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Homeostasis
- State of balance
- causes of alteration environment, personal behaviors, infection, disease
- ongoing process
- essential to life
- when the body loses the ability to maintain homeostasis and the internal enviornment changes, the physiologic processes can be interupted or changed, leading to disease, disorder, or death
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Elements
- made of tiny units called atoms
- four elements (oxygen, carbon, hydrogen, nitrogen) constitute more than 95% of the total body weight of the elements
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Atoms
- smallest unit of chemical structure
- no chemical change can ulter it
- protons+, neutrons, electrons-
- the number of protons and neutrons in the nucleus is approximately equal to the atomic weight
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Isotopes
- atoms of the same element that have a different atomic weight
- some are radioactive isotopes- have an unstable nucleus
- alpha- least harmful
- gamma- most harmful
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Molecules
- atoms of the same element join together
- H + H -> H2
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Compounds
- atoms of 2 or more different elements join together
- Na + Cl -> NaCl
- inorganic- without carbon
- organic- with carbon
- 2H + O -> H2O
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Ions
- compounds placed in water decompose
- an atom bearing an electrical charge
- cation+, anion-
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Processes
- Synthesis
- decomposition
- solute
- solvent
- electrolyte solution
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Water
- constitutes 60% of total body weight in adult
- 70-80% infants, 45-55% older adult
- Functions- solvent, transporter, regulate body temp, lubricate, componant of all cells, hydrolysis
- balance regulated by hypothalmus
- involved in many of the physical and physiological processes
- major component of blood
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Gases
- 2 important in body oxygen and carbon dioxide
- oxygen needed by the cells to carry out functions
- when its used leaves body as carbon dioxide
- breathing is stimulated by high CO2 levels
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Acids
- anyhting that gives up hydrogen
- yeild hydrogen ions with a positive charge
- important hydrochloric acid and carbonic acid
- all other body fluids contained in the cells
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Bases
- accepts H+ to form a bond
- contains no hydrogen bond
- Sodium bicarbonate
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Salts
- acid and base react with each other
- many of the compounds that dissociate into ions in living cells are salts
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pH
- 7 neutral
- greater then 7- base or alkaline
- less then 7- acid
- pH is of great biological importance
- human body ranges from 7.35 to 7.45
- below 7.35 acidosis (death usually occurs first)
- above 7.45 alkalosis (S/S hightened state of nervous system activity, resulting in spasmodic muscle contractions, convulsions, and even death)
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Buffers
- substances that try to maintain the pH
- bicarbonate buffer system, phosphate buffer system, protein buffer system
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Bicarbonate Buffer System
- found in both the intracellular and extracellular fluids
- body's primary buffer system
- attemps to maintain bodys pH
- 2 components carbonic acid and sodium bicarbonate
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Phosphate Buffer System
regulate the pH of intracellular fluid and the fluid of the kidney tubules.
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Protein Buffer System
- found inside the cells
- maintain pH inside the cell mostly RBC
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Substance Movement
- Passive- diffusion(particles from are of greater concentration to an area of less concentration), osmosis(movement of water until equal always attracted to higher concentration), filtration(movement of substances against cell membrane)
- Active- carrier molecule moves substances into cells
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Isotonic Solutions
0.9% NS, Lactated Ringers
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Hypotonic Solutions
- 0.45% NS (1/2 NS)
- 0.33% NS
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Hypertonic Solutions
- 5% Dextrose & 0.45% NS (D51/2 NS)
- 5% Dextrose & LR (D5LR)
- 3-5% NaCl
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Body Fluid Compsrtments of Adults
- 65% intracellular
- 35% extracellular (9% intervascular, 26% interstitial)
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Fluid & Electrolyte Balance
- human life is suspended in a saline solution having a salt concentration of 0.9%
- for life to continue and cells to properly function, fluids must remain fairly conctant
- electrolytes make up 90-95% of bodies solution molecules
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Fluid Balance/Imbalance (Dehydration)
- Water moves out of the cells
- causes- water deprivation, sweating, excess urination, hemorrhage, diuretics, diarrhea, laxatives abuse, vomiting burns
- Hormones- ADH, Aldosterone, Renin
- Regulators of Fluid Balance- hydrostatic and Osmotic pressure
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Edema
- occurs in interstitial space
- causes- kidney disease, liver disease, heart disorder
- weight gain is a sign
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Sodium
- Location- Extracellular
- Function- regulates fluid balance through osmotic pressure that results from water following sodium, stimulates conduction of nerve impulses, help maintain neuromuscular activity
- Source- dietary
- Excreted- kidney
- Normal values- 135-145mEq/L
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Hyponatremia
- decreased Na
- Causes- decreased Na intake, prolonged vomiting, diarrhea, gastric or intestinal suctioning
- Complications- edema, hypotension, rapid thready pulse, weakness, seizures, abd cramping
- Data Collection-
- Interventions- limit fluids, IV, I&O, daily weight, safety
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Hypernatremia
- increased Na
- causes- DI, cushings, decreased water intake, corticosteroid use,
- data collection- neuro changes, low grade fever, flushed dry skin, dry mucus membranes
- Interventions- low Na 2g/day, increase fruits and vegi, no salt subs, vitals, I&O, increase water
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Sodium foods
table salt, soy sauce, cottage cheese, america cheese, mustard, ketchup, chicken, beef lean
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Potassium
- Location- intracellular
- Functions- nerve impulses and muscle function- heart
- Source- dietary
- Excreted- kidney
- normal values- 3.5-5mEq/L
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Hypokalemia
- 2.5 critical
- causes- decreased intake,
- Data collection- muscle weakness, leg cramps, hypotension, cardiac arrhythmias
- Interventions- vitals, I&O, neuro strength , safety, oriented frequently, bed low, alarm, check every 30 mins, peak P flat T
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Hyperkalemia
- 6.5 fatal
- causes- meds, metabolic acidosis, celluar destruction, adrenal insuf, intake, kidney failure, excretion
- Data Collection- muscle weakness, oliguria, anuria, respiratory distress, decreased cardiac contractility, EKG changes, reflexes
- Interventions- may need insulin, diuretics, kayexalate, decrease K intake
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Kayexalate (Sodium polystyrene sulfonate)
- Potassium removing resin
- releases Na in exchange for K
- PO, Enema
- SE- constipation, anorexia, low levels of K, Ca, Mg
- Interventions- monitor bowel function, electrolyte levels
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Calcium
- Location- 99% bones and teeth, 1% blood
- Function- bone and teeth integrity, blood clotting, smooth & skeletal muscle, nerve impulse
- Value- 9-10.5mq/dL (8.6-10 nclex)
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