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97 terms

ch24

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fluid compartments
Body water is distributed among certain _____,areas separated by selectively permeable membranes and differing from each in chemical composition
intracellular fluid
Where is the most of the body fluid located?
electrolytes, sodium, potassium
The most abundant solute particles by far are the _____, especially ___ in the ECF and ____ in the ICF
fluid balance
A person is a in a state of ____ when daily gains and losses are equal; normal distribution of fluids
metabolic water, preformed water
Routes of water gain are
metabolic water
is produced as a by-product dehydration synthesis reactions and aerobic respiration; water produced by the body's metabolism
preformed water
water gain through ingested food and drink
routes of water loss
1,500 ml/day in urine
200 ml/day in feces
300 ml/day in expired breath
100 mlday in sweat
400 ml/day in cutaneous transpiration
cutaneous transpiration
water lost through epidermis and then evaporated. Not the same thing as sweat, because it is not a glandular secretion
insensible water loss
Output through the breath and cutaneous transpiration is called _____, because we are not usually conscious of it
sensible water loss
Noticeable output, particularly through the urine and in case of sufficient sweating to produce obvious wetness of skin
obligatory water loss
output that is relatively unavoidable; expired air, cutaneous transpiration, sweat, fecal moisure, and the minimum urine output
thrist
fluid intake is governed mainly by _____
blood volume, blood pressure , blood osmolarity
Dehydration reduces ____ and ____, but raises ______
osmoreceptors
Fluid intake is governed mainly by _____< which monitor blood osmolarity and angiotensin level. When they sense a fluid deficity, they activate ADH secretion and the sense of thirst
volume, concentration, distribution
Body is in a state of fluid imbalance if there is an abnormality of total ___,____, or _____ of fluid among the compartments
volume depletion(hypovolemia)
occurs when water or sodium are lost without replacement. Total body water declines and osmolarity remains the same.
dehydration(negative water balance)
occurs when the body eliminates significantly more water than sodum so the ECF osmolarity rise.
-affects all fluid compartments
TBW reduced, osmolarity= hypertonic
angiotensin ii, antidiuretic hormone, hypothalamic osmoreceptors, inhibition of salivation
THirst center of anterior hypothalamus responds to
volume excess
both water and sodium are retained and the ECF remains isotonic.
TBW= elevated, osmolarity = isotonic
hypotonic hydration(positive water balance, water intoxication)
more water than sodium is retained or ingested and ECF becomes hypotonic
TBW= elevated, osmolarity=hypotonic
fluid sequestration
a condition in which excess fluid accumulates in a particular location. Most common form = edema
why electrolytes are important
chemically reactive
participate in metabolism
determine electrical potential across cell membranes
strongly affect osmolarity of body fluids and body's water content and distribution
aldosterone
promotes sodium and water retention, thus reduces urine output
antidiuretic hormone
promotes water reabsorption by CD , reduces water output
Natriuretic peptide
promtoes sodium and water loss
major cations
sodium , hydrogen, calcium , potassium are all ____ ___
major anions
chloride, bicabonate (HCO3-) and phosphates (Pi) are all ____ ____
sodium
principal cation in ECF; most significant solute in determining total body waater and distribution of water among fluid compartments
sodium bicarbonate(NaHCO3-)
____ plays a major role in buffering the pH of the ECF
aldosterone
plays the primary role in adjustment of sodium excretion
sodium
functions:
ECF osmolarity, TBW and water balance
resting and action potentials, excitability of neurons, muscles, heart
cotransport of glucose, K+ and other solutes
thermogenesis by Na+K+ pump
buffering of pH by sodium bicarbonate
sodium
homeostasis of this electrolyte is regulated by Aldosterone, ADH and NP
hypernatremia
causes: renal failure, improper IV thereapy, high salt diets
effects: H2O retention, hypertension and edema
hyponatremia
causes: usually hypotonic hydration
effects: disrupts neurological and cardiac function, can be lethal in hypotonic hydration
potassium
most abundant cation of the ICF and greatest determinant of intracellular osmolarity and cell volume is _____
potassium
principal determinant of ICF osmolarity and cell volume , resting and action potential , excitability of neurons muscles and heart. Cotransport, thermogenesis, cofactor for protein synthesis
aldosterone
Potassium homeostasis is regulated mainly by ____
hyperkalemia
causes: crush injuries, hemolytic anemia, bad transfusion, improper IV therapy, aldosterone deficiency, renal failure

effects: neuromuscular hyperexcitability, cardiac arrest, neuromuscular depression
slow onset
neuromuscular depression is an effect in ____ hyperkalemia
quick onset
cardiac arrest is an effect in ____ hyperkalemia
hypokalemia
causes: heavy sweating, chronic vomiting or diarrhea, aldosterone hypersecretion , alkalosis

effects: reduced excitability of neurons and muscles , weakness , poor muscle tone, depressed reflexes, cardiac arrhythmia
potassium
____ imbalances are the most dangerous of all electrolyte imbalances
chloride
most abundant anions of the ECF
regulation of water output
aldosterone, antidiuretic hormone, natriuretic hormone
7.35, 7.45
Blood and tissue fluid normally have a pH of ___-____
anaerobic fermentation
lactic acid comes from
nucleic acid catabolism
phosphoric acid comes from ________
fat catabolism
fatty acids and ketones both are results of _____
carbon dioxide
carbonic acid comes from _____
hydrogen ions
pH of solution is determined soley by its _______
acid
any chemical that releases H+ ina solution
strong acid
gives up most of its hydrogen ions and can markedly lower the pH of a solution
weak acid
keeps most hydrogen in a chemically bound form that does not affect pH.
base
any chemical that accepts H+
strong base
strong tendency to bind H+ and raise the pH
weak base
binds less of the available H+ and has less effect on pH
buffer
any mechanism that resists changes in pH by converting a strong acid or base to a weak one
physiological buffer
a system that stabilizes pH by controlling the body's output of acids, bases or CO2
urinary
____ system bufers the greatest quantity of acid or base, but its requires several hours to day to exert an effect
chemical buffer
substance that binds H+ and removes it from solution as its concetratio begins to rise, or releases H+ into solution as its concentration falls
can restore normal pH within a fraction of a second
buffer systems
mixtures of a weak acid and weak base
bicarbonate, phosphate, protein
3 major chemical buffer systems of the body are
bicarbonate buffer system
a solution of carbonic acid and bicarbonate ions
physiological buffer
pretains to ability of the lungs and kidneys to stabilize pH by controlling the body's output of acids, bases or CO2
chemical buffers
substances that stabilize pH by either binding or realeasing H+
phosphate buffer system
solution of HPO4(2-) and H2PO4-.
optimal pH for this system is 6.8
more important in renal tubules and icf
protein buffer system
accounts for 3/4 of all chemical buffering in body fluids
kidneys
neutralize more acid or base than the either respiratory system or the chemical buffers, because they actually expel H+ from the body
fluid deficiency
a ____ occurs when fluid output exceeds intake
fluid sequestration
a state in which total body water may be normal , but the water is maldistributed in body
chloride
important in osmotic balance, formation of stomach acid, and chloride shift mechanism in respiratory and renal function
chloride
is regulated as a side effect of sodium homeostasis
pH imbalance
primary effect of chloride imbalances is a ______
calcium
necessary for muscle contraction, neurotransmission , and other casess f exocytosis, blood clotting, some hormone actions and bone and tooth development
parathyroid hormone, calcitrol, calcitonin
Calcium homeostasis is regulated by ?
hypercalcemia
causes hyperparathyroidism, hypothyroidism, alkalosis
effects:neuromuscular depression , cardiac arrythmia
hypocalcemia
causes: hypoparathyroidism, hyperthyroidism, vitamin D deficiency, dirrahea, pregnancy , lacatation, acidosis

effects:neuromuscular hyperexcitability,muscle tetany, suffocation by laryngospasm
inorganic phosphate
_____ is necessary for the synthesis of nucleic acids and phospholipids, ATP, GTP, and cAMP; activates many metabolic pathyways by phosphorylating such substances as enzymes and glucose; and it is an important acid-base buffer
parathyroid hormone
phosphate levels are regulated by _____
urinary and respiratory system
2 examples of physiological buffer systems
kidneys
secrete H+ into the tubular fluid where it binds to chemical buffers and is voided from the body in the urine
respiratory acidosis
occurs when pulmonary gas exchange is insufficient to expel CO2 as fast as the body produces it
metabolic acidosis
is the result of lactic acid or ketone accumulation, excessive use of acidic drugs, such as aspirin or loss of base such as in cases of diarrhea
respiratory alkalosis
results form hyperventilation or high altitude; CO2 expired faster than it is produced
metabolic alkalosis
is rare but can be cause by overuse of antacids or loss of stomach acid through vomitting.
Uncompensated
_____acidosis or alkalosis is a pH imbalance that the body's homeostatic mechanisms cannot control on their own, it requires clinical intervention
compensated
_____acidosis or alkalosis is an imbalance that the body's homeostatic mechanism can correct
respiratory compensation
is correction of the pH through changes in pulmonary ventilation
renal compensation
is correction of pH by changes in H+ secretion by the kidneys
bicarbonate
Urine is usually ____ free, except if person is in state of alkalosis
acidosis, hypochloremia
Tubules secrete more NH3Cl to buffer the acid in the urine, leaving less Cl in the ECF
cause is ____ and potential effect is ____
acidosis, hypocalcemia
at low pH more ca2+ binds to plasma proteins and citrate ions, leaving less ca2+ free for metabolic uses
cause=_____ potential effect =_____
chemical buffers
buffer system reacts the quickest , but least effect of all systems
respiratory system
reaction time up to 3min, buffers less acid or base than urinary, but is more effective than chemical buffers
urinary system
reaction time is slowest , may take several hours to days, however they bufer greatest amount of acid or base
Aldosterone
promotes potassium excretion