Fluid, Electrolyte 52 Flashcards
Intercellular fluid
Within body cells
2/3 of body fluid in adults
Extra cellular fluid
Outside of cells
1/3 of body fluid
Two main compartments of extra cellular fluid ECF
Intravascular and interstitial
Intravascular fluid
Plasma
20% of ECF
Interstitial fluid
75% ECF
Surrounds cells
Other compartments of ECF
Lymph and transcellular fluids
Transcellular fluid
Cerebrospinal, pericardial, pancreatic, intraocular, biliary, peritoneal, synovial fluids
Electrolytes
Capable of conducting electricity
Example: Na+ and Cl-
Cations
Positive charge
Anions
Negative charge
Milliequivalent
Refers to the chemical combining power of the ion
Or
Capacity of cations to combine with anions to form molecules
Laboratory tests usually use…
Plasma. This reflects what is happening in ECF, especially intravascular fluid
ICF cations and anions
Cations: potassium and magnesium
Anions: phosphate, sulfate
Selectively permeable
Water moves easily through, but other substances vary.
Solutes
Substances dissolved in a liquid
Crystalloids
Salts that dissolve readily into true solutions
Colloids
Substances like large proteins that do not readily dissolve into true solutions
Solvent
Component of a solution that can dissolve a solute
Body solvent
Water
Body solutes
Electrolytes, gases, urea, amino acids, proteins
Osmolality
Concentrations of solutes in body fluids
Water is vital for normal cellular function
Medium for metabolic reactions Transporter for nutrients and wastes Lubricant Insulates, shocks Body temperature
Isotonic
Same osmolality as ECF
Hypertonic
Higher osmolality than ECF
Hypotonic
Lower osmolality thanECF
Osmotic pressure
Power of a solution to pull water across a semipermeable membrane
Colloid osmotic pressure or inciting pressure
Plasma proteins exert osmotic pressure. Hold water in plasma and in their vascular compartment
Diffusion
Two solutes of different concentrations are separated by a semipermeable membrane
Osmosis
Water moves across cell membranes from area of less concentration to area of more concentration (of solutes)
Filtration
Fluid and solutes move across a membrane from an area of higher pressure to lower pressure
Example of filtration
Fluid and nutrients from capillaries to interstitial fluid
Filtration pressure
Pressure that results in movement of fluid and solutes out of a compartment
Hydrostatic pressure
Pressure exerted by a fluid within a closed system on the walls of the container in which it is contained
Blood on vessel walls
Active transport
Movement of solutes across cell membrane from a less concentrated area to a more concentrated one
Active transport important to
Sodium snd potassium ion concentration of ECF and ICF
Thirst center of brain
Hypothalamus
Angiostensin ( reduced blood flow to kidneys)
Normal urine output
1400 to 1500 mL daily
Feces
Amount of chyme enters intestine. 1500 mL daily
100 ml reabsorbed
Insensible losses
Through skin and lungs
300-400 mL daily
Obligatory losses
Fluid losses required to maintain body function
500 ml through kidneys
1300 ml total daily
Kidneys
Primary regular of body fluids and electrolyte balance
ADH
Regulates water excretion from kidneys
Renin- angiotensin - aldosterone system
Neuroendocrine system helps maintain fluid balance
Atrial natriuretic factor
Atrium of heart, responds to stretching and excess fluid volume
Atrial natriuretic factor on thirst
Inhibits thirst, reducing fluid intake
Electrolytes are important for
Maintaining fluid balance
Acid-base regulation
Enzyme reactions
Transmit neuromuscular reactions
Sodium
Most abundant cation in EFC. Controls serum osmolality
Normal sodium levels
135- 145 mEq/ L