CH 5 Electrolytes
1. Total body water TBW is 60% of body weight
2. One liter of water weighs 2.2lb
3. Interstitial fluid the space between cells and outside blood vessels
4. Intravascular fluid is blood plasma
5. ECF 2/3
a. Sodium, chloride, potassium, calcium
b. Intravascular and interstitial
6. ICF 1/3
a. Phosphate, magnesium
7. Amount of TBW varies with body fat and age
a. Fat people have less fluid
b. Fat = hydrophobic = less water contained in fat = dehydration
8.Water movement
a. Osmolality is the concentration of fluid; measures amount of solute per kilogram
b. Osmolarity is the concreatrion of solute in milliosmoles per liter
c. Hydrostatic pressure pushes water; the pressure exerted by the fluid on the wall
of blood vessel
d. Osmotic pressure amount of hydrostatic pressure needed to stop the flow of
water by osmosis (depends on solute concentration)
e. oncotic pressure is the osmotic pressure exerted by proteins
f. oncotic pulls water
g. Water, sodium, and glucose can move across capillary membranes
h. Protein (albumin) do not cross capillary and maintain osmolality by generating
oncotic pressure
i. Filtration water moves out of capillary
j. Reabsorption water moves into capillary
k. Arterial end of capillary= hydrostatic pressure higher than oncotic which push
fluid out (filtration)
l. Venous end= oncotic higher than hydrostatic so it pulls fluid in (reabsorption)
m. Not all fluid gets reabsorbed some gets into the lymphatic system
n. 4 Forces
o. FILTRATION
i. Capillary hydrostatic pressure (BP) facilitates the outward movement of
water from capillary to interstitial space (like a hose)
ii. Interstitial oncotic pressure osmotically attracts water from the capillary
into interstitial space
p. REABSORPTION
i. Capillary oncotic pressure (plasma) osmotically attracts water from
interstitial space back to capillary
, ii. Interstitial hydrostatic pressure facilitates the inward movement of water
form the interstitial space into the capillaries
q.Water movement between ICF ECF
i. Osmotic forces move water
ii. Water moves by diffusion through lipid bilayer and aquaporins (water
channel proteins)
r. Edema
i. Excess fluid in the interstitial space
ii. Increase capillary hydrostatic pressure
1. Venous obstruction= higher bp to push fluid out
a. Tight clothing, standing, hepatic obstruction
2. Heart failure, renal failure retains fluid and salt
iii. Decrease capillary oncotic pressure
1. Liver injury
iv. Sodium water retention= Increased cap hydrostatic pressure
v. Decreased plasma albumin (cirrhosis or malnutrition) =Decreased plasma
oncotic pressure
vi. Increased cap membrane permeability
1. Inflammation
vii. Lymph obstruction
1. Removal of lymp
viii. Edema impairs blood flow so wound heal slow
ix. Fluid is trapped in the third space = dehydration or hypovolemia
9.Sodium chloride water imbalance
a. Antidiuretic hormone ADH retains water
b. Sodium
i. 90 % of ECF
ii. + charged
iii. Regulates water balance
iv. Transport
v. Conduction nerve impulse
vi. Regulates acid base balance
vii. Aldosterone retains sodium secrets from adrenal cortex
viii. R.A.A.S
ix. Triggered by
1. Decrease blood volume, bp, and sodium
2. Water follows sodium so it will increase everything
x. Decrease blood pressure or sodium= renin (enzyme) is secreted=
stimulates angiotensin I (inactive polypeptide)
, xi. Angiotensin converting enzyme ACE converts angio I to angiotensin ii=
stimulates aldosterone
xii. Aldosterone promotes renal sodium and water reabsorption and excretes
potassium = increase blood volume
xiii. Renin also cause vasoconstriction = increase bp
xiv. Natriuretic peptides opposite of raas stops aldosterone
1. Triggered by increase Na or too much drinking = increase plasma
volume = increase bp
2. Produced by myocardium
3. Atrial natriuretic hormone (ANH) produced by atria
4. B type nat hormone (BNP) produced by ventricles
5. Released when increase atrial pressure
6. Stops aldosterone synthesis
7. Vasodilator = Cause sodium water excretion= decrease bp
8. Decrease water sodium to decrease blood pressure
9. 1st factor is increased glomerular filtration rate
10. 2nd factor is aldosterone
11. 3rd is Natriuretic peptides
c. Chloride (Na follower)
i. Major Anion in ECF
ii. Maintains electroneutrality and balances out sodium
iii. Proportional to changes in Na. follower
iv. Inversely to bicarbonate
d. Water ADH
i. ADH retains water
ii. ADH release when
1. Increased plasma osmolality (osmoreceptors)
2. Decreased plasma volume (baroreceptors)
3. Decreased blood pressure (baroreceptors)
e. Increase plasma osmolality (increased Na or decrease water) stimulates
osmoreceptors in hypothalamus
1. As osmotic pressure increase
2. Sense changes in sodium concentration
3. As osmotic pressure increase= ADH increase (released from
posterior pit gland)
4. Cause thirst and release ADH
5. ADH increase water absorption = decrease plasma osmolality and
return it to normal urine concentration increase
6. Decrease urine output
f. Baroreceptors are released in decreased blood volume and drop in bp
1. Fluid loss (Vomit, dehydration, diarrhea, profuse sweating)
2. Stimulate sympathetic system
, 3. Decreased arterial pressure= baroreceptor transmit fewer
impulses= stimulate sympathetic= increase cardiac rate, release
adh= water sodium reabsorption
10. Alterations
a.Isotonic alteration
i. Most common
ii. Occur when equal loss or gain of TBW and electrolytes
iii. Hypovolemia
1. Isotonic fluid loss from ECF
2. Solutes concentration is same no change
3. No shift in fluid
4. Hypovolemia, dehydration, hemorrhage, wound drain
5. s/s
a. Decreased urine
b. Decrease bp
c. rapid hr
d. Flat neck vein
6. Give isotonic fluids
iv. Hypervolemia
1. Isotonic fluid excess
2. Hypervolemia (excess water and electrolytes)
a. Increase bp
b. Crackles in lungs
c. Excess administration of IV fluids
d. Hypersecretion of aldosterone
e. Neck vein distended
f. Too much fluid= spill in third space= Edema
g. Excess ADH
h. Give diuretics and refrain from sodium
b.Hypertonic alteration
i. ECF greater than 294 mOsm
ii. Osmolality of ECF is elevated causing water to leave cell
iii. Hypernatremia
1. salt exceed 145 mEq/L
2. Cause hypervolemia cuz water will move out of cell into the ECF
a. Bounding pulse, thirst, weight gain increase bp
3. Isovolemic hypernatremia (lose water)
a. Loss of free water with normal body Na concentration
b. Inadequate water intake, excess sweating, any type of fluid
loss,
1. Total body water TBW is 60% of body weight
2. One liter of water weighs 2.2lb
3. Interstitial fluid the space between cells and outside blood vessels
4. Intravascular fluid is blood plasma
5. ECF 2/3
a. Sodium, chloride, potassium, calcium
b. Intravascular and interstitial
6. ICF 1/3
a. Phosphate, magnesium
7. Amount of TBW varies with body fat and age
a. Fat people have less fluid
b. Fat = hydrophobic = less water contained in fat = dehydration
8.Water movement
a. Osmolality is the concentration of fluid; measures amount of solute per kilogram
b. Osmolarity is the concreatrion of solute in milliosmoles per liter
c. Hydrostatic pressure pushes water; the pressure exerted by the fluid on the wall
of blood vessel
d. Osmotic pressure amount of hydrostatic pressure needed to stop the flow of
water by osmosis (depends on solute concentration)
e. oncotic pressure is the osmotic pressure exerted by proteins
f. oncotic pulls water
g. Water, sodium, and glucose can move across capillary membranes
h. Protein (albumin) do not cross capillary and maintain osmolality by generating
oncotic pressure
i. Filtration water moves out of capillary
j. Reabsorption water moves into capillary
k. Arterial end of capillary= hydrostatic pressure higher than oncotic which push
fluid out (filtration)
l. Venous end= oncotic higher than hydrostatic so it pulls fluid in (reabsorption)
m. Not all fluid gets reabsorbed some gets into the lymphatic system
n. 4 Forces
o. FILTRATION
i. Capillary hydrostatic pressure (BP) facilitates the outward movement of
water from capillary to interstitial space (like a hose)
ii. Interstitial oncotic pressure osmotically attracts water from the capillary
into interstitial space
p. REABSORPTION
i. Capillary oncotic pressure (plasma) osmotically attracts water from
interstitial space back to capillary
, ii. Interstitial hydrostatic pressure facilitates the inward movement of water
form the interstitial space into the capillaries
q.Water movement between ICF ECF
i. Osmotic forces move water
ii. Water moves by diffusion through lipid bilayer and aquaporins (water
channel proteins)
r. Edema
i. Excess fluid in the interstitial space
ii. Increase capillary hydrostatic pressure
1. Venous obstruction= higher bp to push fluid out
a. Tight clothing, standing, hepatic obstruction
2. Heart failure, renal failure retains fluid and salt
iii. Decrease capillary oncotic pressure
1. Liver injury
iv. Sodium water retention= Increased cap hydrostatic pressure
v. Decreased plasma albumin (cirrhosis or malnutrition) =Decreased plasma
oncotic pressure
vi. Increased cap membrane permeability
1. Inflammation
vii. Lymph obstruction
1. Removal of lymp
viii. Edema impairs blood flow so wound heal slow
ix. Fluid is trapped in the third space = dehydration or hypovolemia
9.Sodium chloride water imbalance
a. Antidiuretic hormone ADH retains water
b. Sodium
i. 90 % of ECF
ii. + charged
iii. Regulates water balance
iv. Transport
v. Conduction nerve impulse
vi. Regulates acid base balance
vii. Aldosterone retains sodium secrets from adrenal cortex
viii. R.A.A.S
ix. Triggered by
1. Decrease blood volume, bp, and sodium
2. Water follows sodium so it will increase everything
x. Decrease blood pressure or sodium= renin (enzyme) is secreted=
stimulates angiotensin I (inactive polypeptide)
, xi. Angiotensin converting enzyme ACE converts angio I to angiotensin ii=
stimulates aldosterone
xii. Aldosterone promotes renal sodium and water reabsorption and excretes
potassium = increase blood volume
xiii. Renin also cause vasoconstriction = increase bp
xiv. Natriuretic peptides opposite of raas stops aldosterone
1. Triggered by increase Na or too much drinking = increase plasma
volume = increase bp
2. Produced by myocardium
3. Atrial natriuretic hormone (ANH) produced by atria
4. B type nat hormone (BNP) produced by ventricles
5. Released when increase atrial pressure
6. Stops aldosterone synthesis
7. Vasodilator = Cause sodium water excretion= decrease bp
8. Decrease water sodium to decrease blood pressure
9. 1st factor is increased glomerular filtration rate
10. 2nd factor is aldosterone
11. 3rd is Natriuretic peptides
c. Chloride (Na follower)
i. Major Anion in ECF
ii. Maintains electroneutrality and balances out sodium
iii. Proportional to changes in Na. follower
iv. Inversely to bicarbonate
d. Water ADH
i. ADH retains water
ii. ADH release when
1. Increased plasma osmolality (osmoreceptors)
2. Decreased plasma volume (baroreceptors)
3. Decreased blood pressure (baroreceptors)
e. Increase plasma osmolality (increased Na or decrease water) stimulates
osmoreceptors in hypothalamus
1. As osmotic pressure increase
2. Sense changes in sodium concentration
3. As osmotic pressure increase= ADH increase (released from
posterior pit gland)
4. Cause thirst and release ADH
5. ADH increase water absorption = decrease plasma osmolality and
return it to normal urine concentration increase
6. Decrease urine output
f. Baroreceptors are released in decreased blood volume and drop in bp
1. Fluid loss (Vomit, dehydration, diarrhea, profuse sweating)
2. Stimulate sympathetic system
, 3. Decreased arterial pressure= baroreceptor transmit fewer
impulses= stimulate sympathetic= increase cardiac rate, release
adh= water sodium reabsorption
10. Alterations
a.Isotonic alteration
i. Most common
ii. Occur when equal loss or gain of TBW and electrolytes
iii. Hypovolemia
1. Isotonic fluid loss from ECF
2. Solutes concentration is same no change
3. No shift in fluid
4. Hypovolemia, dehydration, hemorrhage, wound drain
5. s/s
a. Decreased urine
b. Decrease bp
c. rapid hr
d. Flat neck vein
6. Give isotonic fluids
iv. Hypervolemia
1. Isotonic fluid excess
2. Hypervolemia (excess water and electrolytes)
a. Increase bp
b. Crackles in lungs
c. Excess administration of IV fluids
d. Hypersecretion of aldosterone
e. Neck vein distended
f. Too much fluid= spill in third space= Edema
g. Excess ADH
h. Give diuretics and refrain from sodium
b.Hypertonic alteration
i. ECF greater than 294 mOsm
ii. Osmolality of ECF is elevated causing water to leave cell
iii. Hypernatremia
1. salt exceed 145 mEq/L
2. Cause hypervolemia cuz water will move out of cell into the ECF
a. Bounding pulse, thirst, weight gain increase bp
3. Isovolemic hypernatremia (lose water)
a. Loss of free water with normal body Na concentration
b. Inadequate water intake, excess sweating, any type of fluid
loss,
