Fluid & Electrolytes Flashcards
Total body water (as a percent of body mass) _____ from birth to old age.
declines
_____ is ~ 65% water by weight, while _____ is only ~ 20% water by weight: the relative proportion of these tissues controls the proportion of the body that is composed of water.
Muscle; adipose tissue OR fat
In a relatively lean individual, about 2/3 of their body water is _____, and roughly 1/3 is _____.
intracellular; extracellular
Extracellular fluid consists of fluid in two compartments: _____ and _____.
interstitial fluid; blood plasma
_____ fluid is a broad term which is usually taken to include CSF, serous fluid, lymph, etc.
Interstitial
Substances which are dissolved in the body’s fluid are divided into two classes: _____, which ionize, and _____, which do not ionize. Ions, of course, are able to _____.
electrolytes; non-electrolytes; conduct an electric current
Because it dissociates into two particles in solution, a mole of NaCl contributes more to _____ than a mole of glucose. Such dissociation is common to many electrolytes and must be considered when calculating the _____.
osmotic pressure; tonicity of a solution
When ions are dissolved in solution, their concentration is often measured in _____, which is a measure of the number of _____ per _____. (NOTE: be able to convert from moles per liter to this unit if given the charge of an ion.)
milliequivalents; charges; liter
The major cation in extracellular fluid is _____, and the major anions are _____ and _____.
sodium; chloride; bicarbonate
The only cation in the extracellular fluid which makes an important contribution to osmotic pressure is _____.
sodium
Under the conditions normally found in the body, most proteins have a net _____ charge and so are _____ .
negative; anions
The major cation in intracellular fluid is _____, and the major anions are _____ and _____.
potassium; hydrogen phosphate; negatively charged proteins
The volume of intracellular fluid is determined in large part by the osmolarity of the _____, which is in turn determined primarily by the _____ content of the body.
extracellular fluid (ECF); sodium
Water loss which is unavoidable (due to evaporation from the lungs during breathing, etc.) is _____ water loss.
insensible
_____ water loss accounts for about 1/3 of the daily water loss (and water lost must, of course, be replaced).
Insensible
Water lost in _____ and _____ accounts for roughly 1/10 of the daily water loss (which needs to be replaced).
feces; sweat
Water lost in _____ accounts for almost 2/3 of the daily water loss (which needs to be replaced).
urine
Changes in _____ is the primary trigger for release of ADH and for the sensation of thirst.
plasma osmolarity
_____ in plasma osmolarity inhibit the release of ADH and prevent the sensation of thirst.
Declines
The primary sensors for hydration which control conservation of water or the sensation of thirst are the _____ in the _____.
osmoreceptors; hypothalamus
The secondary sensors for hydration which sense changes in the body’s hydration severe enough to cause changes in blood volume, are the _____ cells in each _____.
juxtaglomerular OR JG; kidney
It takes so long for liquid to be absorbed from the stomach that drinking until plasma osmolarity is correct would result in _____. For this reason, thirst must be quenched in response to sensations from the _____ and _____.
over-hydration; mouth; stomach
Consumption of water leads to abrupt declines in thirst to prevent over-hydration as liquid is consumed, but when insensible loss or sweating is unusually severe, this may lead to a(n) _____.
inadequate fluid intake
_____ and _____ can cause dysregulation of the thirst response and lead to an inadequate intake of water.
Illness; old age
Because urine can only be concentrated to a certain point, the minimal daily water loss through urine in an average adult is approximately _____.
500 ml
The insensible water loss and the minimal daily water loss through urine are together called the _____ water loss. Drinking at least this amount is necessary on a daily basis.
obligatory
Water stored with glycogen inside of cells enters the ECF when _____; in addition, water is a product of _____. However, most water must be obtained by ingestion.
the glycogen is used for energy; oxidative phosphorylation;
If insufficient water is consumed, the result is _____. Many of the consequences are due to the fact that the cells themselves lose _____. Common causes are _____ or _____.
dehydration; water; vomiting; diarrhea
The earliest sign of dehydration is often simply _____, followed in healthy individuals by _____, _____ and decreased _____.
fatigue; dry mouth, thirst, urine output
ADH is released when the hypothalamus senses a(n) _____.
slight increase in plasma osmolarity
In order to respond to sudden events such as blood loss, signals from sensors in the _____ respond to low blood pressure by triggering the release of ADH. Such signals are also sent if the drop in blood pressure is due to _____.
blood vessels; severe dehydration
When ADH levels are _____, filtered water is reabsorbed, resulting in a lower volume of concentrated urine.
high
Over-hydration may dilute the ECF enough that osmotic pressure will force water to enter cells; _____ cells are the most sensitive. _____ is possible and disorientation, convulsions, and death may result.
neuronal; Cerebral edema
Over-hydration is generally caused by _____ or _____.
renal insufficiency; extremely rapid fluid intake
Edema is the accumulation of fluid in _____, which may impair tissue function.
the interstitial space
Factors that may cause _____ include inflammation, osmotic imbalances, high blood pressure, and impaired lymphatic function.
edema
The level of sodium in the blood is described with the word, ‘_____.’
natremia
If the sodium content of the body changes, so does the _____. Thus, the concentration of sodium _____.
water content; does not change
The hormone _____ controls sodium resorption, and a deficiency in this hormone leads to a severe sodium loss.
aldosterone
Since aldosterone secretion is controlled by angiotensin II, which is in turn controlled by renin, aldosterone release is indirectly controlled by the _____ cells, which produce the renin.
juxtaglomerular OR JG
Aldosterone secretion is also controlled by the _____ level in the blood, which is sensed directly by the _____.
potassium; adrenal cortex
The heart produces _____ in response to high blood pressure. This hormone reduces blood pressure and blood volume by inhibiting release of ADH, renin, and aldosterone, and by directly causing vasodilation.
atrial natriuretic peptide (ANP)
The female sex hormone _____ also promotes sodium resorption and thus water retention. In contrast, the female sex hormone _____ has the opposite effect.
estrogen; progesterone
High levels of glucocorticoids enhance sodium _____, but often have little net effect on sodium retention because they also increase _____, which accelerates sodium excretion.
resorption; glomerular filtration
rate
The level of potassium in the blood is described with the word, ‘_____.’
kalemia
Any change in extracellular ion concentrations which _____ the difference in potential across the membrane of an excitable cell makes it more likely that the cell will depolarize, and more difficult to repolarize.
decreases
Any change in extracellular ion concentrations which _____ the difference in potential across the membrane of an excitable cell makes it less likely that the cell will depolarize, and easier to repolarize.
increases
One of the dangers if blood pH falls too low is that as positive hydrogen ions enter the cells, _____ may leave to maintain electrical neutrality, resulting in an increase in _____.
K+; extracellular potassium
In contrast to sodium, for which levels in the body are controlled by the amount _____, levels of potassium are controlled by the amount _____.
resorbed; secreted
In general, we consume _____ potassium, and the main function of the kidneys is to _____ potassium. In contrast, we are poorly equipped to deal with a(n) _____.
too much; eliminate excess;
deficiency
Secretion of potassium is controlled by two factors: one is by its _____, which is sensed by the _____ in the _____.
concentration in the IF; principal cells; collecting duct
Secretion of potassium is controlled by two factors: one is by the hormone _____, which is released by the _____ when the level of potassium in the blood is high. This hormone causes potassium to be exchanged with sodium in the urine.
aldosterone; adrenal glands OR adrenal cortex
The level of calcium in the blood is described with the word, ‘_____.’
calcemia
The major reservoir for calcium in the body is the _____.
skeleton
The most important mineral in bone is the insoluble _____.
calcium phosphate
As renal resorption of _____ increases, resorption of hydrogen phosphate (HPO 2-) 4 decreases in order to avoid formation of an insoluble precipitate in blood and tissue or in urine.
calcium
The most important hormonal control of calcium homeostasis is _____ hormone, which is released by the _____ in response to _____ calcium levels.
parathyroid; parathyroid glands; low
In the kidneys, parathyroid hormone leads to calcium _____ in the _____, which depends on the calcium-ATPase pump.
resorption or reabsorption; DCT
In the small intestine, parathyroid hormone causes an increase in calcium absorption due to the _____ by the _____.
activation of vitamin D; kidneys
In the skeleton, parathyroid hormone causes _____ to _____ bone and release calcium into the blood.
osteoclasts; dissolve
A minor influence on calcium concentration in blood is the hormone _____, which is released by the _____ and which encourages bone formation.
calcitonin; thyroid
The amount of chloride in the blood is described by the word _____.
chloremia
_____ is the major anion in the ECF, and is a contributor to the osmotic pressure of the blood.
Chloride
An upper limit to the concentrations of most anions in the blood is provided by the _____: excess levels cannot be resorbed and are lost in the urine.
carrying capacity of the transport proteins in the nephrons
Chloride and bicarbonate both have a(n) _____ charge. Chloride is usually resorbed in the DCT of the kidneys, but if the body needs to resorb more bicarbonate to maintain blood pH, the kidneys _____ in order to _____.
negative; resorb less chloride; maintain electrical neutrality
