27 terms

ap fluid & electrolytes

ap fluid & electrolytes
Extracellular fluid (ECF)
makes up the internal environment of the body
1. plasma
2. interstitial fluid = around cells of body
3. lymph
4. transcellular (ex. CFS, synovial fluid)
intracellular fluid
water inside the cells
intracellular fluid functions
solvent that functions to facilitate intracellular chemical reactions that maintain life
Extracellular fluid functions
1. provides a relatively constant environment for cells
2. transporting substances to and from cells
1. Ions in the blood
2. Include: Na+, K+, Cl- (chloride), HCO3-, Ca2+, etc
Na+ Ions
1. Dominant ECF cations
2. Responsible for 90-95% of osmotic pressure
K+ Ions
Dominant ICF cations
Important cations
Na+ = sodium
Ca++ = calcium
K+ = potassium
Mg++ = magnesium
important anions
CI- = chloride
HCO3- = bicarbonate
elevated plasma Na+
decreased Na+
- elevated K+ levels in plasma
- decreased K+ levels
Serum Electrolytes: Sodium (Na)*
Cation - primarily in ECF
Involved in fluid balance
Sodium-potassium pump
Membrane potential
Serum Electrolytes: Potassium (K).*
Cation - primarily in ICF
Membrane potential
Sodium - potassium pump (nervous conduction) is why it's not in ECF
Not involved in fluid balance
Heart very effected
Serum Electrolytes: Calcium (Ca)
Cation - primarily in ECF
Muscle contraction (stored in muscle cell)
Nerve conduction
Skeletal growth
Blood coagulation
Gland secretion
Serum Electrolytes: Magnesium (Mg)
Cation - primarily in ICF
Helps maintain normal muscle and nerve function
Heart rhythm
Immune system
Regulate blood sugar levels
Involved in energy metabolism and protein synthesis
Cofactor in a lot of enzymes
Serum Electrolytes: Bicarbonate (HCO3)
Anion - primarily in ECF
Buffer - acid-base balance
Water enter the body by:
Drink (measure by IV & drink)
Food = fruits & vegtables
Metabolism = H20 made in cellular respiration, catabolism
Water leaves the body by:
Lungs = humidify air, exhaling (regular & rapid) air
Sensible water loss
you can measure (drink, urine)
Insensible water loss
can't measure
Regulation of Water Content
1. Total volume of water in body remains constant
2. Kidneys are primary regulators of water excretion - which are directly controlled by ADH, controls water
what controls water
ADH directly controls water. kidneys regulate
Water content determined by?
osmoreceptors in hypothalamus. Totally based on osmotic pressure in blood.
Increased fluid loss results in?
Triggers thirst and ADH secretion
Decreased fluid loss results in?
Inhibits thirst and ADH secretion