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Salt and Water

Sodium and Water Physiology
  • Body fluid compartments

Water distribution across cell membrane

TODO: osmolarita & volny prechod vody cez aquaporiny
Zjednodusene: Osm_ECF = Osm_ICF
Komplexne: Vyrovnanie chemickeho potencialu vody
Experiment: bunka v cistej vode resp. v izotonickom roztoku 
Kanalkove zmeny osmolarity: NKCC-1, Na+/H+ exchanger, Cl-shift

Water distribution across capilary membrane

TODO: hydrostaticky+osmoticky tlak
Komplexne: Vyrovnanie chemickeho potencialu vody and Gibbs-Donnan equilibrium
Experiment: zmena koncentrace albuminu v plazme/zmena pH v plazme
plasma proteins .. 0.8 mmol/L
change of albumin charge dependent of pH
  • Physiology of sodium

Long-term sodium study

TODO: 105-510 days of fixed Na+ intake -> Na intake and outtake equilibrium after 1 month, but remained in Na+ balance without change in body weight 
non-osmotic Na+ storage: in the skin or in the skeletal muscle; highly sulfated, negatively charged glycosaminoglycans 
typical wester diet: 150mmol/day
normal ECF = low Na diet (Paleolithic times)! 

Carotid sinus stimulation decrease kidney Na reabsorption

 ANP + Neural regulation

Efective arterial blood volume - ECF - Na+ content correlation

 Typically: Na loading -> EABV expansion; Na loss -> EABV depletion
 Heart failure: EABV depletion -> decrease baroreceptor pressures -> kidney Na retention -> increase ECF (peripheral/pulmonary edema) but low EABV

Kidney Na+ excretion

 GFR = 180 L/day, PNa = 150 mmol/L, Na reabsorption .. 27000 mmol/day, Na excretion .. 150 mmol/day, lot of energy/O2 used

Kidney EPO release

 dependent od PO2 (renal O2 delivery and O2 consumption to Na+ reabsorption)

Juxtamedullary nephrone(15% of all nephrones) Na+ reabsorption


 Na-K-ATPase .. driving force (basolateral membrane - dalej od tubulu)
 specific transporter (cotransporters/antiporters) .. (luminal membrane - v tubule)
 Proximal tubule .. Na+ a cenne latky (e.g. glucose, AA, HCO3-)  .. 66% z GFR

Inulin micropuncture study

inulin is not secreted nor reabsorbed in tubules
micropuncture inulin concentration in different nephrone part

Superficial nephrone(85% of all nephrones) Na+ reabsorption

LH do not descent into inner medula
  • Physiology of water
  • Integrative physiology


Potassium Physiology

Integrative Physiology


body weight 70 kg (male)
total body water 42L [60%/50%/70% of body weight (males/females/newborn)]
ICF, intracellular fluid 14L [67%-55% of total body water]
ECF, extracellular fluid 28L [33%-45% of total body water]
plasma 3L [4% of body weight]
interstitial volume 11L [16% of body weight]
PNa, concentration of sodium ions (Na+) in plasma 140 mmol/L
PK, concentration of potassium ions (K+) in plasma
PCl, concentration of chloride ions (Cl−) in plasma
PHCO3, concentration of bicarbonate ions (H CO3− ) in plasma
NKCC-1, Na+, K+, 2 Cl− cotransporter 1
NHE-3, sodium hydrogen cation exchanger-3
PAlbumin, concentration of albumin in plasma
PAldosterone, concentration of aldosterone in plasma
ANP, atrial natriuretic peptide
EABV, effective arterial blood volume
AQP, aquaporin water channel
GFR, glomerular filtration rate
PCT, proximal convoluted tubule
DtL, descending thin limb (of the loop of Henle)
AtL, ascending thin limb (of the loop of Henle)
mTAL, medullary thick ascending limb (of the loop of Henle)
cTAL, cortical thick ascending limb (of the loop of Henle)
DCT, distal convoluted tubule
CCD, cortical collecting duct
MCD, medullary collecting duct
CDN, cortical distal nephron, which consists of the late DCT, the connecting segment, and the CCD
NKCC-2, Na+, K+, 2 Cl− cotransporter 2
ROMK, renal outer medullary K+ channel
NCC, Na+, Cl− cotransporter
ENaC, epithelial Na+ channel
Ca-SR, calcium-sensing receptor
SPAK, STE20-related proline-alanine-rich-kinase
OSR1, oxidative stress response kinase type 1
SGK-1, serum and glucocorticoidregulated kinase-1
Ksp, solubility product constant for the activity of ions in a solution
Na+ 150 10-20
K+ 4.0 120-150
Cl− 113 ∼5
HCO3− 25 10
Phosphate 2.0 (inorganic) ∼130 (organic in macromolecules)
projekty/ehalperin.txt · Poslední úprava: 2019/08/20 20:47 autor: kofranek