I Body Water a Compartments i Total body water TBW 60 1 Intracellular body water ICW 40 2 Extracellular body water EBW 20 a Plasma intravascular fluid b c Transcellular fluid Interstitial extravascular fluid ii Body water over the years iii Composition of body water iv Plasma serum and clotting factor II Electrolyte Balance a Electrolytes i ii Clinically important Na K Ca Mg Cl bicarbonate phosphate Ionized salts dissolved in water b Regulation c Regulatory Na K pump 3Na out 2 K in i Electrolyte concentration in plasma is different than concentration in cell concentrations must be normal and balanced for body to function ii Electrolyte regulation is dynamic 1 4 processes work together to maintain normal limits 2 3 electrolyte intake absorption distribution and excretion If intake increases excretion must increase to normalize quantities If intake decreases electrolytes must be redistributes into the plasma to maintain normal plasma levels III Water and Electrolytes a Regulation i Distal out at tube and into urine ii Glucose amino acids sodium iii Will go into more detail with this later IV Body Fluids low blood volume means low BP a Sensed by baroreceptors sympathetic system vasoconstriction i Less blood to the kidney b Function i Surrounds and permeates cells ii Lubricant and solvent for metabolic chemical reactions iii Transport oxygen nutrients chemical messengers waste products iv Regulates body temperature c Fluid homeostasis dynamic process involving the interplay of 4 subprocesses fluid intake absorption distribution excretion d Regulation i ECW osmolarity and volume is regulated by 1 Hypothalamus 2 RAAS 3 Natriuretic peptides ii Hypothalamus 1 Neuron stimulation of water output area in hypothalamus 2 Stimulate ADH production in hypothalamus and release will cause thirst sensation from posterior pituitary 3 ADH induces water absorption in kidney 4 Reduce water output hypertonic urine iii RAAS this is a major important concept 1 Neurohormonal regulation to increase water volume and sodium reabsorption 2 Rening proteolytic enzyme made by kidney converts angiotensinogen to angiotensin I in liver 3 Angiotensin I converts to angiotensin II in lung iv Natriuretic peptides 1 Reciprocal effects to the RAAS 2 Atrial natriuretic peptide ANP 3 Brain natriuretic peptide BNP 4 C type natriuretic peptide CNP e Abnormalities i Abnormalities in 1 Volume 2 Concentration 3 Electrolyte composition ii Due to many different pathophysiological conditions iii Results in clinical disorders or death V Water Balance Disorders a Due to i Water intake and output imbalance ii Sodium intake and output imbalance b Results in i Dehydration ii Overhydration c Dehydration i Thirsty dry no sweat tears ii Glassy eyes can t swallow iii Decreased skin tugor iv Can be caused by Increased sweating 1 Kidney disease too much H2 retained by ADH 2 3 Hyperventilation 4 Diarrhea v Due to water deficit simple dehydration vi Hypernatremic dehydration hyperosmolar dehydration vii Normonatremic dehydration isomolar dehydration viii Hyponatremic dehydration hyposmolar dehydration d Overyhydration i Due to 1 Excess water intake water intoxication high TBW normal total body Na 2 Excess water and Na retention VI Electrolyte Balance Disorders a Sodium i Normal total body Na 55 mmol kg body weight mostly found in 1 Na excess including blood extracellular fluid ECW ii Abnormalities in body Na intracellular fluid 2 Na depletion iii Abnormalities in plasma Na 1 Hyponatremia low plasma Na 2 Hypernatremia high plasma Na a iv Pitting edema v Heart failure RAAS activated increase of sodium in the body Inside blood only b Potassium Increased potassium in acidosis i ii Decreased in alkalosis c Normal total body K 50 mmol kg body weight 98 found in ICW d Abnormalities of body K i K excess ii K depletion e Abnormalities of plasma K i Hypokalemia low plasma K ii Hyperkalemia high plasma K