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28 Cards in this Set
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ICF
INTRACELLULAR FLUID |
Intracellular fluid is critical for maintaining cell size and function.
Primary ICF electrolytes: potassium, phosphate, and sulfate. |
Infant: more ECF than ICF
3mo: ICF= EFT Adult: 2/3 ICF and 1/3 ECF |
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ECF
EXTRACELLULAR FLUID |
Extracellular fluid is compromised of all the fluids outside of the cell. ECF Includes intravascular fluid, the fluid inside the blood and lymphatic vessels, and interstitial fluid, the fluid between the cells.
Primary ECF electrolytes: sodium, chloride, and bicarbonate. |
Maintenance of the proportional distribution of ECF between vascular and interstitial paces depends on three factors:
1. Protein content in blood - serum proteins, mainly albumin and globulin. 2. Integrity of the vascular endothelium - the layer of cells lining blood vessels. 3. Hydrostatic pressure inside the blood vessels. |
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ECF:
INTERSTITIAL FLUID |
Interstitial fluid, which surrounds the body's cells, is important for transportation of oxygen, nutrients, hormones, and other essential chemicals between the blood and cell cytoplasm.
*Vascular and interstitial fluids also are important for waste removal. |
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ECF:
VASCULAR FLUID |
Vascular fluid is essential for the maintenance of adequate blood volume, blood pressure, and cardiovascular functioning.
*Vascular and interstitial fluids also are important for waste removal. |
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BODY FLUID ACCORDING TO AGE AND SEX
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Premature Newborn: 85%
Full-term Newborn: 70%-80% Child (1-12): 64% Puberty-39Yr: Male 60% Female 52% 40-60Yr: Male 55% Female 47% 60yr+: Male 52% Female 46% |
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RENIN
an enzyme secreted by juxtaglomerular cells in the kidney, splints angiotensionogen, produced by the liver and circulating in the blood, into angiotensin I. |
Converting enzymes in the lungs and other vascular bed convert angiotensin I into angiotensin II, a potent vasoconstrictor.
Angiotensin II stimulates secretion of aldosterone. |
Aldosterone, prduces by the adrenal cortex, regulates sodium reabsorption in the distal tubules and collecting ducts of the kidney.
Chloride and water passively accompany the reabsorbed sodium, resulting in the reabsorption of saline, a 0.9% solution of sodium chloride, which is ECF. |
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ANP
Atrial natriuretic peptides are produces by the cardiac atria, ventricles, and other body parts in response to changes in the ECF volume. |
WHen atrial pressure is increased, ANP released by the atrial and ventricular myocytes acts on the nephron to increase sodium excretion.
Low atrial pressure inhibit release of ANP. |
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OSMOLARITY
refers to the proportion of dissolved particles (solute) in a volume of fluid. (mOsm/L) milliosmols per liter. |
Hypothalamic osmoreceptor cells monitor changes in the body fluid osmolarity and respond by varying the secretion of anitdiuretic hormones (ADH) from the posterior pituitary.
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OSMOLALITY
refers to the concentration of dissolved substances in a given weight of fluid (ex: a kilogram), rather than in a given volume. (mOsm/kg) milliosmols per liter. |
Osmolarity/ Osmolality
because body fluids are very dilute, these terms are often used interchangeably. NORMAL OSMOLARITY RANGE 280-300 mOsm/L Sodium, it's accompanying anions, and glucose are the predominant osmotically active particles in the ECF. |
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ADH
antidiuretic hormone produced in the supraoptic and paraventricular nuclei of the hypothalamus. From nuclei, ADH passes down axons in the posterior lobe to the pituitary, where it is stored. |
When plasma osmolarity increases and activates the hypothalamic osmoreceptos, ADH is released into the systemic circulation.
ADH maintains the blood's osmolarity within normal limits by adjusting the amount of water excreted in the urine. |
The hormone acts by causing pore-like molecules called aqueporins to be inseted into the lumil membranes of the distal tubules and collecting tubules in the kidney, thus making them more permeable to water.
When ADH is increased, the urine becomes more concentrated. *When vascular volume is normal, changes in plasma osmolarity control ADH release. However, when atrial blood pressure is markedly diminished, ADH is released regardless of plasma osmolarity in response to input from the vascular baroreceptors. |
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ELECTROLYTES
are chemical compounds that partially dissociate (separate) in solution into separate particles. Each particle carries an electrical charge are known as ions. positive + cations negative - anions |
ECF electrolytes
sodium (Na+), Chloride (Cl-), bicarbonate (HCO3-) ICF electrolytes potassium (K+), phosphate (HPO-4 and H2PO4-), sulfate (SO4-) others... calcium (Ca++), magnesium (Mg++) |
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milliequivalent-
the measure of chemical activity: combining power, or the ability of cations to combine with anions. It is the amount of electrolyte in a solution is most commonly expressed in terms of milliequivelents per liter (mEq/L) concentration of electrolytes cannot be measured clinically, changes in serum level reflect body electrolyte imbalance. |
CATIONS
Sodium (Na+) 135-145 mEq/L Potassium (K+) 3.5-5.0 mEq/L Calcium (Ca++) 4.3-5.3 mEq/L Magnesium (Mg++) 1.5-1.9 mEq/L ANIONS Chloride (Cl-) 95-108 mEq/L Bicarbonate (HCO3-) 22-26 mEq/L Phosphate (HPO4-, H2PO4-) 1.7-2.6 mEq/L |
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SODIUM (Na+)
Normal: 135-145 mEq/L Most abundant cation in ECF. Changes in serum levels reflects changes in body water balance and osmolarity. Regulated along with chloride and normal saline, by the renin-angiotensin-aldosterone system and natriuretic peptides. |
SODIUM FOUND IN...
table salt (sodium chloride), dairy products, meat, eggs, and certain vegetables. Food processing add salt and some medications contain significant amounts of sodium. |
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POTASSIUM (K+)
Normal: 3.5-5.0 mEq/L Essential for normal cardiac, neural, and muscle function and contractility of muscles. Important roll in cellular functions, such as protein and glycogen synthesis. Two hormones exert major control over the ECF concentration of potassium: Insulin and aldosterone. |
Insulin, a pancreatic hormone, promotes the transfer of potassium (and also glucose) from ECF into skeletal muscle and liver cells.
Aldosterone, enhances renal excretion of potassium. *An increase in serum potassium stimulates the release of insulin and aldosterone to lower the concentration of the ion. Regulation of potassium in the kidneys. |
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CALCIUM (Ca++)
Normal: 8.9-10.1 mg/dL Present in the blood primarily in two states: ionized and bound to protein. Important i wound healing, synaptic transmission in nervous tissue, membrane excitability, muscle contractility, and teeth and bone structure. Essential for blood clotting and crucial in metabolic reactions involved with energy production (glycolysis). |
Ionized calcium determines the physiologic function, and only changes in the ionized calcium levels can cause the signs and symptoms associated with calcium imbalances. Regular is 4.0-4.9 mg/L. Determine if calcium replacement is needed via ionized calcium.
Larger proportion of calcium is bound to albumin, the serum albumin levels should be checked when laboratory data are evaluated. |
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Calcium is...
Regulated by parathyroid hormone (PTH), vitamin D, and to some extent calcitonin regulate calcium and phosphate balance. PTH causes sserum calcium levels to increase by increasing intestinal and renal reabsorption of calcium and releasing calcium from bone. Calcium usually has a reciprocal relationship with phosphorus. If PTH increases calcium level, it decreases phosphate levels, and vice versa. |
CALCIUM FOUND IN...
Dairy products: milk, cheese, yogurt, etc. Sardines, whole grains, and leafy green vegetables. |
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MAGNESIUM (Mg++)
Normal: 1.4-1.75 50-60% is located in bone, the rest is in soft tissues and body fluids. Magnesium is primarily an intracellular ion, and only 2% is in ECF. Important for regulation neuromuscular function and cardiac activity. Alterations in magnesium are often parallel with changes in potassium. |
Kidney regulates magnesium levels by reabsorbing the ion when serum levels are low and excreting it when serum levels are high. No hormones are linked to it's regulation.
Found in... green leafy vegetables, legumes, citrus fruit, peanut butter, and chocolate. |
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PHOPHORUS
Normal: 2.5-4.0 mg/dL Dibasic (HPO4-) and monobasic (H2PO4-) 85% bone, 14% ICF, 0.1% ECF Important in energy metabolism, structure of bones and membranes, and synthesis of nucleic acids (RNA/DNA) |
Phosphorus is controlled by regulation of renal excretion under the influence of vitamin D and PTH.
Sources... dairy products, meats, vegetables, fruits, and cereals. |
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DIFFUSION
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Diffusion is the movement of a solvent of solutes (molecules) from an area of higher solvent or solute concentration to an area of lower solvent or solute concentration.
Important in regulation electrical neutrality: a stat in which numbers of anions and cations are balanced within each fluid compartment, is the normal condition within compartments. |
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OSMOSIS
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Osmosis refers to the movement of a fluid through a semipermeable membrane.
Greater concentration of a dissolved substance (hyperosmolar) than the other compartment (hypoosmolar). Net effect is to equalize solution concentrations on both sides of the membrane. Remember: Water always moves to an area of greater concentration of dissolved particles. |
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ACTIVE
TRANSPORTATION |
Active transportation is the process by which ions and other molecules are moved across membranes from an are of lesser concentration to an area of greater concentration. Energy is required.
EX: Sodium-Potassium Pump. |
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FILTRATION PRESSURE
OSMOTIC PRESSURE HYDROSTATIC PRESSURE |
Filtration involves the transfer of water and dissolved substances through a permeable membrane from a region of high pressure to a region of low pressure.
Hydrostatic pressure, or the pressure exerted by fluid against the walls of it's container, promotes the flow of fluid out of the capillaries. Ex: kidney's glomerular capillaries and blood capillaries. Osmotic pressure, the force of attraction for water by undissolved particles. |
THUS, Hydrostatic pressure minus osmotic pressure equals the filtration pressure.
Ex: The hydrostatic pressure of the blood is about 32 mmHg, and the osmotic pressure is approximately 22 mmHg. The filtration pressure would them be +10 mmHg. Ex2: If the hydrostatic pressure is greatly increased or the osmotic pressure is greatly reduced, some of the filtered fluid remains in the interstitial space. This accumulation is known as edema. |
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TONICITY
Solutions are also categorized in relation to their tonicity, a term that refers to the fluid's effect on cell size. |
Hypotonic solution: concentration of solute that is less than that of blood plasma.
Hypertonic solution: the effective concentration of solute is greater than that of the blood plasma. *Tonicity of solution affects of fast water will jump into the cells floating in that solution- shrink or swell! |
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ACID-BASE
BALANCE |
cell require oxygen, nutrients, electrolytes, and a controlled temperature in their environment.
HOWEVER another important component of the cellular environment is the hydrogen ion concentration ([H+]) which is regulated within extremely narrow limits. This maintenance is the acid-base balance. |
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CARBONIC ACID
most important acid in the body |
When carbon dioxide enters the blood, it combines chemically with water to form carbonic acid (H2CO3-).
This weak, unstable acid partially dissociates to H+ and HCO3 (bicarbonate) ions. |
carbonic acid and bicarbonate ion form what is known as a buffer pair. This bicarbonate-carbonic acid buffer system is most important in clinical practice for two reasons:
1. all the buffer systems are in equilibrium, changes in the bicarbonate-carbonic acid system mirror changes in all other systems. 2. THe body regulates the carbon dioxide level by changes in the respiratory rate (ventilation) and bicarbonate level by adjustments in the amount of bicarbonate lost in the urine of the amount regenerated in the kidneys. |
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BUFFERS
are substances that help to prevent large changes in pH by absorbing or releasing H+ ions. Buffers allow acids or bases to be transported from where they are produced to where they are excreted without causing a large swing in PH |
Four Main Buffers
hemoglobin (HHgb and Hgb), carbonic acid-bicarconate, proteins (HPr and Pr), and phosphates (H2PO4- and HPO4-) |
ISOHYDRIC PRINCIPLE
if the clinician knows what is happening with one buffer pair, then they can predict what is happening with the others. |
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COMPENSATION
the body either excretes or retains acids or bases to compensate for losses. Acid-Base balance is commonly evaluated by arterial blood gases. |
RESPIRATORY COMPENSATION
lungs handle moment-to-moment maintenace of acid-base status because they react almost instantly to minute changes in blood pH. carbon dioxide maintained at PaCO2 at pressure of 36-44 mmHg. |
RENAL COMPENSATION
kidneys are slower than lungs to react to changes, taking hours to days to respond. They either increase excretion of H+ ions into the urine, or return HCO3- ions to the blood. Kidneys may take hours to 2 days to respond, thus slow. |
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INTAKE
Oral fluids 1300mL Fluid in Food 1000mL Oxidation of food 300 ml TOT: 2600mL/24hrs |
OUTPUT
Urine 1500mL Feces 200mL Perspiration 100-200mL Insensible loss *Skin 300-400mL *Respiratory 300mL TOT 2400-2600mL |
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