FLUID COMPARTMENTS AND FLUID BALANCE Flashcards
In lean adults, body fluids make up between
55 - 60% of total body mass.
Fluids are present in two main “compartments” –
inside cells and outside cells.
About two-thirds of body fluid is
intracellular fluid (ICF) or cytosol, the fluid within cells.
The other third, called extracellular fluid (ECF), is outside cells and includes all other body fluids.
About 80% of the ECF
is interstitial fluid, which occupies the spaces between tissue cells,
and about 20% of the ECF is blood plasma.
Two “barriers” separate intracellular fluid, interstitial fluid, & plasma:
- plasma membrane and
- blood vessel walls
Body Fluid Compartments image
slide 6
means that the various body compartments contain the normal amount of water and solutes.
Fluid balance
Water is the largest single component in the body, is about how much of the total body mass?
45%-50%of total body mass.
Daily water gain and loss are each about
2.5 L/day.
Sources of water gain are ingested liquids, (food and drinks) and water produced by
metabolic reactions.
Water is lost from the body through
urine, evaporation from the skin surface, exhalation by the lungs, and
GI tract (feces, defecation)
An area in the hypothalamus of the brain known as
the thirst center governs the urge to drink.
When water loss is greater than water gain, known as ?
dehydration, a decrease in volume and an increase in osmotic pressure of body fluids—stimulates thirst.
reduces urinary loss of Na+ and Cl– and water, thereby increases the volume of body fluids.
- Aldosterone
(Control of water levels)
promotes natriuresis, elevated excretion of Na+ (and Cl–) and water, which decreases blood volume and blood pressure
- Atrial natriuretic peptide (ANP)
(Control of water levels)
The major hormone that regulates water loss is
Antidiuretic hormone (ADH), also called vasopressin.
An increase in the osmotic pressure of body fluids stimulates ADH, which triggers the kidneys to
to reabsorb water. (RAA System) kicks in when blood pressure drops
Pathways through which Dehydration Stimulates Thirst:Renin - ADH image
Slide 12-13
Summary of Factors that Maintain Body Water Balance
Slide 14
The ions formed when electrolytes break apart serve four general functions in the body:
- Control the movement (osmosis) of water between fluid compartments.
2.Help maintain acid–base balance. (ph)
- Carry electrical current.
- Serve as cofactors for optimal activity of enyzmes.
(Electrolytes in Body Fluids)
are the most abundant extracellular cations.
Sodium ions (Na+)
involved in action potentials, muscle contraction, and fluid and electrolyte balance
(ECF IONS)
Na+ level is controlled by:
chlorine ions (Cl–) are the major extracellular anions.
They play a role in regulating osmotic pressure and forming HCl in gastric juice.
ECF IONS
Cl– level is controlled by processes that
increase or decrease kidney reabsorption of Na+.
ECF IONS
are the most abundant cations in intracellular fluid.
Potassium ions (K+)
Potassium ions (K+) play a key role in?
establishing the resting membrane potential in neurons and muscle fibers, and contribute to regulation of pH.
ICF IONS
K+ level is controlled by
aldosterone.
the most abundant mineral in the body.
Calcium
Ca2+, which are principally extracellular cations function in?
blood clotting, neurotransmitter release, and contraction of muscle.
is controlled mainly by PTH hormone and Calcitonin
ICF IONS
Sodium NA+ has a high content in the
ECF
Key anion that is high in the ECF is
is chloride Cl-
Key cation high concentration in the ICF
potassium K+
Blood Electrolyte Imbalances chart
Slide 21-22
Na+
aka Hyponatremia
Deficiency
may be due to decreased sodium intake; increased sodium loss through votiming, diarrhea, aldosterone deficiency, or taking certain diuretics; and excessive water intake.
Hyponoatremia (NA+)
Deficiency signs and symptoms
Muscular weakness; dizziness, headache, and hypotension; tachycardia and shock; mental confusion, stuptor, and coma
Hyponoatremia (NA+) EXCESS causes:
Signs/symptoms
(EXCESS)
may occur with dehydration, water deprivation, or excessive sodium in diet.
Intense thirst, hypertension, edema, agitation, and convulsions
Chloride:
aka Hypochloremia
(Deficiency)
Signs/symptoms
Due to excessive vommiting, overhydration, aldosterone deficiency, congestive heart failure, and therapy with certain diuretics such as fureemide (Lasix)
Hypochloremia (Cl-) DEFICIENCY signs/symptoms
Hypochloremia (Cl-) causes:
DEFICIENCY
Muscle spasms, metabolic alkalosis, shallow respirations, hypotension, and tetany
Hypochloremia (Cl-) causes:
EXCESS
Signs/Symptoms:
result from dehydration due to water loss, or water deprivation; excessive chloride intake; or severe renal failure, certain types of acidosis and some drugs
Signs: lethargy, weakness, metabolic acidosis, and rapid, deep breathing
Potassium (K+) aka Hypokalemia
DEFICIENCY
Results from
a lower than normal potassium level in your bloodstream.
excessive loss due to vomitting or diarrhea, decreased potassium intake, hyperaldosternonism kidney disease, and some therapy with some diuretics.
Potassium (K+) aka Hypokalemia signs and symptoms
(Deficiency)
Muscle fatigue, mental confusion, increased urine output, shallow respirations, flattening of T-wave
Potassium (K+) aka Hypokalemia
EXCESS signs and symptoms
Due to excessive potassium intake, renal failure, aldosterone deficiency, crushing injuries to body tissues.
Causes: Irritability, nausea, vomiting, diarrhea, muscular weakness; can cause death
Calcium (Ca2+)
aka
Hypoalcemia
DEFICIENCY
Signs/Symptoms
Hypocalcemia deficiency due to increased calcium loss, reduced calcium intake, elevated phosphate levels.
Signs/Symptoms:
Numbness and tingling of giners, muscle cramps, tetany, bone fractures, spasms.
Ca2+ aka Hyperalcemia
EXCESS
Signs/Symptoms
Hyperalcemia condition in which the calcium level in the blood becomes too high.
Signs/Symptoms:
Lethargy, weakness, anorexia, nausea, vomiting, itching, bone pain, depression
ACIDOSIS is a systemic arterial blood pH
below 7.35; it causes depression of the central nervous system
ALKALOSIS is a systemic arterial blood pH
above 7.45; its principal effect is overexcitability of the CNS.
The normal pH range of systemic arterial is
blood is 7.35 to 7.45_.
Homeostasis of pH is maintained by;
- Buffers
- Kidney
- Lungs
Acid-base balance
A buffer is
is a solution that helps to RESIST changes in pH when acid or base (alkali) levels change in a solution.
Three Buffer Systems Acting in the Body:
-Protein buffer system (hemoglobin)
-Carbonic Acid- bicarbonate buffer system
-Phosphate buffer system
______ Breathing plays an important role in maintaining the pH of body fluids.
Exhalation of carbon dioxide
An increase in the carbon dioxide in body fluids increases or decreases H+
increases H+ concentration and thus decreases the pH (more acidic).
The slowest but BEST mechanism for removal of acids is also the only way to eliminate most acids that form in the body.
Kidney excretion of H+
Cells of the renal tubules secrete ?
secrete H+, which then is excreted in urine.
Negative Feedback loop of Blood pH by the Respiratory System Image
Slide 29
Buffer Systems do what?
Convert strong acids and bases into weak acids and bases, preventing drastic changes in body fluid PH
Proteins are?
The most abundant buffers in body cells and blood. Hemoglobin is a buffer in blood plasma
Carbonic acid-bicarbonate are?
Important regulators of blood pH; most abundant buffers in intracellular fluid and urine
Exhalation of CO2 is?
Increased exhalation of CO2 pH rises (fewer H+); with decreased exhalation of CO2; pH falls (more H+)
Kidneys do?
Kidney tubules secrete H+ into urine and reabsorb HCO3- so that it is not lost in urin
With increasing age, there is?
there is DECREASED intracellular fluid volume and DECREASED potassium due to declining skeletal muscle mass.
Decreased kidney function does?
adversely affects fluid and electrolyte balance, (and pH).
Decreased lung function can?
can affect pH balance.
