SODIUM AND POTASSIUM Flashcards
are essential components of all living matter
Electrolytes
Include major electrolytes:
Na+, K+, Ca+2, Mg+2, Cl-, HCO3-,
HPO4-2, SO4-2, Proteins, Lactate, Trace metals
The major electrolytes occur primarily as (?) whose properties are unaffected by other ions or molecules.
free ions
The trace metals occur primarily in combination with
proteins
- Maintenance of osmotic pressure & water distribution in the various body fluid compartments (?)
Na+, K+, Cl-
- Maintenance of the proper pH/acid-base balance (?)
HCO3- , K+, Cl-
- Regulation of the proper function of the heart and other muscles (?)
K+, Ca+2, Mg+2
- Involved in
oxidation-reduction reactions or electron transfer reaction
- Participation in catalysis as cofactors for enzymes (?)
Mg+2, Ca+2, Zn+2
- Some electrolytes are even involved in
blood coagulation
is the major cation of ECF
Sodium
It represents about 90% of extracellular cations
Sodium
plays a central role in maintaining the normal H2O distribution and the osmolality of plasma.
Sodium
Na Reference range:
136 – 145 mmol/L
Sodium can be excreted in urine when the renal serum threshold
of sodium exceeds
110–130 mmol/L
This is the major intracellular cation
Potassium
Only 2% is found in the plasma
K
is 20x greater inside of the cell
K conc
Tissue cells (?)
average of 150mmol/L
RBC (?)
105 mmo/L
Sodium is initially filtered by the
glomeruli
About (?)of sodium filtered is reabsorbed in the proximal convoluted tubules along with bicarbonate and water.
60 to 70%
About (?) is reabsorbed in the loop of Henle with chloride and more water.
25-30%
While reabsorption in the distal convoluted tubules is controlled
by (?), a hormone that conserves sodium.
aldosterone
“Coupled System with the Sodium-Potassium Sodium-Hydrogen Exchange”
Sodium
Like sodium, (?) is also the most important organ in the regulation and handling of potassium.
kidney
Potassium once filtered by the glomerulus if almost completely reabsorbed in the (?).
proximal convoluted tubules
Under the influence of aldosterone, potassium is secreted in the (?) hence the distal nephron is the principal determinant of urinary potassium excretion.
distal tubules and collecting duct
The renal threshold of sodium is between (?)
110–130 mmol/L
are the ultimate regulators of the amount of Na+ or K+ in the body
kidneys
The following are the normal value for sodium:
o Serum/Plasma :
o Urine (24 hr) :(varies w/ diet)
o CSF :
136 – 145 mmol/L
40 – 220 mmol/L
136 – 150 mmol/L
The following are the normal value for K:
Serum of adults:
Plasma:
Newborn:
CSF:
Urine: (varies w/ dietary intake)
3.5 – 5.0 mmol/L
3.5 – 4.5 mmol/L
3.7 – 5.9 mmol/L
~70% of values in serum
25 – 125 mmol/L
IMPORTANCE OF WATER
(?) for all processes
Transport (?) to the cells
Determines (?)
Removes (?) (by way of urine)
Serves as a (?) (by way of sweating/perspiration)
(?)
(?)
Solvent
nutrients
cell volume
waste products
coolant
Active Transport
Diffusion
Accounts for 2/3 of total body water
INTRACELLULAR FLUID
aka PLASMA
Intravascular ECF
Normal Plasma
93%
Remaining are
H2O
lipids and proteins
Fluid that surround the cells in tissues
Interstitial fluid
Requires energy from atp
Active Transport
Maintenance of electrolyte balance
Active Transport
Passive movement of ion across membrane
Diffusion
Size, and charge of ions
Diffusion
SODIUM
intake of H2O (polydipsia)
plasma osmolality
Arginine vasopressin (AVP/ADH) (thirst are suppressed)
↑
↓
↓
in the absence of (?), water is not reabsorbed causing large volume of
diluted urine to be excreted
AVP
