fluid and electrolytes Flashcards
about 2/3 of the total body water is in the ___ while the remaining 1/3 is in ___
- 2/3 is in intracellular fluid
- 1/3 is in the extracellular fluid
extracellular fluid consists of
interstitial fluid and lymph (15% body weight), plasma (3% body weight), and the transcellular fluids, which include GI fluid, urine, and CSF.
the main cation in the intracellular fluid (ICF) is __, but the main cation in extracellular fluid (ECF) is __
- ICF: K+
- ECF: Na+
The presence of a widened anion gap signifies the presence of a _______
metabolic acidosis due to a nonchloride containing acid.
Persistently low anion gaps are a serious sign of _________
possible malignancy, i.e., myeloma
what two acids do not have Cl- as their counter-ion so may contribute to a larger anion gap?
acetoacetic acid and lactic acid
which clinical condition is associated with a large anion gap do to the presence of acetoacetic acid?
diabetic acidosis
Total osmolality or osmotic pressure of a
solution is equal to the sum of the
____
osmotic pressures or osmolalities of all
solutes present
who contributes more to the osmolality of serum, proteins or electrolytes?
electrolytes by far
what is the osmolal gap best used to detect
However, the osmolal gap is most effectively used to detect and follow poisonings with nonelectrolytes such as acetone, ethanol, methanol, ethylene glycol, and some others
osmolal gap values up to 10 (moderate increases) are associated with \_\_\_\_\_\_
-ketoacidosis, renal acidosis, and lactic
acidosis
In the venous part of capillaries, oncotic pressure _____ hydrostatic pressure, and fluid is drawn into the ____
- prevails over hydrostatic pressure
- vascular lumen
Why would we see edema in a condition like Kwashiokor?
Inadequate protein in diet leads to insufficient synthesis of albumin. A reduction in plasma oncotic pressure, which occurs, for instance, as a consequence of a decrease in the plasma albumin concentration, results in the movement of fluid into the extravascular space and in edema.
What is the major function of kidneys?
Kidneys maintain the composition, osmolality, and volume of the ECF and also control the acid-base balance
The kidneys produce _____ involved in calcium
homeostasis, and ______which
controls the production of erythrocytes
-calcitriol (1α,25-dihydroxycholecalciferol,
1,25(OH)2D3)
-erythropoietin
where does plasma filtration occur?
at the glomeruli in the kidney
where is sodium reabsorbed in the nephron?
-More than 80% of filtered sodium is
actively reabsorbed in the proximal tubule
-sodium is also reabsorbed in the ascending loop of Henle
-also at distal convoluted tubule but…A different mechanism
operates in the distal tubule, where
sodium reabsorption is stimulated by
aldosterone and is coupled with the
secretion of hydrogen and potassium ions.
In clinical practice, __ and ___
are first-line tests in the diagnosis of renal
failure.
serum urea and creatinine
The most common cause of
severe hyperkalemia is ___.
renal failure: in this condition
potassium cannot be adequately excreted in the urine
how are electrolytes determined?
ion-specific electrodes (ISE’s)
what is plasma?
liquid, cell free part that has been treated with anticoagulants
serum
liquid part of blood that has been collected after coagulation
where is angiotensin-II synthesized??
the blood
Renin is synthesized by juxtaglomerular cells of the kidney and ultimately leads to production of ___
angiotensin II
what does angiotensin II do?
kidneys: increase Na+ retention, H2O retention
Brain: corticotropin and adiuretin (thirst)
adrenals: Aldosterone production
blood vessels: vasoconstriction
Aldosterone regulates __ and ___ homeostasis
K+ and Na+
what is commonly found in hypertension
hyperaldosteronism
when is renin secreted??
sodium levels decline or there is a fall in blood
pressure.
when would you use an ACE inhibitor?
to treat hypertension or CHF
elevated levels of Atrial natriuretic peptide (ANP) are found during ___ states
hypervolemic states and CHF
BNP and NTpro-BNP are sensitive, diagnostic markers for ____ in patients.
heart failure
_____ determines the final volume and
concentration of the urine
Vasopressin
vasopressin
Vasopressin is synthesized in the
hypothalamus and is transported along axons to the
posterior pituitary where it is stored before being
further processed and released. It binds to a receptor
located on the membranes of tubular cells in the
collecting ducts. The receptor is coupled to G-proteins
and activates protein kinase A (PKA). PKA
phosphorylates aquaporin 2 (AQP2), which stimulates its
translocation to the cell membrane, increasing water
reabsorption in the collecting duct.
Vasopressin deficiency causes the condition known as ______
diabetes insipidus
inappropriate antidiuretic hormone secretion (SIADH)
an excessive secretion of vasopressin may occur
following major trauma or surgery. This is known as the syndrome of inappropriate antidiuretic hormone secretion (SIADH), and leads to water retention.
