles. Monitor the ECG of all patients with hyperkalemia to detect potentially fatal dysrhythmias and monitor the effects of therapy.
♣ The patient experiencing dangerous cardiac dysrhythmias should receive IV calcium gluconate.