Fluid, Electrolyte, Acid-Base

Fluid Balance

Amount of water gained = amount of fluid lost

Electrolyte Balance

Ion gain = ion loss

Acid-Base Balance

H+ gain is offset by loss

Major ways of gain

Drinking, consuming high-water content, and water produced during cellular respiration

Major ways of loss

Urination, sweating, breathing, defecation

Major extracellular fluids

Plasma, interstitial fluid, lymph

How are fluids and electrolytes regulated in the body?

Responses to plasma volume or osmotic concentrations

Cations inside the cell

Sodium

Potassium

Magnesium

Cations outside the cell

Sodium

Potassium

Calcium

Anions inside and outside the cell

Chloride

Proteins

Phosphates

Bicarbonate

SO4

Function of ADH

Stimulates water consumption and thirst

Function of Aldosterone

Controls NA+ absorption and K+ loss

Natriuretic Peptides

Reduce thirst and block ADH+Aldosterone

Hyponatremia

Na+ concentration in ECF is reduced

Hypernatremia

Na+ in ECF is too high

Normal pH of ECF

7.35-7.45

Acidemia

Less than 7:35 pH

Alkalemia

More than 7.45 pH

If ECF hypertonic

Water moves from ICF to ECF

If ECF hypotonic

Water moves from ECF to cells

Electrolyte imbalance

Sodium ion imbalance

Rate of sodium uptake

Directly proportional to dietary intake

Sodium losses

Urine + respiration

Low sodium (NA+)

ADH/Aldosterone

High Sodium (NA+)

ANP secreted

Buffer

Helps stabilize the pH of a solution with H+ ions

Role of Calcitriol (Active form of Vitamin D)

Absorption of calcium and phosphate

Hypertonic

Higher solute concentration than in the cell, water moves out

Hypotonic

Lower concentration than the cell, water moves in

CO2 and pH

Inverse relationship